Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes
BIBLIOGRAPHY
AGUSTIN, FLORESCA T. MAY 2007. Evaluating the Biofumigation Potentials
of Various Brassica Species for the Control of Ralstonia solanacearum (E.F. Smith)
Yabuuchi et al. Affecting Potatoes. Benguet State University, La Trinidad, Benguet.
Adviser: Lily Ann D. Lando, PhD
ABSTRACT
The application of brassica reduced the population of Ralstonia solanacearum in
the soil with broccoli as the most effective biofumigant. However, the use of cabbage cv.
scorpio significantly reduced the bacterial population. The use of chopped leaves and
whole leaves effected the greatest reduction in the bacterial population. Among plant
tissues, leaves effected a higher reduction in R. solanacearum population. In reducing
bacterial population, the best combinations of biofumigant and tissue preparation were
chopped leaves of broccoli, whole leaves of cauliflower, macerated roots and stems of
cabbage cv. scorpio, and macerated leaves of mustard. The bacterial population in the
untreated soil increased continuously over the sampling period.
TABLE OF CONTENTS
Page
Bibliography. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
Table of Contents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
REVIEW OF LITERATURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
MATERIALS AND METHODS
Source of Test Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Preparation of Brassica Tissues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Evaluation of Bactericidal Potential of
Brassica Tissues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Laboratory Experiment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Data Gathered . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
RESULTS AND DISCUSSION
Effect of Biofumigant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Effect of Tissue Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Interaction Effect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
SUMMARY, CONCLUSIONS AND RECOMMENDATIONS . . . . . . . . . . . 22
LITERATURE CITED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
APPENDICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
ii
INTRODUCTION
Potato (Solanum tuberosum Linn.) ranks fourth among the most valuable crops
grown worldwide. It provides of low-cost energy to the human diet and is a good source
of carbohydrates, starch, proteins minerals, vitamins A and B2 and some elements such as
potassium and phosphorus (Kipps, 1979). In the Philippines, potato ranks third in
production among the leading commercial vegetable crops and first among the vegetables
in Northern Luzon. At present, 75% of the total production in the Cordillera region is
from the province of Benguet. The suitability of potato production in Benguet (1600-
2300 meters ASL) gives its estimated yield at 15.10 MT/ha (HARRDEC, 1996 as cited
by Lando, 2002). However, this is seldom met due to losses from the occurrence of pest
and diseases.
Bacterial wilt (BW) caused by Ralstonia solanacearum (E.F. Smith) Yabucchi et
al. is the most serious soil-borne disease of solanaceous crops such as potato, tobacco,
tomato and eggplant causing losses in quality and quantity of production (ACIAR, 2000).
Perez et al. (1997) have shown that the disease has become severe in the highland and
lowland potato production areas. R. solanacearum is capable of enduring in the soil and
has a wide host range (Urquhart and Mienie, 1997 as cited by Lando, 2002). The host
range includes 55 plant families especially members of Solanaceae.
Control measures are usually done through crop rotation, strict sanitation, use of
resistant cultivars, use of disease-free planting material, and minimum tillage.
Biofumigation using brassica tissues also decreases the incidence and severity of
bacterial wilt (ACIAR, 2000). However, using different combination of control measures
is more preferred to lessen the impact of the pathogen.
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
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Biofumigation refers to the suppression of soil-borne pests and pathogens by
naturally-occurring biocidal compounds, principally isothiocyanates (ITCs), released into
the soil from decomposing organic material (ACIAR, 2000). Isothiocyanate compounds
are similar to the methyl isothiocyanate (MITC) toxin from the metham sodium soil
fumigant. These are highly biocidal to a diverse range of organisms including bacteria,
nematodes, fungi, insects, and germinating seeds (Brown and Morra, 1997; Kirkegaard et
al., 1994; Potter et al,, 1998 and Walker, 1997). Thus, biofumigation may provide an
option for farmers to manage BW based on their circumstances of disease pressure,
economics and their ideals for cropping system.
Bacterial wilt is difficult to manage because it is soil-borne and seed-borne and
there is no readily available chemical control. There is also great variation in the
bacterium often manifested in a wide host range. Severely infested soils are not planted to
potato anymore or are used in other industrial purposes. Thus, further reducing the
potential potato production.
Biofumigation potentially provide a sustainable disease control option, for
integrated BW management system while simultaneously improving soil health (soil
fertility). The incorporation of biofumigants into the soil provides valuable organic
matter, possibly reducing the dependence on organic fertilizers. Other benefits of
biofumigation include improved soil texture, increased water holding capacity and
improved microbial community structure (Harvey and Sams, 1999). The results of this
study would help seed companies to develop biofumigant-type crucifers. Finally would
open up opportunities in controlling other soil-borne pest and pathogens of other crop.
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
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This study therefore aimed to evaluate the biofumigation potential of brassica for
the control of R. solanacearum population in the soil, identify the brassica which is most
effective biofumigant and determine the best method of brassica tissue preparation for
biofumigation.
The study was conducted at the Department of Plant Pathology Laboratory and
Greenhouse, Benguet State University, La Trinidad, Benguet from June to December
2005.
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
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REVIEW OF LITERATURE
The Disease
Bacterial wilt (BW) is one of the most important, widespread and lethal bacterial
diseases of plants (Ma, 1990 as cited by Lando, 2002). It is considered a dreaded disease
in many parts of Asia, Africa, and Central and South America. In 2000, the Australia
Centre for International Agricultural Research (ACIAR) recognized it as one of the most
important diseases of bacterial origin in the world. Bacterial wilt is the number two
constraint on potato production in over 40 developing countries (CGIAR, 2005).
Hayward in 1985 reported that more than 55 crops and wild species are affected
by R. solanacearum crops such as potato, tobacco, tomato, eggplant, banana, chili, bell
pepper and peanut are highly susceptible to the disease. Recently it was shown that
certain ecotypes of the model plant Arabidopsis thaliana are also susceptible to the
pathogen (Hayward, 2000). An endemic strain (race 1, biovar 1) was detected in 2001 in
geraniums (Pelargonium sp.) in Florida, USA (Momol et al., 2003). It is common in
tropical, subtropical and warm temperature regions where temperature and moisture
conditions are favorable for its development (Singh, 1978). The bacterium may also be
present in cooler climates such as relatively high elevation in the tropics or higher
latitudes.
The Causal Organism
The bacterium responsible for bacterial wilt is Ralstonia solanacearum (E. F.
Smith) Yabucchi et al., (1996) formerly known as Pseudomonas solanacearum E. F.
Smith. It is a Gram negative, strictly aerobic, nospore-forming, noncapsulate, nitrate
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
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reducing, catalase-positive, ammonia-forming, and monotrichous short rod (1.5 x 0.5
mm) (Sands et al., 1980; Stanier et al., 1966). The wild type bacterium is usually
nonmotile and does not form a polar flagellum in a liquid medium. Avirulent variants that
develop in culture are actively motile. Colonies on agar are opalescent which became
darker with age. Rich (1983) described them as small, irregular, smooth, wet and shiny.
The virulent colonies are pink in tetrazolium chloride agar (TCZA). The optimum
temperature for growth ranges from 350C- 370C (Weber, 1973 and Rich, 1983) and the
thermal death point lies at about 520C (Kerr, 1983).
R.
solanacearum cannot hydrolyze starch and it can liquefy gelatin slowly or not
at all. The bacterium is inhibited by relatively low concentrations of salt in broth culture
and is sensitive to desiccation.
The cultured bacterium in unaerated liquid media losses its virulence and viability
rapidly and change from the fluidal (nonmotile) wild type to the avirulent, highly motile
variants.
Symptoms
Bacterial wilt is described by Agrios (1997) as sudden wilt. Infected plants die
rapidly. Older leaves may first show leaf dropping and discoloration or one-sided wilting
and stunting before completely wilts and permanently dies. Severely infected tubers are
blackened and when cut, vascular ring turns brown. In general, the symptoms are wilting,
stunting and yellowing of the leaves, followed by the collapse of the entire plants
(Agrios, 1978).
Symptoms occur both above and belowground parts of the host plants. Above
ground symptoms include wilting, stunting, and yellowing of leaves. Infection is
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
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characterized by initial wilting only of a part of the stems of the plant, or even one side of
the leaf or stem. The entire plant wilts quickly without yellowing when development of
the disease is rapid (French, 1996).
External symptoms on the tuber are visible at harvest when infection is severe.
Bacterial ooze collects at tuber eyes causing soil to adhere (CIP, 2004). Brownish
discolorations on the vascular rings are observed. When tubers are slightly squeezed,
ooze comes out naturally from the rings. In more advance stages of the disease
development, the vascular ring or the whole tuber may disintegrate completely (Bahar
and Danish, 1990; Martin and French, 1996).
Survival
Bacteria live in follow soil for 6 years or more and may persist indefinitely in the
presence of susceptible plants (Pope, 1995). R. solanacearum is capable of surviving
under high moisture. This proves the field observation that BW is more serious in wet,
humid, tropical areas than in desert areas, even under irrigation (Buddenhagen and
Kelman, 1964). However, survival depends on race involved and depends on deep soil
layer (Persley, 1995).
Management
French (1996) stated that the inherent variability of R. solanacearum and the
strong influence of environmental conditions on resistance make disease management
difficult. In managing the disease, crop rotation, prevention and use of resistant cultivars
are employed (Geesteranus as cited by Lando, 2002).
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
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Using areas free of the bacterium reduces the chance of tubers of becoming
infected later. In a field infested with BW it takes at least 2 years rotation with non-
susceptible crops to decrease its population. Planting pathogen-free seed tubers will
decrease severity and incidence in infested field and will prevent the introduction of the
pathogen into non-infected area. The elimination of alternate hosts can decrease pathogen
population inoculum in the soil. The use of resistant cultivars play an important role but
the extreme variability found in R. solanacearum makes breeding for resistance to the
pathogen difficult (Sequeria, 1983).
Biofumigation
Biofumigation has been shown to reduce the levels of several soil pathogens,
including bacterial wilt and root knot nematode. Isothiocyanates (ITCs) were released
from brassica tissues when glucosinolates (GSLs) are hydrolyzed by endogenous
myrosinase enzyme (Angus et al., 1994). These hydrolysis products (ITCs) are known to
have broad biocidal activity including insecticidal, nematicidal, fungicidal, antibiotic and
phytotoxic effects (reviewed by Brown and Morra, 1997). The difference in structure of
individual GSLs and ITCs depends on their organic side-chain (aliphatic, aromatic or
indole). Their concentrations, profiles, distribution and toxicity varies within and between
brassica species and in different plant tissues, hence, the concentration and type of
biocidal hydrolysis product involved also varies (Kirkegaard and Sarwar, 1998).
Biofumigation is one of the newest technology as a component of integrated pest
management. Potential of brassicas (ITCs) were observed during the early 1990s when
wheat crops grew vigorously following brassica break crops such as canola and Indian
mustard than other break crops such as linseed or oats (Angus et al., 1991; Kirkegaard et
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
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al., 1994). In the study of Kirkegaard et al. (1998), they grew wheat in pots inoculated
with the take-all fungus (Gaeumannomyces graminis var. tritici) and incorporated the
root residues of canola. Results showed lower take- all infection on wheat after brassicas
compared to linseed. Aromatic GSL present in canola roots have been shown to be highly
toxic to cereal fungal pathogens and genetic diversity within Australian canola varieties
allows selection of higher root GSL levels (Kirkegaard and Sarwar, 1999).
The work of Harding and Wicks (1999) shows that ITCs emanating from Brassica
juncea (Indian mustard) meal, B. juncea/B. napus (canola) leaves and roots are inhibitory
to a number of significant fungal pathogens of potato (Rhizoctonia AG3, Rhizoctonia AG8,
Verticillium dahliae (A and B), Colletotrichum coccodes (A and B), Phytophthora
erythroptica and P. coryptogea).
The preliminary studies on bacterial wilt caused by R. solanacearum indicate that
tissues of mustards (B. juncea, B. nigra and B. carimata) are more suppressive than those
of other brassicas tested suggesting that 2-propenyl GSL is the active compound (Akiew,
unpublished). This compound is also present in kale and cabbage indicating residues
from these crops may also have activity against BW. The results of the study of Akiew in
1999 demonstrate reductions of 40-80% in BW in the field by Indian mustard green
manure and up to 97% reduction in the glasshouse when combined with organic soil
amendments. A commercial Indian biofumigant (FUMUS) showed potential to reduce
levels of BW and increase potato yield dramatically (from 0.3-22 tons/ha) in an on-farm
trial in Victoria (ACIAR, 2000; Akiew et al., 1996).
In an experiment at Southedge Research Station BW nursery, Australia, the
radish, fodder rape and mustard biofumigants were all effective in delaying disease onset,
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
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reducing the incidence and severity of BW and increasing eggplant yield (ACIAR, 2000).
Incorporation of some brassica fumigants has reduced BW by 50-60-% in three of the
four experiments of ACIAR in 2002 compared to non – brassica controls.
In north Queensland, Australia, results in some of the field trials have been
excellent. A paddock with high-level infection of bacterial wilt was planted with
tomatoes. An untreated block yielded less than two tons of tomatoes, while the area
where a brassica green manure treatment had been applied yielded up to 20 tons of
tomatoes and had correspondingly lower levels of bacterial wilt (Taylor, 2006).
In the Philippines, trials have been planted at a range of field sites, from high-
elevation areas in Benguet, with cabbages, potatoes and other temperate crops, down to
lowland areas in Mindanao, where eggplants and tomatoes are the major crops.
According to Kirkegaard (2006) the most promising treatments (radish, mustard and
broccoli) have reduced bacterial wilt significantly (50 to 60%) in most of the
experiments.
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
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MATERIALS AND METHODS
Sources of Test Materials
Ralstonia solanacearum was isolated from naturally infected potatoes and pure
culture was prepared following standard procedures. Brassicas were collected from
the fields in Atok, Kabayan, La Trinidad, and Tuba, Benguet.
Preparation of Brassica Tissues
Brassica plants were collected. Soil was washed from the roots of all plants and
subsamples from each sample were separated into stem and root tissue and leaf tissue.
Macerated specimens were first cut into pieces then blended, chopped specimens were
cut into at least 2-3 cm long pieces and whole tissue specimens were used as is.
Each treatment was replicated thrice and arranged in a factorial completely
randomized design (CRD) with plant species as factor A and the different type of plant
tissue and method of preparation as factor B. The treatments were as follows:
Factor A Plant Species
A0 Untreated (Control 1)
A1 Sunflower - Control 2 (Tithonia diversifolia )
A2 Broccoli cv. Marathon (Brassica oleracea var. italica)
A3 Cauliflower cv. Milkyway (Brassica oleracea var. botrytis)
A4 Cabbage cv. Scorpio (Brassica oleracea var. capitata)
A5 Cabbage cv. Rareball (Brassica oleracea var. capitata)
A6 Radish cv. Mino early (Raphanus sativa)
A7 Mustard cv. Montana (Brassica juncea)
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
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A8 Pechay (Brassica pekenensis)
A9 Radish + Mustard (1:1)
Factor B Types of plant tissue and methods of preparation
B1 Macerated stems and roots
B2 Macerated leaves
B3 Chopped roots and stems
B4 Chopped leaves
B5 Whole roots and stems
B6 Whole leaves
Evaluation of the Bactericidal Potential of Brassica Tissues
Laboratory
Experiment. One hundred ml of bacterial suspension was incorporated
with 200 g sterile soil in plastic cups and allowed to stand for two days. A 10 - g soil
sample was then taken to determine initial population (cfu/g soil) of the bacterium and
Brassica tissues (10g/200g of soil) were incorporated. Bacterial population in the soil was
monitored weekly for five weeks following standard procedures.
Data Gathered
The following were the data gathered/computed:
1. Colony counts. Colonies that shows the typical characteristics of the
bacterium were counted.
2. cfu/g soil was calculated as follows:
average colony count x DF
amount plated
cfu/g soil= ---------------------------------------------
10 g soil
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
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a. Initial population (cfu/g soil). The initial population of the bacterium in the
soil was measured two days after inoculation.
b. Weekly population (cfu/g soil). Soil samples were obtained from the
treatments every week for five weeks.
c. Final population (cfu/g soil). Final population was taken on the fifth week
from inoculation.
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
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RESULTS AND DISCUSSIONS
Effect of Biofumigant
After seven days from incorporation, the brassica biofumigants had an immediate
effect in reducing the Ralstonia solanacearum population except for sunflower, cabbage
and pechay in which there was an increase in bacterial population (Table 1). Generally,
the bacterial population decreases with the application of biofumigants, however there
were slight increase observed during the second to the fourth assessment period. Results
revealed that the application of broccoli consistently decrease R. solanacearum
population in the soil. On the other hand, the bacterial population in the soil treated with
pechay consistently increase. On the final week, there was a decrease in R. solanacearum
population in most of the treatments. Greatest reduction in bacterial population was
observed in the soil treated with broccoli followed by cabbage cv. scorpio, radish +
mustard, cabbage cv. rareball and cauliflower (Figure 1). There was an increase in
bacterial population in the untreated soil and the soil treated with pechay and radish. This
shows that pechay had no impact in reducing R. solanacearum population. Pechay
decomposed much faster than the other biofumigants. The ease by which pechay
decomposed may have caused the release of ITC’s much faster than the other treatments,
thereby causing the faster dissipation of any biofumigant content. It was also the findings
of ACIAR that pechay had no effect on the reduction of R. solanacearum population. The
application of radish show a negative effect in the reduction of bacterial population, this
proves that GSL content varies within brassica varieties (ACIAR, 2000).
