BIBLIOGRAPHY YADYADOC, ESTRELLA T. APRIL ...
BIBLIOGRAPHY