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
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Table 1. Effect of biofumigant on the population of R. solanacearum (log cfu x 104)
BIOFUMIGANT ASSESSMENT
PERIOD
Initial
Week 1
Week 2
Week 3
Week 4
Week 5
Sunflower
0.6bc 0.76a 0.84ab 0.61ab 0.54c 0.52bc
Broccoli
0.61bc 0.52b 0.43d 0.41c 0.32d 0.29e
Cauliflower
0.68b 0.57b 0.67bc 0.55ab 0.38d 0.44cd
Cabbage cv. Scorpio
0.59bc 0.66ab 0.78ab 0.62ab 0.56bc 0.32de
Cabbage cv. Rareball
0.42d 0.57b 0.94a 0.67a 0.68ab 0.43cd
Radish
0.56c 0.52b 0.69bc 0.56ab 0.77a 0.62ab
Mustard
0.94a 0.79a 0.68bc 0.62ab 0.58bc 0.65a
Pechay
0.53c 0.56b 0.59cd 0.66ab 0.67ab 0.68a
Radish + Mustard
0.68b 0.6b 0.55cd 0.54b 0.43d 0.41cd
Untreated
0.95a 0.92a 0.93a 1.06a 1.23a 1.31a
The ITCs produced vary between brassica species and toxicity may sometimes
differ among organisms (Brown and Morra, 1997). The level of glucosinolates in broccoli
is higher than in other crucifers and was highly biocidal to a diverse range of organisms
including nematodes, bacteria, fungi, insects and germinating seeds (Kirkegaard et al.,
1994 and Brown and Morra, 1997). The positive effect of sunflower show, on the other
hand, that even nonbrassicaceous organic matter may reduce R. solanacearum
population. This may point to other non GSL-related effects caused by the decomposing
organic matter.
Guilabo (2005) stated that broccoli and cauliflower decreased the population of R.
solanacearum in the soil. In addition the application of cauliflower effectively reduced
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
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bacterial wilt incidence. Furthermore, Akiew (1999) cited that the application of mustard
reduced bacterial wilt at 40-80 %. According to the ACIAR project on biofumigation the
most promising brassica tested in the Philippines (using radish, mustard and broccoli)
have reduced bacterial wilt by 50 to 60 %. The reduction in bacterial population reduces
the inoculum in the soil and will in turn reduce the incidence and severity of disease.
WEEK1
WEEK5
Untreated
0.92
1.31
0.41
Radish + Mustard
0.6
Pechay
0.56 0.68
0.65
Mustard
0.79
Radish
0.520.62
0.43
Cabbage cv. Rareball
0.57
0.32
Cabbage cv. Scorpio
0.66
0.44
Cauliflower
0.57
0.29
Broccoli
0.52
0.52
Sunflower
0.76
0
0.2
0.4
0.6
0.8
1
1.2
1.4
log cfu/g soil
Figure 1. The change in the R. solanacearum population in the soil as affected by the
biofumigants (week 1 and week 5)
Effect of Tissue Preparation
Generally, there was an increase in the population of Ralstonia solanacearum
after seven days of incorporating biofumigants. However, immediate reduction in
bacterial population was observed with the use of chopped roots and stems and whole
leaves. The general trend from week 2 to week 4 was decrease of bacterial population
although in some treatments there was a slight increase in population. On the final week,
all the treatments had reduced R. solanacearum population in the soil (Table 2). The
greatest reduction was effected by the application of chopped leaves but was not
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
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significantly different from the use of whole leaves. Between the root and stem and leaf
tissues, the leaf tissue effected the higher reduction of bacterial population (Figure 2).
The leaves decomposed faster than the roots and stems, thus production of ITCs is also
faster.
Table 2. Effect of tissue type and preparation on the population of R. solanacearum (log
cfu x 104)
TISSUE TYPE
ASSESSMENT PERIOD
AND
Initial
Week 1
Week 2
Week 3
Week 4
Week 5
PREPARATION
Macerated roots and
stems 0.54c 0.68ab 0.73a 0.63ab 0.53a 0.51ab
Macerated leaves
0.68ab 0.71a 0.76a 0.47c 0.55a 0.52ab
Chopped roots and
stems 0.75a 0.64ab 0.64ab 0.66a 0.55a 0.55a
Chopped leaves
0.58c 0.6abc 0.63ab 0.59ab 0.59a 0.38c
Whole roots and
stems 0.51c 0.56bc 0.57b 0.53bc 0.63a 0.51ab
Whole leaves
0.68ab 0.51c 0.79a 0.59ab 0.47b 0.44bc
In general, green fresh leaf residues of brassica incorporated in the soil released
greater amounts of ITCs and may suppress pests better than the dried or mature residues
as those found in roots and stems. As Matthiessen et al. (2001) noted, aromatic ITCs
produced from GSLs often found in roots are very toxic but they are of low volatility and
that contact with organisms may be reduced. Aliphatic ITCs found mostly on shoots are
less toxic but of greater volatility that allow easier contact with organisms. As shoot is
generally very much greater than root biomass, shoots contribute more of the total ITC
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
17
potential (Matthiessen and Kirkegaard, 1998). ACIAR Project No. SMCN/200/114 points
out that tissue disruption increases the efficiency of release of ITCs achieved by rough
chopping and blending/ macerating. By chopping the plant cells, the vacuoles in which
the GSLs are stored were destroyed and able to meet the myrosinase enzyme in the
cytoplasm. However, macerated plant tissues in this experiment show a lower reduction
in the bacterial population compared to chopped and whole plant tissues. This was maybe
due to faster loss of isothiocyanates. Longer-term incubation (30 days) of tissues that
were not macerated can sometimes effective as macerated amendments against BW
(ACIAR, 2000). ACIAR (2000) thus concluded, “The general longer-term impacts of
organic amendments can also play a role in pest suppression presumably due to induced
changes in the soil microbial community favoring pest antagonist”.
WEEK1
WEEK5
0.44
Whole leaves
0.51
0.51
Whole roots and stems
0.56
0.38
Chopped leaves
0.6
0.55
Chopped roots & stems
0.64
0.52
Macerated leaves
0.71
0.51
Macerated roots & stems
0.68
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
log cfu/g soil
Figure 2. The change in the R. solanacearum population in the soil as affected by the
tissue preparation (week 1 and week 5)
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
18
Interaction Effect
Figure 3 shows the decrease in the population of R. solanacearum in the selected
best combinations of biofumigants and tissue preparation. The use of chopped leaves of
broccoli, whole leaves of cauliflower, macerated roots of cabbage cv. scorpio, macerated
leaves of mustard, whole leaves and chopped leaves of radish + mustard effected the
greatest reduction. The summary of the changes in the population of R. solanacearum
was presented in Figure 5.
WEEK1
WEEK5
0.17
chopped leaves of radish + mustard
0.64
0.11
whole leaves of radish + mustard
0.61
0.19
macerated leaves of mustard
0.33
macerated roots and stems of
0.08
0.88
cabbage cv. scorpio
0.19
whole leaves of cauliflower
0.77
0.05
chopped leaves of broccoli
0.31
0
0.2
0.4
0.6
0.8
1
log cfu/g soil
Figure 3. Decrease in the population of R. solanacearum in the selected best
combinations of biofumigant and tissue preparation
The greatest increase in the bacterial population was observed in untreated soil, and in
soil treated with whole roots and stems of cabbage cv. rareball, macerated roots and
stems of sunflower, chopped roots and stems of sunflower, macerated leaves and whole
leaves of pechay (Figure 4). The GSL types and concentrations vary within and between
brassica species and in the different plant tissues (Brown and Morra, 1997). It is also
affected by age, health and nutrition and edaphic environment in which tissues are
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
19
incorporated. The nutrients supplied to the plant during its growth affects the level of
GSL. Efficiency of release of ITCs from incorporated tissues is also influence by the type
of soil, moisture content and degree of tissue disruption.
These results further indicate the potential use of biofumigation for the control of
Ralstonia solanacearum. The range in glucosinolate profiles, the differential toxicity of
isothiocynate to different pest and the wide range in phenological and morphological
diversity in brassica provides significant scope to select or breed brassicas with enhanced
biofumigation potential for a particular target organism (Kirkegaard et. al., 1998).
WEEK1
WEEK5
1.31
untreated
0.92
0.91
whole leaves of pechay
0.7
1.21
macerated leaves of pechay
0.43
whole roots and stems of cabbage
0.88
0.24
cv. rareball
chopped roots and stems of
1.09
0.93
sunflower
macerated roots and stems of
0.75
0.51
sunflower
0
0.2 0.4 0.6 0.8
1
1.2 1.4
log cfu/g soil
Figure 4. The greatest increase in the population of R. solanacearum as affected by the
combinations of biofumigant and tissue preparation
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
20
SUNFLOWER
WEEK1
WEEK5
1.31
Untreated
0.92
0.2
Whole leaves
0.63
0.16
Whole roots and stems
0.41
0.28
Chopped leaves
0.81
1.09
Chopped roots & stems
0.93
0.66
Macerated leaves
1.24
0.75
Macerated roots & stems
0.51
0
0.2
0.4
0.6
0.8
1
1.2
1.4
log cfu/g soil
BROCCOLI
WEEK1
WEEK5 CAULIFLOWER
WEEK1
WEEK5
0.92
1.31
0.92
1.31
0.34
0.39
0.19
0.77
0.45
0.82
0.7
0.68
0.05
0.33
0.31
0.46
0.2
0.51
0.48
0.34
0.33
0.36
0.85
0.61
0.55
0.3
0.34
0.55
0
0.5
1
1.5
0
0.5
1
1.5
log cfu/g soil
log cfu/g soil
CABBAGE cv. SCORPIO
WEEK5
CABBAGE cv. RAREBALL
WEEK5
WEEK1
WEEK1
0.92
1.31
0.92
1.31
0.24
0.52
0.
0.19 29
0.07
0.88
0.27
0.24
0.1
0.26
0.63
0.26
0.3
0.47
0.9
0.49
0.86
0.36
1.03
1.03
0.08
0.42
0.88
1.12
0
0.5
1
1.5
0
0.5
1
1.5
log cfu/g soil
log cfu/g soil
Figure 5a. Summary of the changes in the population of R. solanacearum as affected by
the biofumigant and tissue preparation
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
21
RADISH
WEEK1
WEEK5
MUSTARD
WEEK1
WEEK5
1.31
0.92
1.31
0.92
0.520.65
0.52
0.82
0.450.57
0.4
1.01
1.04
0.98
0.75 0.95
0.44
0.83
0.85
0.82
0.41
0.36
0.33
0.19
0.230.33
0.72
1.29
0
0.5
1
1.5
0
0.5
1
1.5
log cfu/g soil
log cfu/g soil
PECHAY
WEEK1
WEEK5
RADISH + MUSTARD
WEEK5
WEEK1
0.92
1.31
0.92
1.31
0.7
0.91
0.11
0.61
0.520.65
0.61
0.68
0. 0.48
35
0.17
0.64
0. 0.27
17
0.54
1.05
0.37
0.43
1.21
0.41
0.
0.62
0.
81 95
0.29
0
0.5
1
1.5
0
0.5
1
1.5
log cfu/g soil
log cfu/g soil
Figure. 5b. Summary of the changes in the population of R. solanacearum as affected by
the biofumigant and tissue preparation
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
22
SUMMARY, CONCLUSIONS AND RECOMMENDATIONS
Summary
The study was conducted at the laboratory and greenhouse of the Department of
Plant Pathology, Benguet State University, La Trinidad, Benguet to evaluate the
biofumigation potentials of various brassica species for the control of Ralstonia
solanacearum (E. F. Smith) Yabuuchi et al. affecting potatoes.
Results showed that the application of brassica can effectively reduce the
population of Ralstonia solanacearum in the soil with broccoli as the most effective
biofumigant. However, the use of cabbage cv. scorpio significantly reduces the bacterial
population. The use of chopped leaves and whole leaves effected the greatest reduction in
the bacterial population. Among plant tissues, leaves effected a higher reduction in R.
solanacearum population. In reducing bacterial population, the best combinations of
biofumigant and tissue preparation were chopped leaves of broccoli, whole leaves of
cauliflower, macerated roots and stems of cabbage cv. scorpio, and macerated leaves of
mustard. The bacterial population in the untreated soil continuously increased throughout
the sampling period.
Conclusions
Based on the findings of this study, biofumigants can be used to reduce the soil
population of Ralstonia solanacearum. Furthermore, the incorporation of brassicaceous
“waste” material is an economical and environmentally-safe practice that can be used by
resource-poor farmers. Finally, the use of cruciferous biofumigants can be a viable
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
23
option in an integrated and long-term management of bacterial wilt disease both in
conventional and in organic production systems.
Recommendations
The following are hereby recommended:
1. A follow-up study to confirm these results must be conducted.
2. A farm trial must be conducted to evaluate the efficacy of using biofumigants
for the control of R. solanacearum in the field.
3. A study should be conducted to determine the effect of biofumigants to other
soilborne pathogens.
4. Finally, inclusion of biofumigants in integrated bacterial wilt management
should be considered.
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
24
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solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
27
APPENDICES
Appendix Table 1. Initial population of Ralstonia solanacearum in the soil (log cfu/g soil
x 104)
REPLICATION
TREATMENT I
II
III TOTAL MEAN
Sunflower
Macerated root + stem
0.52 0.32 0.4 1.24
0.41
Macerated leaf
0.34 0.49 0.68 1.51
0.50
Chopped root + stem
0.81 0.86 0.91 2.58
0.86
Chopped leaf
0.67 0.58 0.74 1.99
0.66
Whole root + stem
0.56 0.43 0.32 1.31
0.44
Whole leaf
0.4 0.94 0.81 2.15
0.72
Broccoli
Macerated root + stem
0.36 0.11 0.2 0.67
0.22
Macerated leaf
0.66 0.59 0.64 1.89
0.63
Chopped root + stem
0.92 0.85 1.14 2.91
0.97
Chopped leaf
0.77 0.2 0.23 1.2
0.40
Whole root + stem
0.7 0.41 0.67 1.78
0.59
Whole leaf
0.6 0.95 1.01 2.56
0.85
Cauliflower
Macerated root + stem
0.4 0.68 0.45 1.53
0.51
Macerated leaf
1.15 1.06 0.61 2.82
0.94
Chopped root + stem
0.88 0.87 0.72 2.47
0.82
Chopped leaf
0.3 0.32 0.53 1.15
0.38
Whole root + stem
0.18 0.32 0.4 0.9
0.30
Whole leaf
1.03 1.1 1.09 3.22
1.07
Cabbage cv. Scorpio
Macerated root + stem
0.67 0.36 0.4 1.43
0.48
Macerated leaf
0.8 0.49 1 2.29
0.76
Chopped root + stem
0.8 0.68 0.91 2.39
0.80
Chopped leaf
0.79 0.57 0.46 1.82
0.61
Whole root + stem
0.32 0.28 0.43 1.03
0.34
Whole leaf
0.64 0.45 0.51 1.6
0.53
Cabbage cv. Rareball
Macerated root + stem
0.48 0.38 0.76 1.62
0.54
Macerated leaf
0.51 0.95 0.87 2.33
0.78
Chopped root + stem
0.38 0.48 0.52 1.38
0.46
Chopped leaf
0.08 0.38 0.26 0.72
0.24
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
28
Appendix Table 1. Continued...
REPLICATION
TREATMENT I
II
III TOTAL MEAN
Whole root + stem
0.36 0.2 0.28 0.84
0.28
Whole leaf
0.11 0.2 0.32 0.63
0.21
Radish
Macerated root + stem
0.43 0.32 0.38 1.13 0.38
Macerated leaf
0.45 0.54 0.45 1.44 0.48
Chopped root + stem
0.41 0.58 0.62 1.61 0.54
Chopped leaf
0.93 1.13 1.08 3.14 1.05
Whole root + stem
0.32 0.57 0.52 1.41 0.47
Whole leaf
0.51 0.34 0.43 1.28 0.43
Mustard
Macerated root + stem
1.45 1.06 1.23 3.74 1.25
Macerated leaf
0.91 0.79 0.9 2.6
0.87
Chopped root + stem
0.95 1.06 1.09 3.1
1.03
Chopped leaf
0.81 0.43 0.54 1.78 0.59
Whole root + stem
1.07 1 0.99
3.06 1.02
Whole leaf
0.91 0.97 0.68 2.56 0.85
Pechay
Macerated root + stem
0.68 0.57 0.58 1.83 0.61
Macerated leaf
0.49 0.41 0.48 1.38 0.46
Chopped root + stem
0.4 0.26 0.36 1.02 0.34
Chopped leaf
0.45 0.48 0.49 1.42 0.47
Whole root + stem
0.69 0.56 0.34 1.59 0.53
Whole leaf
1 0.82
0.48 2.3 0.77
Radish + mustard
Macerated root + stem
0.67 0.32 0.32 1.31 0.44
Macerated leaf
0.62 0.63 0.53 1.78 0.59
Chopped root + stem
1.08 0.84 0.99 2.91 0.97
Chopped leaf
0.95 0.51 0.88 2.34 0.78
Whole root + stem
0.73 0.49 0.68 1.9
0.63
Whole leaf
0.71 0.6 0.63 1.94 0.65
Untreated
0.9
1.01 0.94 2.85 0.95
TOTAL
34.81 31.78 33.94 100.53
MEAN
0.65 0.59 0.63
0.62
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
29
ANOVA TABLE
SOURCE OF DF SS MS FC Tab F
VARIATION 0.05 0.01
Factor A
8
2.90
0.36
16.92**
2.03
2.69
Factor B
5
1.21
0.24
11.33**
2.3
3.2
A x B
40
5.65
0.14
6.59**
1.51
1.79
Error 108
2.32
0.02
TOTAL 161 12.08
CV = 29.35%
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
30
Appendix Table 2. Week one population of Ralstonia solanacearum in the soil (log cfu/g
soil x 104)
REPLICATION
TREATMENT I
II
III TOTAL MEAN
Sunflower
Macerated root + stem
0.46 0.48 0.58 1.52
0.51
Macerated leaf
0.96 1.51 1.26 3.73
1.24
Chopped root + stem
0.76 1.01 1.03 2.8
0.93
Chopped leaf
0.6 0.81 1.03 2.44
0.81
Whole root + stem
0.3 0.61 0.32 1.23
0.41
Whole leaf
0.18 0.93 0.78 1.89
0.63
Broccoli
Macerated root + stem
0.15 0.3 0.45 0.9
0.30
Macerated leaf
0.72 0.79 1.05 2.56
0.85
Chopped root + stem
0.36 0.4 0.67 1.43
0.48
Chopped leaf
0.3 0.26 0.36 0.92
0.31
Whole root + stem
0.45 1.03 0.98 2.46
0.82
Whole leaf
0.26 0.28 0.49 1.03
0.34
Cauliflower
Macerated root + stem
0.46 0.58 0.6 1.64
0.55
Macerated leaf
0.59 0.72 0.51 1.82
0.61
Chopped root + stem
0.32 0.28 0.43 1.03
0.34
Chopped leaf
0.34 0.46 0.57 1.37
0.46
Whole root + stem
0.58 0.62 0.91 2.11
0.70
Whole leaf
0.79 0.92 0.59 2.3
0.77
Cabbage cv. Scorpio
Macerated root + stem
1.32 0.34 0.97 2.63
0.88
Macerated leaf
1.43 0.88 0.79 3.1
1.03
Chopped root + stem
0.92 0.76 1.01 2.69
0.90
Chopped leaf
0.88 0.58 0.43 1.89
0.63
Whole root + stem
0.11 0.4 0.3 0.81
0.27
Whole leaf
0.08 0.26 0.38 0.72
0.24
Cabbage cv. Rareball
Macerated root + stem
0.84 1.25 1.27 3.36
1.12
Macerated leaf
1.38 1.19 0.51 3.08
1.03
Chopped root + stem
0.32 0.51 0.65 1.48
0.49
Chopped leaf
0.28 0.28 0.23 0.79
0.26
Whole root + stem
0.11 0.2 0.4 0.71
0.24
Whole leaf
0.18 0.45 0.23 0.86
0.29
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
31
Appendix Table 2. Continued...
REPLICATION
TREATMENT I
II
III TOTAL MEAN
Radish
Macerated root + stem
0.23 0.15 0.3 0.68 0.23
Macerated leaf
0.26 0.58 0.4 1.24 0.41
Chopped root + stem
0.45 0.54 0.34 1.33 0.44
Chopped leaf
0.99 1.05 1.09 3.13 1.04
Whole root + stem
0.49 0.41 0.46 1.36 0.45
Whole leaf
0.52 0.61 0.43 1.56 0.52
Mustard
Macerated root + stem
1.29 1.32 1.27 3.88 1.29
Macerated leaf
0.3 0.41 0.28 0.99 0.33
Chopped root + stem
0.6 0.95 1.01 2.56 0.85
Chopped leaf
0.63 1.03 0.59 2.25 0.75
Whole root + stem
1.37 0.78 0.88 3.03 1.01
Whole leaf
0.43 0.45 0.68 1.56 0.52
Pechay
Macerated root + stem
0.9 1.03 0.92 2.85 0.95
Macerated leaf
0.3 0.59 0.41 1.3 0.43
Chopped root + stem
0.36 0.26 0.18 0.8
0.27
Chopped leaf
0.45 0.46 0.52 1.43 0.48
Whole root + stem
0.7 0.32 0.53 1.55 0.52
Whole leaf
0.86 0.72 0.52 2.1
0.70
Radish + mustard
Macerated root + stem
0.15 0.32 0.41 0.88 0.29
Macerated leaf
0.38 0.49 0.36 1.23 0.41
Chopped root + stem
0.86 1 1.28
3.14 1.05
Chopped leaf
0.08 0.34 1.49 1.91 0.64
Whole root + stem
0.59 0.64 0.59 1.82 0.61
Whole leaf
0.69 0.53 0.62 1.84 0.61
Untreated
0.88 1.24 0.63 2.75 0.92
TOTAL
27.56 30.75 30.59 88.9
MEAN
0.51 0.57 0.57
0.55
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
32
ANOVA TABLE
SOURCE OF DF SS MS FC Tab F
VARIATION 0.05 0.01
Factor
A 8 1.44 0.18
3.92** 2.03 2.69
Factor B
5
0.72
0.14
3.14*
2.3
3.2
A x B
40
10.92
0.27
5.94**
1.51
1.79
Error 108
4.96 0.05
TOTAL 161 18.05
CV = 34.82%
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
33
Appendix Table 3. Week two population of Ralstonia solanacearum in the soil (log cfu/g
soil x 104)
REPLICATION
TREATMENT I
II
III TOTAL MEAN
Sunflower
Macerated root + stem
1.27 1.18 1.1 3.55
1.18
Macerated leaf
0.71 0.76 0.67 2.14
0.71
Chopped root + stem
0.82 1.08 0.86 2.76
0.92
Chopped leaf
0.86 1.09 0.64 2.59
0.86
Whole root + stem
0.41 0.38 0.89 1.68
0.56
Whole leaf
0.11 0.2 0.2 0.51
0.17
Broccoli
Macerated root + stem
0.32 0.15 0.36 0.83
0.28
Macerated leaf
0.74 0.36 0.3 1.4
0.47
Chopped root + stem
0.23 1.08 0.3 1.61
0.54
Chopped leaf
0.4 0.11 0.26 0.77
0.26
Whole root + stem
0.4 0.36 1.17 1.93
0.64
Whole leaf
0.41 0.3 0.56 1.27
0.42
Cauliflower
Macerated root + stem
0.15 0.28 0.59 1.02
0.34
Macerated leaf
0.53 0.7 0.93 2.16
0.72
Chopped root + stem
0.15 0.11 0.3 0.56
0.19
Chopped leaf
0.28 0.56 0.61 1.45
0.48
Whole root + stem
1.15 1.29 1.21 3.65
1.22
Whole leaf
1.21 1.15 0.92 3.28
1.09
Cabbage cv. Scorpio
Macerated root + stem
0.64 1.06 0.99 2.69
0.90
Macerated leaf
1.25 1.09 1.29 3.63
1.21
Chopped root + stem
0.89 0.36 0.52 1.77
0.59
Chopped leaf
0.91 0.4 0.26 1.57
0.52
Whole root + stem
0.08 0.41 0.3 0.79
0.26
Whole leaf
1.19 1.14 1.29 3.62
1.21
Cabbage cv. Rareball
Macerated root + stem
1.24 1.28 1.23 3.75
1.25
Macerated leaf
0.64 0.97 0.56 2.17
0.72
Chopped root + stem
0.71 1.13 1.08 2.92
0.97
Chopped leaf
0.86 0.9 1.18 2.94
0.98
Whole root + stem
0.52 0.53 0.34 1.39
0.46
Whole leaf
1.3 1.45 0.96 3.71
1.24
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
34
Appendix Table 3. Continued...
REPLICATION
TREATMENT I
II
III TOTAL MEAN
Radish
Macerated root + stem
0.81 0.76 0.72 2.29 0.76
Macerated leaf
0.83 0.6 0.6 2.03 0.68
Chopped root + stem
0.84 0.89 0.91 2.64 0.88
Chopped leaf
1.04 1.3 1.09 3.43 1.14
Whole root + stem
0.34 0.2 0.32 0.86 0.29
Whole leaf
0.56 0.38 0.3 1.24 0.41
Mustard
Macerated root + stem
0.72 0.69 0.51 1.92 0.64
Macerated leaf
1.04 1.08 0.79 2.91 0.97
Chopped root + stem
0.74 1.23 1.1 3.07 1.02
Chopped leaf
0.28 0.18 0.67 1.13 0.38
Whole root + stem
0.82 0.9 0.34 2.06 0.69
Whole leaf
0.79 0.26 0.15 1.2
0.40
Pechay
Macerated root + stem
0.74 0.8 0.9 2.44 0.81
Macerated leaf
1.24 1.06 1.3 3.6
1.20
Chopped root + stem
0.08 0.91 0.04 1.03 0.34
Chopped leaf
0.36 0.26 0.28 0.9
0.30
Whole root + stem
0.15 0.3 0.38 0.83 0.28
Whole leaf
0.87 0.51 0.36 1.74 0.58
Radish + mustard
Macerated root + stem
0.23 0.56 0.4 1.19 0.40
Macerated leaf
0.15 0.04 0.2 0.39 0.13
Chopped root + stem
0.41 0.26 0.26 0.93 0.31
Chopped leaf
1.25 0.4 0.61 2.26 0.75
Whole root + stem
0.54 0.63 1.13 2.3
0.77
Whole leaf
1.21 0.97 0.66 2.84 0.95
Untreated
0.89 1.21 0.7 2.8
0.93
TOTAL
36.42 37.03 35.89 109.34
MEAN
0.67 0.69 0.66
0.67
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
35
ANOVA TABLE
SOURCE OF DF SS MS FC Tab F
VARIATION 0.05 0.01
Factor A
8
3.37
0.42
6.15**
2.03
2.69
Factor B
5
0.93
0.19
2.72*
2.3
3.2
A x B
40
12.37
0.31
4.52**
1.51
1.79
Error 108
7.39 0.07
TOTAL 161 24.05
CV = 38.18%
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
36
Appendix Table 4. Week three population of Ralstonia solanacearum in the soil (log
cfu/g soil x 104)
REPLICATION
TREATMENT I
II
III TOTAL MEAN
Sunflower
Macerated root + stem
0.38 0.4 0.38 1.16
0.39
Macerated leaf
0.53 0.75 0.43 1.71
0.57
Chopped root + stem
1.29 1.34 1.29 3.92
1.31
Chopped leaf
0.84 0.75 0.43 2.02
0.67
Whole root + stem
0.08 0.04 0.28 0.4
0.13
Whole leaf
0.58 1.04 0.08 1.7
0.57
Broccoli
Macerated root + stem
0.61 0.86 0.7 2.17
0.72
Macerated leaf
0.41 0.45 0.41 1.27
0.42
Chopped root + stem
0.4 0.95 0.58 1.93
0.64
Chopped leaf
0.08 0.23 0.3 0.61
0.20
Whole root + stem
0.34 0.08 0.43 0.85
0.28
Whole leaf
0.34 0.15 0.08 0.57
0.19
Cauliflower
Macerated root + stem
0.18 0.36 0.43 0.97
0.32
Macerated leaf
0.85 0.64 0.15 1.64
0.55
Chopped root + stem
0.26 0.6 1.05 1.91
0.64
Chopped leaf
0.94 0.94 0.59 2.47
0.82
Whole root + stem
0.71 0.92 0.75 2.38
0.79
Whole leaf
0.15 0.2 0.2 0.55
0.18
Cabbage cv. Scorpio
Macerated root + stem
0.63 0.82 0.57 2.02
0.67
Macerated leaf
0.61 0.74 0.34 1.69
0.56
Chopped root + stem
0.4 0.64 0.43 1.47
0.49
Chopped leaf
0.97 1.31 0.95 3.23
1.08
Whole root + stem
0.08 0.15 0.15 0.38
0.13
Whole leaf
0.69 0.83 0.81 2.33
0.78
Cabbage cv. Rareball
Macerated root + stem
0.87 0.85 0.95 2.67
0.89
Macerated leaf
0.3 0.23 0.53 1.06
0.35
Chopped root + stem
0.41 0.4 0.6 1.41
0.47
Chopped leaf
0.41 0.6 0.4 1.41
0.47
Whole root + stem
0.98 0.81 0.85 2.64
0.88
Whole leaf
0.99 0.91 0.96 2.86
0.95
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
37
Appendix Table 4. Continued...
REPLICATION
TREATMENT I
II
III TOTAL MEAN
Radish
Macerated root + stem
0.95 0.92 0.98 2.85
0.95
Macerated leaf
0.11 0.26 0.23 0.6
0.20
Chopped root + stem
0.61 0.74 0.56 1.91
0.64
Chopped leaf
0.57 0.57 0.41 1.55
0.52
Whole root + stem
0.71 0.78 0.73 2.22
0.74
Whole leaf
0.36 0.32 0.32 1
0.33
Mustard
Macerated root + stem
0.73 0.72 0.78 2.23
0.74
Macerated leaf
0.18 0.2 0.15 0.53 0.18
Chopped root + stem
0.77 0.85 0.88 2.5
0.83
Chopped leaf
0.23 0.15 0.87 1.25
0.42
Whole root + stem
0.28 0.64 0.72 1.64
0.55
Whole leaf
0.87 1.03 1.07 2.97
0.99
Pechay
Macerated root + stem
0.58 0.81 0.8 2.19 0.73
Macerated leaf
0.43 0.56 1 1.99
0.66
Chopped root + stem
0.72 0.52 0.67 1.91
0.64
Chopped leaf
0.58 0.59 0.51 1.68
0.56
Whole root + stem
0.66 0.73 0.57 1.96
0.65
Whole leaf
0.78 0.67 0.62 2.07
0.69
Radish + mustard
Macerated root + stem
0.26 0.28 0.2 0.74 0.25
Macerated leaf
0.58 0.69 1.07 2.34
0.78
Chopped root + stem
0.45 0.2 0.26 0.91 0.30
Chopped leaf
0.71 0.68 0.4 1.79 0.60
Whole root + stem
0.68 0.8 0.4 1.88 0.63
Whole leaf
0.58 0.7 0.72 2
0.67
Untreated
1.26 1.2 0.72 3.18 1.06
TOTAL
29.69 33.4 31.02 94.11
MEAN
0.55 0.62 0.57
0.58
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
38
ANOVA TABLE
SOURCE OF DF SS MS FC Tab F
VARIATION 0.05 0.01
Factor A
8
0.88
0.11
3.78**
2.03
2.69
Factor B
5
0.62
0.12
4.28**
2.3
3.2
A x B
40
9.19
0.23
7.91**
1.51
1.79
Error 108
3.14
0.03
TOTAL
161
13.83
CV = 29.35%
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
39
Appendix Table 5. Week four population of Ralstonia solanacearum in the soil (log cfu/g
soil x 104)
REPLICATION
TREATMENT I
II
III TOTAL MEAN
Sunflower
Macerated root + stem
0.48 0.73 0.81 2.02
0.67
Macerated leaf
0.4 0.28 0.58 1.26
0.42
Chopped root + stem
0.41 0.6 0.78 1.79
0.60
Chopped leaf
1.05 0.91 0.63 2.59
0.86
Whole root + stem
0.28 0.36 0.04 0.68
0.23
Whole leaf
0.8 0.36 0.26 1.42
0.47
Broccoli
Macerated root + stem
0.26 0.34 0.3 0.9
0.30
Macerated leaf
0.26 0.2 0.2 0.66
0.22
Chopped root + stem
0.43 0.34 0.2 0.97
0.32
Chopped leaf
0.28 0.23 0.18 0.69
0.23
Whole root + stem
0.32 0.23 0.72 1.27
0.42
Whole leaf
0.45 0.54 0.32 1.31
0.44
Cauliflower
Macerated root + stem
0.61 0.53 0.56 1.7
0.57
Macerated leaf
0.18 0.18 0.28 0.64
0.21
Chopped root + stem
0.36 0.49 0.79 1.64
0.55
Chopped leaf
0.48 0.08 0.11 0.67
0.22
Whole root + stem
0.38 0.43 0.48 1.29
0.43
Whole leaf
0.32 0.34 0.23 0.89
0.30
Cabbage cv. Scorpio
Macerated root + stem
0.61 0.57 0.38 1.56
0.52
Macerated leaf
0.96 1.13 0.94 3.03
1.01
Chopped root + stem
0.9 0.78 0.53 2.21
0.74
Chopped leaf
0.08 0.08 0.26 0.42
0.14
Whole root + stem
0.2 0.82 0.65 1.67
0.56
Whole leaf
0.51 0.46 0.23 1.2
0.40
Cabbage cv. Rareball
Macerated root + stem
0.58 0.71 0.63 1.92
0.64
Macerated leaf
0.41 0.23 0.38 1.02
0.34
Chopped root + stem
1.07 1.2 0.82 3.09
1.03
Chopped leaf
1 0.69 1.09 2.78
0.93
Whole root + stem
1.06 0.93 0.95 2.94
0.98
Whole leaf
0.04 0.18 0.2 0.42
0.14
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
40
Appendix Table 5. Continued...
REPLICATION
TREATMENT I
II
III TOTAL MEAN
Radish
Macerated root + stem
0.28 0.6 0.54 1.42 0.47
Macerated leaf
0.86 0.96 1.18 3
1.00
Chopped root + stem
0.7 0.76 0.6 2.06 0.69
Chopped leaf
0.87 1.09 1.08 3.04
1.01
Whole root + stem
0.98 0.73 0.87 2.58
0.86
Whole leaf
0.6 0.71 0.36 1.67
0.56
Mustard
Macerated root + stem
0.49 0.52 0.61 1.62
0.54
Macerated leaf
0.23 0.18 0.3 0.71 0.24
Chopped root + stem
0.41 0.34 0.76 1.51
0.50
Chopped leaf
1.02 0.89 0.97 2.88
0.96
Whole root + stem
0.97 0.84 1.06 2.87
0.96
Whole leaf
0.41 0.4 0 0.81 0.27
Pechay
Macerated root + stem
0.43 0.94 0.85 2.22
0.74
Macerated leaf
0.7 0.96 0.86 2.52
0.84
Chopped root + stem
0.64 0.28 0.18 1.1
0.37
Chopped leaf
0.63 0.53 0.45 1.61
0.54
Whole root + stem
0.79 0.54 0.71 2.04
0.68
Whole leaf
0.72 0.99 0.79 2.5
0.83
Radish + mustard
Macerated root + stem
0.32 0.36 0.18 0.86
0.29
Macerated leaf
0.61 0.51 0.89 2.01
0.67
Chopped root + stem
0.04 0.08 0.48 0.6
0.20
Chopped leaf
0.49 0.32 0.45 1.26
0.42
Whole root + stem
0.11 0.73 0.69 1.53
0.51
Whole leaf
0.57 0.51 0.46 1.54
0.51
Untreated
1.3 1.29 1.11 3.7
1.23
TOTAL
29.04 29.72 29.85 88.61
MEAN
0.54 0.55 0.55
0.55
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
41
ANOVA TABLE
SOURCE OF DF SS MS FC Tab F
VARIATION 0.05 0.01
Factor A
8
3.08
0.38
14.41**
2.03
2.69
Factor B
5
0.56
0.11
4.21**
2.3
3.2
A x B
40
7.27
0.18
6.81**
1.51
1.79
Error 108
2.89
0.03
TOTAL 161 13.83
CV = 29.88%
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
42
Appendix Table 6. Final population of Ralstonia solanacearum in the soil (log cfu/g soil
x 104)
REPLICATION
TREATMENT I
II
III TOTAL MEAN
Sunflower
Macerated root + stem
1.07 0.34 0.83 2.24
0.75
Macerated leaf
0.71 0.62 0.65 1.98
0.66
Chopped root + stem
1.09 1.08 1.1 3.27
1.09
Chopped leaf
0.26 0.23 0.34 0.83
0.28
Whole root + stem
0.08 0.23 0.18 0.49
0.16
Whole leaf
0.2 0.23 0.18 0.61
0.20
Broccoli
Macerated root + stem
0.41 0.28 0.34 1.03
0.34
Macerated leaf
0.3 0.34 0.34 0.98
0.33
Chopped root + stem
0.41 0.2 0 0.61
0.20
Chopped leaf
0.15 0 0 0.15
0.05
Whole root + stem
0.43 0.51 0.41 1.35
0.45
Whole leaf
0.57 0.2 0.41 1.18
0.39
Cauliflower
Macerated root + stem
0.66 0.51 0.49 1.66
0.55
Macerated leaf
0.32 0.41 0.34 1.07
0.36
Chopped root + stem
0.32 0.58 0.62 1.52
0.51
Chopped leaf
0.3 0.34 0.36 1
0.33
Whole root + stem
0.61 0.74 0.7 2.05
0.68
Whole leaf
0.18 0.08 0.3 0.56
0.19
Cabbage cv. Scorpio
Macerated root + stem
0.04 0.08 0.11 0.23
0.08
Macerated leaf
0.87 0.96 0.76 2.59
0.86
Chopped root + stem
0.23 0.3 0.36 0.89
0.30
Chopped leaf
0.3 0 0 0.3
0.10
Whole root + stem
0.08 0.08 0.04 0.2
0.07
Whole leaf
0.11 0.45 1.01 1.57
0.52
Cabbage cv. Rareball
Macerated root + stem
0.43 0.52 0.3 1.25
0.42
Macerated leaf
0.41 0.28 0.4 1.09
0.36
Chopped root + stem
0.96 0.46 0
1.42
0.47
Chopped leaf
0.28 0.26 0.23 0.77
0.26
Whole root + stem
0.83 1 0.81 2.64
0.88
Whole leaf
0.04 0.3 0.23 0.57
0.19
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
43
Appendix Table 6. Continued...
REPLICATION
TREATMENT I
II
III TOTAL MEAN
Radish
Macerated root + stem
0.74 0.26 0
1
0.33
Macerated leaf
0.36 0.45 0.26 1.07 0.36
Chopped root + stem
0.66 0.89 0.95 2.5
0.83
Chopped leaf
0.91 0.99 1.03 2.93 0.98
Whole root + stem
0.78 0.51 0.43 1.72 0.57
Whole leaf
0.85 0.49 0.61 1.95 0.65
Mustard
Macerated root + stem
0.79 0.71 0.66 2.16 0.72
Macerated leaf
0.08 0.26 0.23 0.57 0.19
Chopped root + stem
0.87 0.87 0.73 2.47 0.82
Chopped leaf
1.03 1 0.81
2.84 0.95
Whole root + stem
0.36 0.41 0.43 1.2
0.40
Whole leaf
0.71 0.61 1.15 2.47 0.82
Pechay
Macerated root + stem
0.99 0.95 0.49 2.43 0.81
Macerated leaf
1.15 1.37 1.1 3.62 1.21
Chopped root + stem
0.18 0.18 0.15 0.51 0.17
Chopped leaf
0.4 0.36 0.28 1.04 0.35
Whole root + stem
0.3 0.92 0.72 1.94 0.65
Whole leaf
0.83 0.91 0.98 2.72 0.91
Radish + mustard
Macerated root + stem
0.73 0.46 0.66 1.85 0.62
Macerated leaf
0.32 0.38 0.4 1.1
0.37
Chopped root + stem
0.58 0.51 0.53 1.62 0.54
Chopped leaf
0.2 0.08 0.23 0.51 0.17
Whole root + stem
0.7 0.8 0.54 2.04 0.68
Whole leaf
0.08 0.04 0.2 0.32 0.11
Untreated
1.43 1.3 1.21 3.94 1.31
TOTAL
27.25 26.02 25.41 78.68
MEAN
0.50 0.51 0.47
0.49
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
44
ANOVA TABLE
SOURCE OF DF SS MS FC Tab F
VARIATION 0.05 0.01
Factor A
8
2.86
0.36
13.31**
2.03
2.69
Factor B
5
0.50
0.10
3.73**
2.3
3.2
A x B
40
10.02
0.25
9.32**
1.51
1.79
Error 108
2.90
0.03
TOTAL 161 16.29
CV = 33.75%
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
45
Appendix Table 7. Changes in the population of Ralstonia solanacearum as affected by the combinations of biofumigant and tissue
preparation (log cfu/g soil x 104).
TREATMENT ASSESSMENT
PERIOD
Initial Week1 Week2
Week3
Week4 Week5
Sunflower
Macerated root 0.41lmnopq 0.51klmno 1.81abcd 0.38ijklmnopqrs 0.67cdefghi
0.75cdefghij
and stem
Macerated leaf
0.50hijklmnop 1.24a 0.71bcdefghijklm 0.57efghijklmno 0.42hijklmnop 0.66cdefghijklm
Chopped root and
0.86bcde 0.93cdef 0.92abcdefghij 1.31a 0.59efghijkl 1.09ab
stem
Chopped leaf
0.66efghijkl 0.81fgh 0.86abcdefghijkl 0.67cdefghijk 0.8abcde 0.27pqrstuvw
Whole root and
0.44klmnop
0.41opqrs 0.56ghijklmnop
0.13rs 0.22nopq 0.16stuvw
stem
Whole leaf
0.72defghijk 0.63ijk 0.77abcdefghijklmn 0.57efghijklmno 0.47hijklmnop 0.20qrstuvw
Broccoli
Macerated root
0.22pq 0.3st 0.27nop 0.72cdefghi 0.30lmnopq 0.34mnopqrstuvw
and stem
Macerated leaf
0.63efghijklm 0.65efg 0.47hijklmnop 0.42hijklmnopqrs 0.22opq 0.32nopqrstuvw
Chopped root and
0.97bcd 0.48mnop 0.53ghjiklmnop 0.64defghijklm 0.32klmnopq 0.20qrstuvw
stem
Chopped leaf
0.40lmnopq 0.31rst 0.25nop 0.20pqrs 0.23nopq 0.5w
Whole root and
0.59efghijklm 0.82fgh 0.64efghijklmnop 0.28nopqrs 0.42hijklmnopq 0.45jklmnopqrs
stem
Whole leaf
0.85bcde 0.34pqrst 0.42ijklmnop 0.19pqrs 0.43hijklmnopq 0.39lmnopqrstuv
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
46
Appendix Table 7. Continued...
Cauliflower
Macerated root 0.51ghijklmnop 0.55klmn 0.34lmnop 0.32lmnopqrs 0.56efghijklm 0.55ghijklmnop
and stem
Macerated leaf
1.01abc 0.61jklm 0.72bcdefghijklm 0.55efghijklmn 0.21opq 0.35lmnopqrtuvw
Chopped root and
0.82bcdef 0.34qrst 0.18op 0.63bcdef 0.54efghijklmno 0.51ijklmnopqr
stem
Chopped leaf
0.38lmnopq 0.46nopq 0.48hijklmnop 0.82bcdefg 0.22nopq 0.33mnopqrstuvw
Whole root and
0.30nopq 0.70hij 1.21ab 0.79pqrs 0.43hijklmnopq 0.68cdefghijkl
stem
Whole leaf
1.07ab 0.0.77gh 1.09abcedf 0.18pqrs 0.29lmnop 0.18rstuvw
Cabbage cv.
Scorpio
Macerated root 0.48jklmnop 0.8efh 0.89abcdefghjk 0.67cdefghijk 0.52fghijklmnop 0.77uvw
and stem
Macerated leaf
0.76cdefghjk 1.03bc 1.21abc 0.56efghijklmno 1.01a 0.86bcdefg
Chopped root and
0.80bcdefg 0.90def 0.59fghjiklmnop 0.49fghijklmnopq 0.73abcdefgh 0.30opqrstuvw
stem
Chopped leaf
0.61efghijklm 0.63ijk 0.52ghijklmnop 1.07ab 0.14q 0.10tuvw
Whole root and
0.34mnoopq 0.27t 0.26nop 0.13s 0.56efghjiklm 0.07vw
stem
Whole leaf
0.53ghijklmn 0.24t 1.2abc 0.77bcdefg 0.40ijklmnopq 0.52hijklmnopq
Cabbage cv.
Rareball
Macerated root 0.54fghijklm 1.12b 1.25a 0.89bcde 0.64defghijk 0.41klmnopqrst
and stem
Macerated leaf
0.78cdefgh 1.03bc 0.72bcdefghijklmn 0.35jklmnopqrs 0.34jklmnopq 0.36lmnopqrstuvw
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
47
Appendix Table 7. Continued...
Chopped root and
046klmnopq 0.49lmno 0.97abcdefgh 0.47ghijklmnopqr 1.03a 0.47jklmnopqrs
stem
Chopped leaf
0.24opq 0.26t 0.98abcdefgh 0.47ghijklmnopqr 0.92abcd 0.25opqrstuvw
Whole root and
0.28q 0.24t
0.46hijklmnop 0.88bcde 0.98abc 0.88bcdef
stem
Whole leaf
0.2lmnopq 0.28st 1.23ab 0.95bcd 0.14q 0.19rstuvw
Radish
Macerated root 0.38ijklmnopq 0.23t 0.76abcdefghijklmn 0.95bcd 0.47hijklmnop 0.33mnopqrstuvw
and stem
Macerated leaf
0.48fghijklmn 0.41nopqrs 0.68defghjijklmno 0.20pqrs 1.00ab 0.35lmnopqrstuvw
Chopped root and
0.54abc 0.44nopq 0.88abcdefghijk 0.64defghijklm 0.68bcdefghi 0.83bcdefg
stem
Chopped leaf
1.05klmnopq 1.04bc 1.14abcde 0.52fghijklmnop 1.01a 0.97abc
Whole root and
0.47lmnopq 0.45nopq 0.28mnop 0.74cdefgh 0.86abcde 0.57fghijklmn
stem
Whole leaf
0.43lmnopq 0.52klmno 0.41jklmnop 0.33klmnopqrs 0.55efghijklm 0.65defghijklmn
Mustard
Macerated root
1.25a 1.29a 0.64efghijklmnop 0.74cdefgh 0.54efghijklmno 0.72cdefghijk
and stem
Macerated leaf
0.87bcde 0.33qrst 0.97abcdefgh 0.17qrs 0.24mnopq 0.19rstuvw
Chopped root and
1.03abc 0.85efg 1.03abcdefg 0.83bcdef 0.50hijklmnop 0.82bcdefghi
stem
Chopped leaf
0.59efghijklm 0.75ghi 0.37jlmnop 0.42hijklmnopqrs 0.96abcd 0.94abcd
Whole root and
1.02abc 1.01bcd 0.68cdefghijklmno 0.54efghijklmno 0.96abcd 0.40klmnopqrstu
stem
Whole leaf
0.85bcde 0.52klmno 0.40jklmnop 0.99bc 0.27lmnopq 0.82bcdefghi
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
48
Appendix Table 7. Continued...
Pechay
Macerated root 0.61efghijklm 0.95cde 0.81abcdefghijklm 0.73cdefghi 0.74abcdefgh 0.81bcdefghi
and stem
Macerated leaf
0.46klmnopq 0.43nopqr 1.20abcd 0.66cdefghijkl 0.84abcdef 1.21a
Chopped root and
0.34mnopq 0.27t 0.34lmnop 0.64defghijklm 0.37ijklmnopq 0.17stuvw
stem
Chopped leaf
0.47ghijklmno 0.48mnop 0.30mnop 0.56efghijklmno 0.54efghijklmno 0.34mnopqrstuvw
Whole root and
0.53cdefghi 0.52klmnop 0.27nop 0.65cdefghijkl 0.68bcdefghi 0.64defghijklm
stem
Whole leaf
0.77cdefghi 0.70hij 0.58fghijklmnop 0.69cdefghij 0.83abcdefg 0.90bcde
Radish +
mustard
Macerated root 0.44klmnopq 0.29st 0.39jklmnop 0.24opqrs 0.29lmnopq 0.61efghijklmno
and stem
Macerated leaf
0.59efghijklm 0.41opqrs 0.13p 0.78bcdefg 0.67cdefghij 0.36lmnopqrstuvw
Chopped root and
0.97bcd 1.05bc 0.31mnop 0.30mnopqrs 0.20pq 0.54ghijklmnop
stem
Chopped leaf
0.78cdefgh 0.63ijk 0.75abcdefghijklmn 0.59efghijklmn 0.42hijklmnopq 0.17stuvw
Whole root and
0.62efghijklm 0.61jklm 0.77abcdefghijklmn 0.62defghijklm 0.51ghijklmnop 0.68cdefghijkl
stem
Whole leaf
0.65efghjikl 0.61jkl 0.94abcdefghi 0.67cdefghijkl 0.51fghijklmnop 0.10tuvw
Untreated 0.95a 0.92a 0.93a 1.06a 1.23a 1.31a
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
AGUSTIN, FLORESCA T. MAY 2007. Evaluating the Biofumigation Potentials
of Various Brassica Species for the Control of Ralstonia solanacearum (E.F. Smith)
Yabuuchi et al. Affecting Potatoes. Benguet State University, La Trinidad, Benguet.
Adviser: Lily Ann D. Lando, PhD
ABSTRACT
The application of brassica reduced the population of Ralstonia solanacearum in
the soil with broccoli as the most effective biofumigant. However, the use of cabbage cv.
scorpio significantly reduced the bacterial population. The use of chopped leaves and
whole leaves effected the greatest reduction in the bacterial population. Among plant
tissues, leaves effected a higher reduction in R. solanacearum population. In reducing
bacterial population, the best combinations of biofumigant and tissue preparation were
chopped leaves of broccoli, whole leaves of cauliflower, macerated roots and stems of
cabbage cv. scorpio, and macerated leaves of mustard. The bacterial population in the
untreated soil increased continuously over the sampling period.
TABLE OF CONTENTS
Page
Bibliography. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
Table of Contents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
REVIEW OF LITERATURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
MATERIALS AND METHODS
Source of Test Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Preparation of Brassica Tissues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Evaluation of Bactericidal Potential of
Brassica Tissues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Laboratory Experiment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Data Gathered . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
RESULTS AND DISCUSSION
Effect of Biofumigant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Effect of Tissue Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Interaction Effect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
SUMMARY, CONCLUSIONS AND RECOMMENDATIONS . . . . . . . . . . . 22
LITERATURE CITED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
APPENDICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
ii
INTRODUCTION
Potato (Solanum tuberosum Linn.) ranks fourth among the most valuable crops
grown worldwide. It provides of low-cost energy to the human diet and is a good source
of carbohydrates, starch, proteins minerals, vitamins A and B2 and some elements such as
potassium and phosphorus (Kipps, 1979). In the Philippines, potato ranks third in
production among the leading commercial vegetable crops and first among the vegetables
in Northern Luzon. At present, 75% of the total production in the Cordillera region is
from the province of Benguet. The suitability of potato production in Benguet (1600-
2300 meters ASL) gives its estimated yield at 15.10 MT/ha (HARRDEC, 1996 as cited
by Lando, 2002). However, this is seldom met due to losses from the occurrence of pest
and diseases.
Bacterial wilt (BW) caused by Ralstonia solanacearum (E.F. Smith) Yabucchi et
al. is the most serious soil-borne disease of solanaceous crops such as potato, tobacco,
tomato and eggplant causing losses in quality and quantity of production (ACIAR, 2000).
Perez et al. (1997) have shown that the disease has become severe in the highland and
lowland potato production areas. R. solanacearum is capable of enduring in the soil and
has a wide host range (Urquhart and Mienie, 1997 as cited by Lando, 2002). The host
range includes 55 plant families especially members of Solanaceae.
Control measures are usually done through crop rotation, strict sanitation, use of
resistant cultivars, use of disease-free planting material, and minimum tillage.
Biofumigation using brassica tissues also decreases the incidence and severity of
bacterial wilt (ACIAR, 2000). However, using different combination of control measures
is more preferred to lessen the impact of the pathogen.
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
2
Biofumigation refers to the suppression of soil-borne pests and pathogens by
naturally-occurring biocidal compounds, principally isothiocyanates (ITCs), released into
the soil from decomposing organic material (ACIAR, 2000). Isothiocyanate compounds
are similar to the methyl isothiocyanate (MITC) toxin from the metham sodium soil
fumigant. These are highly biocidal to a diverse range of organisms including bacteria,
nematodes, fungi, insects, and germinating seeds (Brown and Morra, 1997; Kirkegaard et
al., 1994; Potter et al,, 1998 and Walker, 1997). Thus, biofumigation may provide an
option for farmers to manage BW based on their circumstances of disease pressure,
economics and their ideals for cropping system.
Bacterial wilt is difficult to manage because it is soil-borne and seed-borne and
there is no readily available chemical control. There is also great variation in the
bacterium often manifested in a wide host range. Severely infested soils are not planted to
potato anymore or are used in other industrial purposes. Thus, further reducing the
potential potato production.
Biofumigation potentially provide a sustainable disease control option, for
integrated BW management system while simultaneously improving soil health (soil
fertility). The incorporation of biofumigants into the soil provides valuable organic
matter, possibly reducing the dependence on organic fertilizers. Other benefits of
biofumigation include improved soil texture, increased water holding capacity and
improved microbial community structure (Harvey and Sams, 1999). The results of this
study would help seed companies to develop biofumigant-type crucifers. Finally would
open up opportunities in controlling other soil-borne pest and pathogens of other crop.
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
3
This study therefore aimed to evaluate the biofumigation potential of brassica for
the control of R. solanacearum population in the soil, identify the brassica which is most
effective biofumigant and determine the best method of brassica tissue preparation for
biofumigation.
The study was conducted at the Department of Plant Pathology Laboratory and
Greenhouse, Benguet State University, La Trinidad, Benguet from June to December
2005.
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
4
REVIEW OF LITERATURE
The Disease
Bacterial wilt (BW) is one of the most important, widespread and lethal bacterial
diseases of plants (Ma, 1990 as cited by Lando, 2002). It is considered a dreaded disease
in many parts of Asia, Africa, and Central and South America. In 2000, the Australia
Centre for International Agricultural Research (ACIAR) recognized it as one of the most
important diseases of bacterial origin in the world. Bacterial wilt is the number two
constraint on potato production in over 40 developing countries (CGIAR, 2005).
Hayward in 1985 reported that more than 55 crops and wild species are affected
by R. solanacearum crops such as potato, tobacco, tomato, eggplant, banana, chili, bell
pepper and peanut are highly susceptible to the disease. Recently it was shown that
certain ecotypes of the model plant Arabidopsis thaliana are also susceptible to the
pathogen (Hayward, 2000). An endemic strain (race 1, biovar 1) was detected in 2001 in
geraniums (Pelargonium sp.) in Florida, USA (Momol et al., 2003). It is common in
tropical, subtropical and warm temperature regions where temperature and moisture
conditions are favorable for its development (Singh, 1978). The bacterium may also be
present in cooler climates such as relatively high elevation in the tropics or higher
latitudes.
The Causal Organism
The bacterium responsible for bacterial wilt is Ralstonia solanacearum (E. F.
Smith) Yabucchi et al., (1996) formerly known as Pseudomonas solanacearum E. F.
Smith. It is a Gram negative, strictly aerobic, nospore-forming, noncapsulate, nitrate
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
5
reducing, catalase-positive, ammonia-forming, and monotrichous short rod (1.5 x 0.5
mm) (Sands et al., 1980; Stanier et al., 1966). The wild type bacterium is usually
nonmotile and does not form a polar flagellum in a liquid medium. Avirulent variants that
develop in culture are actively motile. Colonies on agar are opalescent which became
darker with age. Rich (1983) described them as small, irregular, smooth, wet and shiny.
The virulent colonies are pink in tetrazolium chloride agar (TCZA). The optimum
temperature for growth ranges from 350C- 370C (Weber, 1973 and Rich, 1983) and the
thermal death point lies at about 520C (Kerr, 1983).
R.
solanacearum cannot hydrolyze starch and it can liquefy gelatin slowly or not
at all. The bacterium is inhibited by relatively low concentrations of salt in broth culture
and is sensitive to desiccation.
The cultured bacterium in unaerated liquid media losses its virulence and viability
rapidly and change from the fluidal (nonmotile) wild type to the avirulent, highly motile
variants.
Symptoms
Bacterial wilt is described by Agrios (1997) as sudden wilt. Infected plants die
rapidly. Older leaves may first show leaf dropping and discoloration or one-sided wilting
and stunting before completely wilts and permanently dies. Severely infected tubers are
blackened and when cut, vascular ring turns brown. In general, the symptoms are wilting,
stunting and yellowing of the leaves, followed by the collapse of the entire plants
(Agrios, 1978).
Symptoms occur both above and belowground parts of the host plants. Above
ground symptoms include wilting, stunting, and yellowing of leaves. Infection is
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
6
characterized by initial wilting only of a part of the stems of the plant, or even one side of
the leaf or stem. The entire plant wilts quickly without yellowing when development of
the disease is rapid (French, 1996).
External symptoms on the tuber are visible at harvest when infection is severe.
Bacterial ooze collects at tuber eyes causing soil to adhere (CIP, 2004). Brownish
discolorations on the vascular rings are observed. When tubers are slightly squeezed,
ooze comes out naturally from the rings. In more advance stages of the disease
development, the vascular ring or the whole tuber may disintegrate completely (Bahar
and Danish, 1990; Martin and French, 1996).
Survival
Bacteria live in follow soil for 6 years or more and may persist indefinitely in the
presence of susceptible plants (Pope, 1995). R. solanacearum is capable of surviving
under high moisture. This proves the field observation that BW is more serious in wet,
humid, tropical areas than in desert areas, even under irrigation (Buddenhagen and
Kelman, 1964). However, survival depends on race involved and depends on deep soil
layer (Persley, 1995).
Management
French (1996) stated that the inherent variability of R. solanacearum and the
strong influence of environmental conditions on resistance make disease management
difficult. In managing the disease, crop rotation, prevention and use of resistant cultivars
are employed (Geesteranus as cited by Lando, 2002).
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
7
Using areas free of the bacterium reduces the chance of tubers of becoming
infected later. In a field infested with BW it takes at least 2 years rotation with non-
susceptible crops to decrease its population. Planting pathogen-free seed tubers will
decrease severity and incidence in infested field and will prevent the introduction of the
pathogen into non-infected area. The elimination of alternate hosts can decrease pathogen
population inoculum in the soil. The use of resistant cultivars play an important role but
the extreme variability found in R. solanacearum makes breeding for resistance to the
pathogen difficult (Sequeria, 1983).
Biofumigation
Biofumigation has been shown to reduce the levels of several soil pathogens,
including bacterial wilt and root knot nematode. Isothiocyanates (ITCs) were released
from brassica tissues when glucosinolates (GSLs) are hydrolyzed by endogenous
myrosinase enzyme (Angus et al., 1994). These hydrolysis products (ITCs) are known to
have broad biocidal activity including insecticidal, nematicidal, fungicidal, antibiotic and
phytotoxic effects (reviewed by Brown and Morra, 1997). The difference in structure of
individual GSLs and ITCs depends on their organic side-chain (aliphatic, aromatic or
indole). Their concentrations, profiles, distribution and toxicity varies within and between
brassica species and in different plant tissues, hence, the concentration and type of
biocidal hydrolysis product involved also varies (Kirkegaard and Sarwar, 1998).
Biofumigation is one of the newest technology as a component of integrated pest
management. Potential of brassicas (ITCs) were observed during the early 1990s when
wheat crops grew vigorously following brassica break crops such as canola and Indian
mustard than other break crops such as linseed or oats (Angus et al., 1991; Kirkegaard et
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
8
al., 1994). In the study of Kirkegaard et al. (1998), they grew wheat in pots inoculated
with the take-all fungus (Gaeumannomyces graminis var. tritici) and incorporated the
root residues of canola. Results showed lower take- all infection on wheat after brassicas
compared to linseed. Aromatic GSL present in canola roots have been shown to be highly
toxic to cereal fungal pathogens and genetic diversity within Australian canola varieties
allows selection of higher root GSL levels (Kirkegaard and Sarwar, 1999).
The work of Harding and Wicks (1999) shows that ITCs emanating from Brassica
juncea (Indian mustard) meal, B. juncea/B. napus (canola) leaves and roots are inhibitory
to a number of significant fungal pathogens of potato (Rhizoctonia AG3, Rhizoctonia AG8,
Verticillium dahliae (A and B), Colletotrichum coccodes (A and B), Phytophthora
erythroptica and P. coryptogea).
The preliminary studies on bacterial wilt caused by R. solanacearum indicate that
tissues of mustards (B. juncea, B. nigra and B. carimata) are more suppressive than those
of other brassicas tested suggesting that 2-propenyl GSL is the active compound (Akiew,
unpublished). This compound is also present in kale and cabbage indicating residues
from these crops may also have activity against BW. The results of the study of Akiew in
1999 demonstrate reductions of 40-80% in BW in the field by Indian mustard green
manure and up to 97% reduction in the glasshouse when combined with organic soil
amendments. A commercial Indian biofumigant (FUMUS) showed potential to reduce
levels of BW and increase potato yield dramatically (from 0.3-22 tons/ha) in an on-farm
trial in Victoria (ACIAR, 2000; Akiew et al., 1996).
In an experiment at Southedge Research Station BW nursery, Australia, the
radish, fodder rape and mustard biofumigants were all effective in delaying disease onset,
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
9
reducing the incidence and severity of BW and increasing eggplant yield (ACIAR, 2000).
Incorporation of some brassica fumigants has reduced BW by 50-60-% in three of the
four experiments of ACIAR in 2002 compared to non – brassica controls.
In north Queensland, Australia, results in some of the field trials have been
excellent. A paddock with high-level infection of bacterial wilt was planted with
tomatoes. An untreated block yielded less than two tons of tomatoes, while the area
where a brassica green manure treatment had been applied yielded up to 20 tons of
tomatoes and had correspondingly lower levels of bacterial wilt (Taylor, 2006).
In the Philippines, trials have been planted at a range of field sites, from high-
elevation areas in Benguet, with cabbages, potatoes and other temperate crops, down to
lowland areas in Mindanao, where eggplants and tomatoes are the major crops.
According to Kirkegaard (2006) the most promising treatments (radish, mustard and
broccoli) have reduced bacterial wilt significantly (50 to 60%) in most of the
experiments.
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
10
MATERIALS AND METHODS
Sources of Test Materials
Ralstonia solanacearum was isolated from naturally infected potatoes and pure
culture was prepared following standard procedures. Brassicas were collected from
the fields in Atok, Kabayan, La Trinidad, and Tuba, Benguet.
Preparation of Brassica Tissues
Brassica plants were collected. Soil was washed from the roots of all plants and
subsamples from each sample were separated into stem and root tissue and leaf tissue.
Macerated specimens were first cut into pieces then blended, chopped specimens were
cut into at least 2-3 cm long pieces and whole tissue specimens were used as is.
Each treatment was replicated thrice and arranged in a factorial completely
randomized design (CRD) with plant species as factor A and the different type of plant
tissue and method of preparation as factor B. The treatments were as follows:
Factor A Plant Species
A0 Untreated (Control 1)
A1 Sunflower - Control 2 (Tithonia diversifolia )
A2 Broccoli cv. Marathon (Brassica oleracea var. italica)
A3 Cauliflower cv. Milkyway (Brassica oleracea var. botrytis)
A4 Cabbage cv. Scorpio (Brassica oleracea var. capitata)
A5 Cabbage cv. Rareball (Brassica oleracea var. capitata)
A6 Radish cv. Mino early (Raphanus sativa)
A7 Mustard cv. Montana (Brassica juncea)
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
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A8 Pechay (Brassica pekenensis)
A9 Radish + Mustard (1:1)
Factor B Types of plant tissue and methods of preparation
B1 Macerated stems and roots
B2 Macerated leaves
B3 Chopped roots and stems
B4 Chopped leaves
B5 Whole roots and stems
B6 Whole leaves
Evaluation of the Bactericidal Potential of Brassica Tissues
Laboratory
Experiment. One hundred ml of bacterial suspension was incorporated
with 200 g sterile soil in plastic cups and allowed to stand for two days. A 10 - g soil
sample was then taken to determine initial population (cfu/g soil) of the bacterium and
Brassica tissues (10g/200g of soil) were incorporated. Bacterial population in the soil was
monitored weekly for five weeks following standard procedures.
Data Gathered
The following were the data gathered/computed:
1. Colony counts. Colonies that shows the typical characteristics of the
bacterium were counted.
2. cfu/g soil was calculated as follows:
average colony count x DF
amount plated
cfu/g soil= ---------------------------------------------
10 g soil
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
12
a. Initial population (cfu/g soil). The initial population of the bacterium in the
soil was measured two days after inoculation.
b. Weekly population (cfu/g soil). Soil samples were obtained from the
treatments every week for five weeks.
c. Final population (cfu/g soil). Final population was taken on the fifth week
from inoculation.
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
13
RESULTS AND DISCUSSIONS
Effect of Biofumigant
After seven days from incorporation, the brassica biofumigants had an immediate
effect in reducing the Ralstonia solanacearum population except for sunflower, cabbage
and pechay in which there was an increase in bacterial population (Table 1). Generally,
the bacterial population decreases with the application of biofumigants, however there
were slight increase observed during the second to the fourth assessment period. Results
revealed that the application of broccoli consistently decrease R. solanacearum
population in the soil. On the other hand, the bacterial population in the soil treated with
pechay consistently increase. On the final week, there was a decrease in R. solanacearum
population in most of the treatments. Greatest reduction in bacterial population was
observed in the soil treated with broccoli followed by cabbage cv. scorpio, radish +
mustard, cabbage cv. rareball and cauliflower (Figure 1). There was an increase in
bacterial population in the untreated soil and the soil treated with pechay and radish. This
shows that pechay had no impact in reducing R. solanacearum population. Pechay
decomposed much faster than the other biofumigants. The ease by which pechay
decomposed may have caused the release of ITC’s much faster than the other treatments,
thereby causing the faster dissipation of any biofumigant content. It was also the findings
of ACIAR that pechay had no effect on the reduction of R. solanacearum population. The
application of radish show a negative effect in the reduction of bacterial population, this
proves that GSL content varies within brassica varieties (ACIAR, 2000).
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
14
Table 1. Effect of biofumigant on the population of R. solanacearum (log cfu x 104)
BIOFUMIGANT ASSESSMENT
PERIOD
Initial
Week 1
Week 2
Week 3
Week 4
Week 5
Sunflower
0.6bc 0.76a 0.84ab 0.61ab 0.54c 0.52bc
Broccoli
0.61bc 0.52b 0.43d 0.41c 0.32d 0.29e
Cauliflower
0.68b 0.57b 0.67bc 0.55ab 0.38d 0.44cd
Cabbage cv. Scorpio
0.59bc 0.66ab 0.78ab 0.62ab 0.56bc 0.32de
Cabbage cv. Rareball
0.42d 0.57b 0.94a 0.67a 0.68ab 0.43cd
Radish
0.56c 0.52b 0.69bc 0.56ab 0.77a 0.62ab
Mustard
0.94a 0.79a 0.68bc 0.62ab 0.58bc 0.65a
Pechay
0.53c 0.56b 0.59cd 0.66ab 0.67ab 0.68a
Radish + Mustard
0.68b 0.6b 0.55cd 0.54b 0.43d 0.41cd
Untreated
0.95a 0.92a 0.93a 1.06a 1.23a 1.31a
The ITCs produced vary between brassica species and toxicity may sometimes
differ among organisms (Brown and Morra, 1997). The level of glucosinolates in broccoli
is higher than in other crucifers and was highly biocidal to a diverse range of organisms
including nematodes, bacteria, fungi, insects and germinating seeds (Kirkegaard et al.,
1994 and Brown and Morra, 1997). The positive effect of sunflower show, on the other
hand, that even nonbrassicaceous organic matter may reduce R. solanacearum
population. This may point to other non GSL-related effects caused by the decomposing
organic matter.
Guilabo (2005) stated that broccoli and cauliflower decreased the population of R.
solanacearum in the soil. In addition the application of cauliflower effectively reduced
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
15
bacterial wilt incidence. Furthermore, Akiew (1999) cited that the application of mustard
reduced bacterial wilt at 40-80 %. According to the ACIAR project on biofumigation the
most promising brassica tested in the Philippines (using radish, mustard and broccoli)
have reduced bacterial wilt by 50 to 60 %. The reduction in bacterial population reduces
the inoculum in the soil and will in turn reduce the incidence and severity of disease.
WEEK1
WEEK5
Untreated
0.92
1.31
0.41
Radish + Mustard
0.6
Pechay
0.56 0.68
0.65
Mustard
0.79
Radish
0.520.62
0.43
Cabbage cv. Rareball
0.57
0.32
Cabbage cv. Scorpio
0.66
0.44
Cauliflower
0.57
0.29
Broccoli
0.52
0.52
Sunflower
0.76
0
0.2
0.4
0.6
0.8
1
1.2
1.4
log cfu/g soil
Figure 1. The change in the R. solanacearum population in the soil as affected by the
biofumigants (week 1 and week 5)
Effect of Tissue Preparation
Generally, there was an increase in the population of Ralstonia solanacearum
after seven days of incorporating biofumigants. However, immediate reduction in
bacterial population was observed with the use of chopped roots and stems and whole
leaves. The general trend from week 2 to week 4 was decrease of bacterial population
although in some treatments there was a slight increase in population. On the final week,
all the treatments had reduced R. solanacearum population in the soil (Table 2). The
greatest reduction was effected by the application of chopped leaves but was not
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
16
significantly different from the use of whole leaves. Between the root and stem and leaf
tissues, the leaf tissue effected the higher reduction of bacterial population (Figure 2).
The leaves decomposed faster than the roots and stems, thus production of ITCs is also
faster.
Table 2. Effect of tissue type and preparation on the population of R. solanacearum (log
cfu x 104)
TISSUE TYPE
ASSESSMENT PERIOD
AND
Initial
Week 1
Week 2
Week 3
Week 4
Week 5
PREPARATION
Macerated roots and
stems 0.54c 0.68ab 0.73a 0.63ab 0.53a 0.51ab
Macerated leaves
0.68ab 0.71a 0.76a 0.47c 0.55a 0.52ab
Chopped roots and
stems 0.75a 0.64ab 0.64ab 0.66a 0.55a 0.55a
Chopped leaves
0.58c 0.6abc 0.63ab 0.59ab 0.59a 0.38c
Whole roots and
stems 0.51c 0.56bc 0.57b 0.53bc 0.63a 0.51ab
Whole leaves
0.68ab 0.51c 0.79a 0.59ab 0.47b 0.44bc
In general, green fresh leaf residues of brassica incorporated in the soil released
greater amounts of ITCs and may suppress pests better than the dried or mature residues
as those found in roots and stems. As Matthiessen et al. (2001) noted, aromatic ITCs
produced from GSLs often found in roots are very toxic but they are of low volatility and
that contact with organisms may be reduced. Aliphatic ITCs found mostly on shoots are
less toxic but of greater volatility that allow easier contact with organisms. As shoot is
generally very much greater than root biomass, shoots contribute more of the total ITC
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
17
potential (Matthiessen and Kirkegaard, 1998). ACIAR Project No. SMCN/200/114 points
out that tissue disruption increases the efficiency of release of ITCs achieved by rough
chopping and blending/ macerating. By chopping the plant cells, the vacuoles in which
the GSLs are stored were destroyed and able to meet the myrosinase enzyme in the
cytoplasm. However, macerated plant tissues in this experiment show a lower reduction
in the bacterial population compared to chopped and whole plant tissues. This was maybe
due to faster loss of isothiocyanates. Longer-term incubation (30 days) of tissues that
were not macerated can sometimes effective as macerated amendments against BW
(ACIAR, 2000). ACIAR (2000) thus concluded, “The general longer-term impacts of
organic amendments can also play a role in pest suppression presumably due to induced
changes in the soil microbial community favoring pest antagonist”.
WEEK1
WEEK5
0.44
Whole leaves
0.51
0.51
Whole roots and stems
0.56
0.38
Chopped leaves
0.6
0.55
Chopped roots & stems
0.64
0.52
Macerated leaves
0.71
0.51
Macerated roots & stems
0.68
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
log cfu/g soil
Figure 2. The change in the R. solanacearum population in the soil as affected by the
tissue preparation (week 1 and week 5)
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
18
Interaction Effect
Figure 3 shows the decrease in the population of R. solanacearum in the selected
best combinations of biofumigants and tissue preparation. The use of chopped leaves of
broccoli, whole leaves of cauliflower, macerated roots of cabbage cv. scorpio, macerated
leaves of mustard, whole leaves and chopped leaves of radish + mustard effected the
greatest reduction. The summary of the changes in the population of R. solanacearum
was presented in Figure 5.
WEEK1
WEEK5
0.17
chopped leaves of radish + mustard
0.64
0.11
whole leaves of radish + mustard
0.61
0.19
macerated leaves of mustard
0.33
macerated roots and stems of
0.08
0.88
cabbage cv. scorpio
0.19
whole leaves of cauliflower
0.77
0.05
chopped leaves of broccoli
0.31
0
0.2
0.4
0.6
0.8
1
log cfu/g soil
Figure 3. Decrease in the population of R. solanacearum in the selected best
combinations of biofumigant and tissue preparation
The greatest increase in the bacterial population was observed in untreated soil, and in
soil treated with whole roots and stems of cabbage cv. rareball, macerated roots and
stems of sunflower, chopped roots and stems of sunflower, macerated leaves and whole
leaves of pechay (Figure 4). The GSL types and concentrations vary within and between
brassica species and in the different plant tissues (Brown and Morra, 1997). It is also
affected by age, health and nutrition and edaphic environment in which tissues are
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
19
incorporated. The nutrients supplied to the plant during its growth affects the level of
GSL. Efficiency of release of ITCs from incorporated tissues is also influence by the type
of soil, moisture content and degree of tissue disruption.
These results further indicate the potential use of biofumigation for the control of
Ralstonia solanacearum. The range in glucosinolate profiles, the differential toxicity of
isothiocynate to different pest and the wide range in phenological and morphological
diversity in brassica provides significant scope to select or breed brassicas with enhanced
biofumigation potential for a particular target organism (Kirkegaard et. al., 1998).
WEEK1
WEEK5
1.31
untreated
0.92
0.91
whole leaves of pechay
0.7
1.21
macerated leaves of pechay
0.43
whole roots and stems of cabbage
0.88
0.24
cv. rareball
chopped roots and stems of
1.09
0.93
sunflower
macerated roots and stems of
0.75
0.51
sunflower
0
0.2 0.4 0.6 0.8
1
1.2 1.4
log cfu/g soil
Figure 4. The greatest increase in the population of R. solanacearum as affected by the
combinations of biofumigant and tissue preparation
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
20
SUNFLOWER
WEEK1
WEEK5
1.31
Untreated
0.92
0.2
Whole leaves
0.63
0.16
Whole roots and stems
0.41
0.28
Chopped leaves
0.81
1.09
Chopped roots & stems
0.93
0.66
Macerated leaves
1.24
0.75
Macerated roots & stems
0.51
0
0.2
0.4
0.6
0.8
1
1.2
1.4
log cfu/g soil
BROCCOLI
WEEK1
WEEK5 CAULIFLOWER
WEEK1
WEEK5
0.92
1.31
0.92
1.31
0.34
0.39
0.19
0.77
0.45
0.82
0.7
0.68
0.05
0.33
0.31
0.46
0.2
0.51
0.48
0.34
0.33
0.36
0.85
0.61
0.55
0.3
0.34
0.55
0
0.5
1
1.5
0
0.5
1
1.5
log cfu/g soil
log cfu/g soil
CABBAGE cv. SCORPIO
WEEK5
CABBAGE cv. RAREBALL
WEEK5
WEEK1
WEEK1
0.92
1.31
0.92
1.31
0.24
0.52
0.
0.19 29
0.07
0.88
0.27
0.24
0.1
0.26
0.63
0.26
0.3
0.47
0.9
0.49
0.86
0.36
1.03
1.03
0.08
0.42
0.88
1.12
0
0.5
1
1.5
0
0.5
1
1.5
log cfu/g soil
log cfu/g soil
Figure 5a. Summary of the changes in the population of R. solanacearum as affected by
the biofumigant and tissue preparation
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
21
RADISH
WEEK1
WEEK5
MUSTARD
WEEK1
WEEK5
1.31
0.92
1.31
0.92
0.520.65
0.52
0.82
0.450.57
0.4
1.01
1.04
0.98
0.75 0.95
0.44
0.83
0.85
0.82
0.41
0.36
0.33
0.19
0.230.33
0.72
1.29
0
0.5
1
1.5
0
0.5
1
1.5
log cfu/g soil
log cfu/g soil
PECHAY
WEEK1
WEEK5
RADISH + MUSTARD
WEEK5
WEEK1
0.92
1.31
0.92
1.31
0.7
0.91
0.11
0.61
0.520.65
0.61
0.68
0. 0.48
35
0.17
0.64
0. 0.27
17
0.54
1.05
0.37
0.43
1.21
0.41
0.
0.62
0.
81 95
0.29
0
0.5
1
1.5
0
0.5
1
1.5
log cfu/g soil
log cfu/g soil
Figure. 5b. Summary of the changes in the population of R. solanacearum as affected by
the biofumigant and tissue preparation
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
22
SUMMARY, CONCLUSIONS AND RECOMMENDATIONS
Summary
The study was conducted at the laboratory and greenhouse of the Department of
Plant Pathology, Benguet State University, La Trinidad, Benguet to evaluate the
biofumigation potentials of various brassica species for the control of Ralstonia
solanacearum (E. F. Smith) Yabuuchi et al. affecting potatoes.
Results showed that the application of brassica can effectively reduce the
population of Ralstonia solanacearum in the soil with broccoli as the most effective
biofumigant. However, the use of cabbage cv. scorpio significantly reduces the bacterial
population. The use of chopped leaves and whole leaves effected the greatest reduction in
the bacterial population. Among plant tissues, leaves effected a higher reduction in R.
solanacearum population. In reducing bacterial population, the best combinations of
biofumigant and tissue preparation were chopped leaves of broccoli, whole leaves of
cauliflower, macerated roots and stems of cabbage cv. scorpio, and macerated leaves of
mustard. The bacterial population in the untreated soil continuously increased throughout
the sampling period.
Conclusions
Based on the findings of this study, biofumigants can be used to reduce the soil
population of Ralstonia solanacearum. Furthermore, the incorporation of brassicaceous
“waste” material is an economical and environmentally-safe practice that can be used by
resource-poor farmers. Finally, the use of cruciferous biofumigants can be a viable
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
23
option in an integrated and long-term management of bacterial wilt disease both in
conventional and in organic production systems.
Recommendations
The following are hereby recommended:
1. A follow-up study to confirm these results must be conducted.
2. A farm trial must be conducted to evaluate the efficacy of using biofumigants
for the control of R. solanacearum in the field.
3. A study should be conducted to determine the effect of biofumigants to other
soilborne pathogens.
4. Finally, inclusion of biofumigants in integrated bacterial wilt management
should be considered.
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
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solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
26
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White). Vol. 1. Pp. 364 – 370.
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Australia. Pp. 5 - 7.
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Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
27
APPENDICES
Appendix Table 1. Initial population of Ralstonia solanacearum in the soil (log cfu/g soil
x 104)
REPLICATION
TREATMENT I
II
III TOTAL MEAN
Sunflower
Macerated root + stem
0.52 0.32 0.4 1.24
0.41
Macerated leaf
0.34 0.49 0.68 1.51
0.50
Chopped root + stem
0.81 0.86 0.91 2.58
0.86
Chopped leaf
0.67 0.58 0.74 1.99
0.66
Whole root + stem
0.56 0.43 0.32 1.31
0.44
Whole leaf
0.4 0.94 0.81 2.15
0.72
Broccoli
Macerated root + stem
0.36 0.11 0.2 0.67
0.22
Macerated leaf
0.66 0.59 0.64 1.89
0.63
Chopped root + stem
0.92 0.85 1.14 2.91
0.97
Chopped leaf
0.77 0.2 0.23 1.2
0.40
Whole root + stem
0.7 0.41 0.67 1.78
0.59
Whole leaf
0.6 0.95 1.01 2.56
0.85
Cauliflower
Macerated root + stem
0.4 0.68 0.45 1.53
0.51
Macerated leaf
1.15 1.06 0.61 2.82
0.94
Chopped root + stem
0.88 0.87 0.72 2.47
0.82
Chopped leaf
0.3 0.32 0.53 1.15
0.38
Whole root + stem
0.18 0.32 0.4 0.9
0.30
Whole leaf
1.03 1.1 1.09 3.22
1.07
Cabbage cv. Scorpio
Macerated root + stem
0.67 0.36 0.4 1.43
0.48
Macerated leaf
0.8 0.49 1 2.29
0.76
Chopped root + stem
0.8 0.68 0.91 2.39
0.80
Chopped leaf
0.79 0.57 0.46 1.82
0.61
Whole root + stem
0.32 0.28 0.43 1.03
0.34
Whole leaf
0.64 0.45 0.51 1.6
0.53
Cabbage cv. Rareball
Macerated root + stem
0.48 0.38 0.76 1.62
0.54
Macerated leaf
0.51 0.95 0.87 2.33
0.78
Chopped root + stem
0.38 0.48 0.52 1.38
0.46
Chopped leaf
0.08 0.38 0.26 0.72
0.24
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
28
Appendix Table 1. Continued...
REPLICATION
TREATMENT I
II
III TOTAL MEAN
Whole root + stem
0.36 0.2 0.28 0.84
0.28
Whole leaf
0.11 0.2 0.32 0.63
0.21
Radish
Macerated root + stem
0.43 0.32 0.38 1.13 0.38
Macerated leaf
0.45 0.54 0.45 1.44 0.48
Chopped root + stem
0.41 0.58 0.62 1.61 0.54
Chopped leaf
0.93 1.13 1.08 3.14 1.05
Whole root + stem
0.32 0.57 0.52 1.41 0.47
Whole leaf
0.51 0.34 0.43 1.28 0.43
Mustard
Macerated root + stem
1.45 1.06 1.23 3.74 1.25
Macerated leaf
0.91 0.79 0.9 2.6
0.87
Chopped root + stem
0.95 1.06 1.09 3.1
1.03
Chopped leaf
0.81 0.43 0.54 1.78 0.59
Whole root + stem
1.07 1 0.99
3.06 1.02
Whole leaf
0.91 0.97 0.68 2.56 0.85
Pechay
Macerated root + stem
0.68 0.57 0.58 1.83 0.61
Macerated leaf
0.49 0.41 0.48 1.38 0.46
Chopped root + stem
0.4 0.26 0.36 1.02 0.34
Chopped leaf
0.45 0.48 0.49 1.42 0.47
Whole root + stem
0.69 0.56 0.34 1.59 0.53
Whole leaf
1 0.82
0.48 2.3 0.77
Radish + mustard
Macerated root + stem
0.67 0.32 0.32 1.31 0.44
Macerated leaf
0.62 0.63 0.53 1.78 0.59
Chopped root + stem
1.08 0.84 0.99 2.91 0.97
Chopped leaf
0.95 0.51 0.88 2.34 0.78
Whole root + stem
0.73 0.49 0.68 1.9
0.63
Whole leaf
0.71 0.6 0.63 1.94 0.65
Untreated
0.9
1.01 0.94 2.85 0.95
TOTAL
34.81 31.78 33.94 100.53
MEAN
0.65 0.59 0.63
0.62
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
29
ANOVA TABLE
SOURCE OF DF SS MS FC Tab F
VARIATION 0.05 0.01
Factor A
8
2.90
0.36
16.92**
2.03
2.69
Factor B
5
1.21
0.24
11.33**
2.3
3.2
A x B
40
5.65
0.14
6.59**
1.51
1.79
Error 108
2.32
0.02
TOTAL 161 12.08
CV = 29.35%
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
30
Appendix Table 2. Week one population of Ralstonia solanacearum in the soil (log cfu/g
soil x 104)
REPLICATION
TREATMENT I
II
III TOTAL MEAN
Sunflower
Macerated root + stem
0.46 0.48 0.58 1.52
0.51
Macerated leaf
0.96 1.51 1.26 3.73
1.24
Chopped root + stem
0.76 1.01 1.03 2.8
0.93
Chopped leaf
0.6 0.81 1.03 2.44
0.81
Whole root + stem
0.3 0.61 0.32 1.23
0.41
Whole leaf
0.18 0.93 0.78 1.89
0.63
Broccoli
Macerated root + stem
0.15 0.3 0.45 0.9
0.30
Macerated leaf
0.72 0.79 1.05 2.56
0.85
Chopped root + stem
0.36 0.4 0.67 1.43
0.48
Chopped leaf
0.3 0.26 0.36 0.92
0.31
Whole root + stem
0.45 1.03 0.98 2.46
0.82
Whole leaf
0.26 0.28 0.49 1.03
0.34
Cauliflower
Macerated root + stem
0.46 0.58 0.6 1.64
0.55
Macerated leaf
0.59 0.72 0.51 1.82
0.61
Chopped root + stem
0.32 0.28 0.43 1.03
0.34
Chopped leaf
0.34 0.46 0.57 1.37
0.46
Whole root + stem
0.58 0.62 0.91 2.11
0.70
Whole leaf
0.79 0.92 0.59 2.3
0.77
Cabbage cv. Scorpio
Macerated root + stem
1.32 0.34 0.97 2.63
0.88
Macerated leaf
1.43 0.88 0.79 3.1
1.03
Chopped root + stem
0.92 0.76 1.01 2.69
0.90
Chopped leaf
0.88 0.58 0.43 1.89
0.63
Whole root + stem
0.11 0.4 0.3 0.81
0.27
Whole leaf
0.08 0.26 0.38 0.72
0.24
Cabbage cv. Rareball
Macerated root + stem
0.84 1.25 1.27 3.36
1.12
Macerated leaf
1.38 1.19 0.51 3.08
1.03
Chopped root + stem
0.32 0.51 0.65 1.48
0.49
Chopped leaf
0.28 0.28 0.23 0.79
0.26
Whole root + stem
0.11 0.2 0.4 0.71
0.24
Whole leaf
0.18 0.45 0.23 0.86
0.29
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
31
Appendix Table 2. Continued...
REPLICATION
TREATMENT I
II
III TOTAL MEAN
Radish
Macerated root + stem
0.23 0.15 0.3 0.68 0.23
Macerated leaf
0.26 0.58 0.4 1.24 0.41
Chopped root + stem
0.45 0.54 0.34 1.33 0.44
Chopped leaf
0.99 1.05 1.09 3.13 1.04
Whole root + stem
0.49 0.41 0.46 1.36 0.45
Whole leaf
0.52 0.61 0.43 1.56 0.52
Mustard
Macerated root + stem
1.29 1.32 1.27 3.88 1.29
Macerated leaf
0.3 0.41 0.28 0.99 0.33
Chopped root + stem
0.6 0.95 1.01 2.56 0.85
Chopped leaf
0.63 1.03 0.59 2.25 0.75
Whole root + stem
1.37 0.78 0.88 3.03 1.01
Whole leaf
0.43 0.45 0.68 1.56 0.52
Pechay
Macerated root + stem
0.9 1.03 0.92 2.85 0.95
Macerated leaf
0.3 0.59 0.41 1.3 0.43
Chopped root + stem
0.36 0.26 0.18 0.8
0.27
Chopped leaf
0.45 0.46 0.52 1.43 0.48
Whole root + stem
0.7 0.32 0.53 1.55 0.52
Whole leaf
0.86 0.72 0.52 2.1
0.70
Radish + mustard
Macerated root + stem
0.15 0.32 0.41 0.88 0.29
Macerated leaf
0.38 0.49 0.36 1.23 0.41
Chopped root + stem
0.86 1 1.28
3.14 1.05
Chopped leaf
0.08 0.34 1.49 1.91 0.64
Whole root + stem
0.59 0.64 0.59 1.82 0.61
Whole leaf
0.69 0.53 0.62 1.84 0.61
Untreated
0.88 1.24 0.63 2.75 0.92
TOTAL
27.56 30.75 30.59 88.9
MEAN
0.51 0.57 0.57
0.55
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
32
ANOVA TABLE
SOURCE OF DF SS MS FC Tab F
VARIATION 0.05 0.01
Factor
A 8 1.44 0.18
3.92** 2.03 2.69
Factor B
5
0.72
0.14
3.14*
2.3
3.2
A x B
40
10.92
0.27
5.94**
1.51
1.79
Error 108
4.96 0.05
TOTAL 161 18.05
CV = 34.82%
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
33
Appendix Table 3. Week two population of Ralstonia solanacearum in the soil (log cfu/g
soil x 104)
REPLICATION
TREATMENT I
II
III TOTAL MEAN
Sunflower
Macerated root + stem
1.27 1.18 1.1 3.55
1.18
Macerated leaf
0.71 0.76 0.67 2.14
0.71
Chopped root + stem
0.82 1.08 0.86 2.76
0.92
Chopped leaf
0.86 1.09 0.64 2.59
0.86
Whole root + stem
0.41 0.38 0.89 1.68
0.56
Whole leaf
0.11 0.2 0.2 0.51
0.17
Broccoli
Macerated root + stem
0.32 0.15 0.36 0.83
0.28
Macerated leaf
0.74 0.36 0.3 1.4
0.47
Chopped root + stem
0.23 1.08 0.3 1.61
0.54
Chopped leaf
0.4 0.11 0.26 0.77
0.26
Whole root + stem
0.4 0.36 1.17 1.93
0.64
Whole leaf
0.41 0.3 0.56 1.27
0.42
Cauliflower
Macerated root + stem
0.15 0.28 0.59 1.02
0.34
Macerated leaf
0.53 0.7 0.93 2.16
0.72
Chopped root + stem
0.15 0.11 0.3 0.56
0.19
Chopped leaf
0.28 0.56 0.61 1.45
0.48
Whole root + stem
1.15 1.29 1.21 3.65
1.22
Whole leaf
1.21 1.15 0.92 3.28
1.09
Cabbage cv. Scorpio
Macerated root + stem
0.64 1.06 0.99 2.69
0.90
Macerated leaf
1.25 1.09 1.29 3.63
1.21
Chopped root + stem
0.89 0.36 0.52 1.77
0.59
Chopped leaf
0.91 0.4 0.26 1.57
0.52
Whole root + stem
0.08 0.41 0.3 0.79
0.26
Whole leaf
1.19 1.14 1.29 3.62
1.21
Cabbage cv. Rareball
Macerated root + stem
1.24 1.28 1.23 3.75
1.25
Macerated leaf
0.64 0.97 0.56 2.17
0.72
Chopped root + stem
0.71 1.13 1.08 2.92
0.97
Chopped leaf
0.86 0.9 1.18 2.94
0.98
Whole root + stem
0.52 0.53 0.34 1.39
0.46
Whole leaf
1.3 1.45 0.96 3.71
1.24
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
34
Appendix Table 3. Continued...
REPLICATION
TREATMENT I
II
III TOTAL MEAN
Radish
Macerated root + stem
0.81 0.76 0.72 2.29 0.76
Macerated leaf
0.83 0.6 0.6 2.03 0.68
Chopped root + stem
0.84 0.89 0.91 2.64 0.88
Chopped leaf
1.04 1.3 1.09 3.43 1.14
Whole root + stem
0.34 0.2 0.32 0.86 0.29
Whole leaf
0.56 0.38 0.3 1.24 0.41
Mustard
Macerated root + stem
0.72 0.69 0.51 1.92 0.64
Macerated leaf
1.04 1.08 0.79 2.91 0.97
Chopped root + stem
0.74 1.23 1.1 3.07 1.02
Chopped leaf
0.28 0.18 0.67 1.13 0.38
Whole root + stem
0.82 0.9 0.34 2.06 0.69
Whole leaf
0.79 0.26 0.15 1.2
0.40
Pechay
Macerated root + stem
0.74 0.8 0.9 2.44 0.81
Macerated leaf
1.24 1.06 1.3 3.6
1.20
Chopped root + stem
0.08 0.91 0.04 1.03 0.34
Chopped leaf
0.36 0.26 0.28 0.9
0.30
Whole root + stem
0.15 0.3 0.38 0.83 0.28
Whole leaf
0.87 0.51 0.36 1.74 0.58
Radish + mustard
Macerated root + stem
0.23 0.56 0.4 1.19 0.40
Macerated leaf
0.15 0.04 0.2 0.39 0.13
Chopped root + stem
0.41 0.26 0.26 0.93 0.31
Chopped leaf
1.25 0.4 0.61 2.26 0.75
Whole root + stem
0.54 0.63 1.13 2.3
0.77
Whole leaf
1.21 0.97 0.66 2.84 0.95
Untreated
0.89 1.21 0.7 2.8
0.93
TOTAL
36.42 37.03 35.89 109.34
MEAN
0.67 0.69 0.66
0.67
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
35
ANOVA TABLE
SOURCE OF DF SS MS FC Tab F
VARIATION 0.05 0.01
Factor A
8
3.37
0.42
6.15**
2.03
2.69
Factor B
5
0.93
0.19
2.72*
2.3
3.2
A x B
40
12.37
0.31
4.52**
1.51
1.79
Error 108
7.39 0.07
TOTAL 161 24.05
CV = 38.18%
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
36
Appendix Table 4. Week three population of Ralstonia solanacearum in the soil (log
cfu/g soil x 104)
REPLICATION
TREATMENT I
II
III TOTAL MEAN
Sunflower
Macerated root + stem
0.38 0.4 0.38 1.16
0.39
Macerated leaf
0.53 0.75 0.43 1.71
0.57
Chopped root + stem
1.29 1.34 1.29 3.92
1.31
Chopped leaf
0.84 0.75 0.43 2.02
0.67
Whole root + stem
0.08 0.04 0.28 0.4
0.13
Whole leaf
0.58 1.04 0.08 1.7
0.57
Broccoli
Macerated root + stem
0.61 0.86 0.7 2.17
0.72
Macerated leaf
0.41 0.45 0.41 1.27
0.42
Chopped root + stem
0.4 0.95 0.58 1.93
0.64
Chopped leaf
0.08 0.23 0.3 0.61
0.20
Whole root + stem
0.34 0.08 0.43 0.85
0.28
Whole leaf
0.34 0.15 0.08 0.57
0.19
Cauliflower
Macerated root + stem
0.18 0.36 0.43 0.97
0.32
Macerated leaf
0.85 0.64 0.15 1.64
0.55
Chopped root + stem
0.26 0.6 1.05 1.91
0.64
Chopped leaf
0.94 0.94 0.59 2.47
0.82
Whole root + stem
0.71 0.92 0.75 2.38
0.79
Whole leaf
0.15 0.2 0.2 0.55
0.18
Cabbage cv. Scorpio
Macerated root + stem
0.63 0.82 0.57 2.02
0.67
Macerated leaf
0.61 0.74 0.34 1.69
0.56
Chopped root + stem
0.4 0.64 0.43 1.47
0.49
Chopped leaf
0.97 1.31 0.95 3.23
1.08
Whole root + stem
0.08 0.15 0.15 0.38
0.13
Whole leaf
0.69 0.83 0.81 2.33
0.78
Cabbage cv. Rareball
Macerated root + stem
0.87 0.85 0.95 2.67
0.89
Macerated leaf
0.3 0.23 0.53 1.06
0.35
Chopped root + stem
0.41 0.4 0.6 1.41
0.47
Chopped leaf
0.41 0.6 0.4 1.41
0.47
Whole root + stem
0.98 0.81 0.85 2.64
0.88
Whole leaf
0.99 0.91 0.96 2.86
0.95
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
37
Appendix Table 4. Continued...
REPLICATION
TREATMENT I
II
III TOTAL MEAN
Radish
Macerated root + stem
0.95 0.92 0.98 2.85
0.95
Macerated leaf
0.11 0.26 0.23 0.6
0.20
Chopped root + stem
0.61 0.74 0.56 1.91
0.64
Chopped leaf
0.57 0.57 0.41 1.55
0.52
Whole root + stem
0.71 0.78 0.73 2.22
0.74
Whole leaf
0.36 0.32 0.32 1
0.33
Mustard
Macerated root + stem
0.73 0.72 0.78 2.23
0.74
Macerated leaf
0.18 0.2 0.15 0.53 0.18
Chopped root + stem
0.77 0.85 0.88 2.5
0.83
Chopped leaf
0.23 0.15 0.87 1.25
0.42
Whole root + stem
0.28 0.64 0.72 1.64
0.55
Whole leaf
0.87 1.03 1.07 2.97
0.99
Pechay
Macerated root + stem
0.58 0.81 0.8 2.19 0.73
Macerated leaf
0.43 0.56 1 1.99
0.66
Chopped root + stem
0.72 0.52 0.67 1.91
0.64
Chopped leaf
0.58 0.59 0.51 1.68
0.56
Whole root + stem
0.66 0.73 0.57 1.96
0.65
Whole leaf
0.78 0.67 0.62 2.07
0.69
Radish + mustard
Macerated root + stem
0.26 0.28 0.2 0.74 0.25
Macerated leaf
0.58 0.69 1.07 2.34
0.78
Chopped root + stem
0.45 0.2 0.26 0.91 0.30
Chopped leaf
0.71 0.68 0.4 1.79 0.60
Whole root + stem
0.68 0.8 0.4 1.88 0.63
Whole leaf
0.58 0.7 0.72 2
0.67
Untreated
1.26 1.2 0.72 3.18 1.06
TOTAL
29.69 33.4 31.02 94.11
MEAN
0.55 0.62 0.57
0.58
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
38
ANOVA TABLE
SOURCE OF DF SS MS FC Tab F
VARIATION 0.05 0.01
Factor A
8
0.88
0.11
3.78**
2.03
2.69
Factor B
5
0.62
0.12
4.28**
2.3
3.2
A x B
40
9.19
0.23
7.91**
1.51
1.79
Error 108
3.14
0.03
TOTAL
161
13.83
CV = 29.35%
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
39
Appendix Table 5. Week four population of Ralstonia solanacearum in the soil (log cfu/g
soil x 104)
REPLICATION
TREATMENT I
II
III TOTAL MEAN
Sunflower
Macerated root + stem
0.48 0.73 0.81 2.02
0.67
Macerated leaf
0.4 0.28 0.58 1.26
0.42
Chopped root + stem
0.41 0.6 0.78 1.79
0.60
Chopped leaf
1.05 0.91 0.63 2.59
0.86
Whole root + stem
0.28 0.36 0.04 0.68
0.23
Whole leaf
0.8 0.36 0.26 1.42
0.47
Broccoli
Macerated root + stem
0.26 0.34 0.3 0.9
0.30
Macerated leaf
0.26 0.2 0.2 0.66
0.22
Chopped root + stem
0.43 0.34 0.2 0.97
0.32
Chopped leaf
0.28 0.23 0.18 0.69
0.23
Whole root + stem
0.32 0.23 0.72 1.27
0.42
Whole leaf
0.45 0.54 0.32 1.31
0.44
Cauliflower
Macerated root + stem
0.61 0.53 0.56 1.7
0.57
Macerated leaf
0.18 0.18 0.28 0.64
0.21
Chopped root + stem
0.36 0.49 0.79 1.64
0.55
Chopped leaf
0.48 0.08 0.11 0.67
0.22
Whole root + stem
0.38 0.43 0.48 1.29
0.43
Whole leaf
0.32 0.34 0.23 0.89
0.30
Cabbage cv. Scorpio
Macerated root + stem
0.61 0.57 0.38 1.56
0.52
Macerated leaf
0.96 1.13 0.94 3.03
1.01
Chopped root + stem
0.9 0.78 0.53 2.21
0.74
Chopped leaf
0.08 0.08 0.26 0.42
0.14
Whole root + stem
0.2 0.82 0.65 1.67
0.56
Whole leaf
0.51 0.46 0.23 1.2
0.40
Cabbage cv. Rareball
Macerated root + stem
0.58 0.71 0.63 1.92
0.64
Macerated leaf
0.41 0.23 0.38 1.02
0.34
Chopped root + stem
1.07 1.2 0.82 3.09
1.03
Chopped leaf
1 0.69 1.09 2.78
0.93
Whole root + stem
1.06 0.93 0.95 2.94
0.98
Whole leaf
0.04 0.18 0.2 0.42
0.14
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
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40
Appendix Table 5. Continued...
REPLICATION
TREATMENT I
II
III TOTAL MEAN
Radish
Macerated root + stem
0.28 0.6 0.54 1.42 0.47
Macerated leaf
0.86 0.96 1.18 3
1.00
Chopped root + stem
0.7 0.76 0.6 2.06 0.69
Chopped leaf
0.87 1.09 1.08 3.04
1.01
Whole root + stem
0.98 0.73 0.87 2.58
0.86
Whole leaf
0.6 0.71 0.36 1.67
0.56
Mustard
Macerated root + stem
0.49 0.52 0.61 1.62
0.54
Macerated leaf
0.23 0.18 0.3 0.71 0.24
Chopped root + stem
0.41 0.34 0.76 1.51
0.50
Chopped leaf
1.02 0.89 0.97 2.88
0.96
Whole root + stem
0.97 0.84 1.06 2.87
0.96
Whole leaf
0.41 0.4 0 0.81 0.27
Pechay
Macerated root + stem
0.43 0.94 0.85 2.22
0.74
Macerated leaf
0.7 0.96 0.86 2.52
0.84
Chopped root + stem
0.64 0.28 0.18 1.1
0.37
Chopped leaf
0.63 0.53 0.45 1.61
0.54
Whole root + stem
0.79 0.54 0.71 2.04
0.68
Whole leaf
0.72 0.99 0.79 2.5
0.83
Radish + mustard
Macerated root + stem
0.32 0.36 0.18 0.86
0.29
Macerated leaf
0.61 0.51 0.89 2.01
0.67
Chopped root + stem
0.04 0.08 0.48 0.6
0.20
Chopped leaf
0.49 0.32 0.45 1.26
0.42
Whole root + stem
0.11 0.73 0.69 1.53
0.51
Whole leaf
0.57 0.51 0.46 1.54
0.51
Untreated
1.3 1.29 1.11 3.7
1.23
TOTAL
29.04 29.72 29.85 88.61
MEAN
0.54 0.55 0.55
0.55
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
41
ANOVA TABLE
SOURCE OF DF SS MS FC Tab F
VARIATION 0.05 0.01
Factor A
8
3.08
0.38
14.41**
2.03
2.69
Factor B
5
0.56
0.11
4.21**
2.3
3.2
A x B
40
7.27
0.18
6.81**
1.51
1.79
Error 108
2.89
0.03
TOTAL 161 13.83
CV = 29.88%
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
42
Appendix Table 6. Final population of Ralstonia solanacearum in the soil (log cfu/g soil
x 104)
REPLICATION
TREATMENT I
II
III TOTAL MEAN
Sunflower
Macerated root + stem
1.07 0.34 0.83 2.24
0.75
Macerated leaf
0.71 0.62 0.65 1.98
0.66
Chopped root + stem
1.09 1.08 1.1 3.27
1.09
Chopped leaf
0.26 0.23 0.34 0.83
0.28
Whole root + stem
0.08 0.23 0.18 0.49
0.16
Whole leaf
0.2 0.23 0.18 0.61
0.20
Broccoli
Macerated root + stem
0.41 0.28 0.34 1.03
0.34
Macerated leaf
0.3 0.34 0.34 0.98
0.33
Chopped root + stem
0.41 0.2 0 0.61
0.20
Chopped leaf
0.15 0 0 0.15
0.05
Whole root + stem
0.43 0.51 0.41 1.35
0.45
Whole leaf
0.57 0.2 0.41 1.18
0.39
Cauliflower
Macerated root + stem
0.66 0.51 0.49 1.66
0.55
Macerated leaf
0.32 0.41 0.34 1.07
0.36
Chopped root + stem
0.32 0.58 0.62 1.52
0.51
Chopped leaf
0.3 0.34 0.36 1
0.33
Whole root + stem
0.61 0.74 0.7 2.05
0.68
Whole leaf
0.18 0.08 0.3 0.56
0.19
Cabbage cv. Scorpio
Macerated root + stem
0.04 0.08 0.11 0.23
0.08
Macerated leaf
0.87 0.96 0.76 2.59
0.86
Chopped root + stem
0.23 0.3 0.36 0.89
0.30
Chopped leaf
0.3 0 0 0.3
0.10
Whole root + stem
0.08 0.08 0.04 0.2
0.07
Whole leaf
0.11 0.45 1.01 1.57
0.52
Cabbage cv. Rareball
Macerated root + stem
0.43 0.52 0.3 1.25
0.42
Macerated leaf
0.41 0.28 0.4 1.09
0.36
Chopped root + stem
0.96 0.46 0
1.42
0.47
Chopped leaf
0.28 0.26 0.23 0.77
0.26
Whole root + stem
0.83 1 0.81 2.64
0.88
Whole leaf
0.04 0.3 0.23 0.57
0.19
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
43
Appendix Table 6. Continued...
REPLICATION
TREATMENT I
II
III TOTAL MEAN
Radish
Macerated root + stem
0.74 0.26 0
1
0.33
Macerated leaf
0.36 0.45 0.26 1.07 0.36
Chopped root + stem
0.66 0.89 0.95 2.5
0.83
Chopped leaf
0.91 0.99 1.03 2.93 0.98
Whole root + stem
0.78 0.51 0.43 1.72 0.57
Whole leaf
0.85 0.49 0.61 1.95 0.65
Mustard
Macerated root + stem
0.79 0.71 0.66 2.16 0.72
Macerated leaf
0.08 0.26 0.23 0.57 0.19
Chopped root + stem
0.87 0.87 0.73 2.47 0.82
Chopped leaf
1.03 1 0.81
2.84 0.95
Whole root + stem
0.36 0.41 0.43 1.2
0.40
Whole leaf
0.71 0.61 1.15 2.47 0.82
Pechay
Macerated root + stem
0.99 0.95 0.49 2.43 0.81
Macerated leaf
1.15 1.37 1.1 3.62 1.21
Chopped root + stem
0.18 0.18 0.15 0.51 0.17
Chopped leaf
0.4 0.36 0.28 1.04 0.35
Whole root + stem
0.3 0.92 0.72 1.94 0.65
Whole leaf
0.83 0.91 0.98 2.72 0.91
Radish + mustard
Macerated root + stem
0.73 0.46 0.66 1.85 0.62
Macerated leaf
0.32 0.38 0.4 1.1
0.37
Chopped root + stem
0.58 0.51 0.53 1.62 0.54
Chopped leaf
0.2 0.08 0.23 0.51 0.17
Whole root + stem
0.7 0.8 0.54 2.04 0.68
Whole leaf
0.08 0.04 0.2 0.32 0.11
Untreated
1.43 1.3 1.21 3.94 1.31
TOTAL
27.25 26.02 25.41 78.68
MEAN
0.50 0.51 0.47
0.49
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
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44
ANOVA TABLE
SOURCE OF DF SS MS FC Tab F
VARIATION 0.05 0.01
Factor A
8
2.86
0.36
13.31**
2.03
2.69
Factor B
5
0.50
0.10
3.73**
2.3
3.2
A x B
40
10.02
0.25
9.32**
1.51
1.79
Error 108
2.90
0.03
TOTAL 161 16.29
CV = 33.75%
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
45
Appendix Table 7. Changes in the population of Ralstonia solanacearum as affected by the combinations of biofumigant and tissue
preparation (log cfu/g soil x 104).
TREATMENT ASSESSMENT
PERIOD
Initial Week1 Week2
Week3
Week4 Week5
Sunflower
Macerated root 0.41lmnopq 0.51klmno 1.81abcd 0.38ijklmnopqrs 0.67cdefghi
0.75cdefghij
and stem
Macerated leaf
0.50hijklmnop 1.24a 0.71bcdefghijklm 0.57efghijklmno 0.42hijklmnop 0.66cdefghijklm
Chopped root and
0.86bcde 0.93cdef 0.92abcdefghij 1.31a 0.59efghijkl 1.09ab
stem
Chopped leaf
0.66efghijkl 0.81fgh 0.86abcdefghijkl 0.67cdefghijk 0.8abcde 0.27pqrstuvw
Whole root and
0.44klmnop
0.41opqrs 0.56ghijklmnop
0.13rs 0.22nopq 0.16stuvw
stem
Whole leaf
0.72defghijk 0.63ijk 0.77abcdefghijklmn 0.57efghijklmno 0.47hijklmnop 0.20qrstuvw
Broccoli
Macerated root
0.22pq 0.3st 0.27nop 0.72cdefghi 0.30lmnopq 0.34mnopqrstuvw
and stem
Macerated leaf
0.63efghijklm 0.65efg 0.47hijklmnop 0.42hijklmnopqrs 0.22opq 0.32nopqrstuvw
Chopped root and
0.97bcd 0.48mnop 0.53ghjiklmnop 0.64defghijklm 0.32klmnopq 0.20qrstuvw
stem
Chopped leaf
0.40lmnopq 0.31rst 0.25nop 0.20pqrs 0.23nopq 0.5w
Whole root and
0.59efghijklm 0.82fgh 0.64efghijklmnop 0.28nopqrs 0.42hijklmnopq 0.45jklmnopqrs
stem
Whole leaf
0.85bcde 0.34pqrst 0.42ijklmnop 0.19pqrs 0.43hijklmnopq 0.39lmnopqrstuv
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
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46
Appendix Table 7. Continued...
Cauliflower
Macerated root 0.51ghijklmnop 0.55klmn 0.34lmnop 0.32lmnopqrs 0.56efghijklm 0.55ghijklmnop
and stem
Macerated leaf
1.01abc 0.61jklm 0.72bcdefghijklm 0.55efghijklmn 0.21opq 0.35lmnopqrtuvw
Chopped root and
0.82bcdef 0.34qrst 0.18op 0.63bcdef 0.54efghijklmno 0.51ijklmnopqr
stem
Chopped leaf
0.38lmnopq 0.46nopq 0.48hijklmnop 0.82bcdefg 0.22nopq 0.33mnopqrstuvw
Whole root and
0.30nopq 0.70hij 1.21ab 0.79pqrs 0.43hijklmnopq 0.68cdefghijkl
stem
Whole leaf
1.07ab 0.0.77gh 1.09abcedf 0.18pqrs 0.29lmnop 0.18rstuvw
Cabbage cv.
Scorpio
Macerated root 0.48jklmnop 0.8efh 0.89abcdefghjk 0.67cdefghijk 0.52fghijklmnop 0.77uvw
and stem
Macerated leaf
0.76cdefghjk 1.03bc 1.21abc 0.56efghijklmno 1.01a 0.86bcdefg
Chopped root and
0.80bcdefg 0.90def 0.59fghjiklmnop 0.49fghijklmnopq 0.73abcdefgh 0.30opqrstuvw
stem
Chopped leaf
0.61efghijklm 0.63ijk 0.52ghijklmnop 1.07ab 0.14q 0.10tuvw
Whole root and
0.34mnoopq 0.27t 0.26nop 0.13s 0.56efghjiklm 0.07vw
stem
Whole leaf
0.53ghijklmn 0.24t 1.2abc 0.77bcdefg 0.40ijklmnopq 0.52hijklmnopq
Cabbage cv.
Rareball
Macerated root 0.54fghijklm 1.12b 1.25a 0.89bcde 0.64defghijk 0.41klmnopqrst
and stem
Macerated leaf
0.78cdefgh 1.03bc 0.72bcdefghijklmn 0.35jklmnopqrs 0.34jklmnopq 0.36lmnopqrstuvw
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
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47
Appendix Table 7. Continued...
Chopped root and
046klmnopq 0.49lmno 0.97abcdefgh 0.47ghijklmnopqr 1.03a 0.47jklmnopqrs
stem
Chopped leaf
0.24opq 0.26t 0.98abcdefgh 0.47ghijklmnopqr 0.92abcd 0.25opqrstuvw
Whole root and
0.28q 0.24t
0.46hijklmnop 0.88bcde 0.98abc 0.88bcdef
stem
Whole leaf
0.2lmnopq 0.28st 1.23ab 0.95bcd 0.14q 0.19rstuvw
Radish
Macerated root 0.38ijklmnopq 0.23t 0.76abcdefghijklmn 0.95bcd 0.47hijklmnop 0.33mnopqrstuvw
and stem
Macerated leaf
0.48fghijklmn 0.41nopqrs 0.68defghjijklmno 0.20pqrs 1.00ab 0.35lmnopqrstuvw
Chopped root and
0.54abc 0.44nopq 0.88abcdefghijk 0.64defghijklm 0.68bcdefghi 0.83bcdefg
stem
Chopped leaf
1.05klmnopq 1.04bc 1.14abcde 0.52fghijklmnop 1.01a 0.97abc
Whole root and
0.47lmnopq 0.45nopq 0.28mnop 0.74cdefgh 0.86abcde 0.57fghijklmn
stem
Whole leaf
0.43lmnopq 0.52klmno 0.41jklmnop 0.33klmnopqrs 0.55efghijklm 0.65defghijklmn
Mustard
Macerated root
1.25a 1.29a 0.64efghijklmnop 0.74cdefgh 0.54efghijklmno 0.72cdefghijk
and stem
Macerated leaf
0.87bcde 0.33qrst 0.97abcdefgh 0.17qrs 0.24mnopq 0.19rstuvw
Chopped root and
1.03abc 0.85efg 1.03abcdefg 0.83bcdef 0.50hijklmnop 0.82bcdefghi
stem
Chopped leaf
0.59efghijklm 0.75ghi 0.37jlmnop 0.42hijklmnopqrs 0.96abcd 0.94abcd
Whole root and
1.02abc 1.01bcd 0.68cdefghijklmno 0.54efghijklmno 0.96abcd 0.40klmnopqrstu
stem
Whole leaf
0.85bcde 0.52klmno 0.40jklmnop 0.99bc 0.27lmnopq 0.82bcdefghi
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
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48
Appendix Table 7. Continued...
Pechay
Macerated root 0.61efghijklm 0.95cde 0.81abcdefghijklm 0.73cdefghi 0.74abcdefgh 0.81bcdefghi
and stem
Macerated leaf
0.46klmnopq 0.43nopqr 1.20abcd 0.66cdefghijkl 0.84abcdef 1.21a
Chopped root and
0.34mnopq 0.27t 0.34lmnop 0.64defghijklm 0.37ijklmnopq 0.17stuvw
stem
Chopped leaf
0.47ghijklmno 0.48mnop 0.30mnop 0.56efghijklmno 0.54efghijklmno 0.34mnopqrstuvw
Whole root and
0.53cdefghi 0.52klmnop 0.27nop 0.65cdefghijkl 0.68bcdefghi 0.64defghijklm
stem
Whole leaf
0.77cdefghi 0.70hij 0.58fghijklmnop 0.69cdefghij 0.83abcdefg 0.90bcde
Radish +
mustard
Macerated root 0.44klmnopq 0.29st 0.39jklmnop 0.24opqrs 0.29lmnopq 0.61efghijklmno
and stem
Macerated leaf
0.59efghijklm 0.41opqrs 0.13p 0.78bcdefg 0.67cdefghij 0.36lmnopqrstuvw
Chopped root and
0.97bcd 1.05bc 0.31mnop 0.30mnopqrs 0.20pq 0.54ghijklmnop
stem
Chopped leaf
0.78cdefgh 0.63ijk 0.75abcdefghijklmn 0.59efghijklmn 0.42hijklmnopq 0.17stuvw
Whole root and
0.62efghijklm 0.61jklm 0.77abcdefghijklmn 0.62defghijklm 0.51ghijklmnop 0.68cdefghijkl
stem
Whole leaf
0.65efghjikl 0.61jkl 0.94abcdefghi 0.67cdefghijkl 0.51fghijklmnop 0.10tuvw
Untreated 0.95a 0.92a 0.93a 1.06a 1.23a 1.31a
Evaluating the Biofumigation Potentials of Various Brassica Species for the Control of Ralstonia
solanacearum (E.F. Smith) Yabuuchi et al. Affecting Potatoes / Floresca T. Agustin. 2007
Document Outline
- Evaluating the Biofumigation Potentials
of Various Brassica Species for the Control of Ralstonia solanacearum (E.F. Smith)
Yabuuchi et al. Affecting Potatoes
- BIBLIOGRAPHY
- ABSTRACT
- TABLE OF CONTENTS
- INTRODUCTION
- REVIEW OF LITERATURE
- MATERIALS AND METHODS
- Sources of Test Materials
- Preparation of Brassica Tissues
- Evaluation of the Bactericidal Potential of Brassica Tissues
- Data Gathered
- RESULTS AND DISCUSSIONS
- Effect of Biofumigant
- Effect of Tissue Preparation
- Interaction Effect
- SUMMARY, CONCLUSIONS AND RECOMMENDATIONS
- LITERATURE CITED
- APPENDICES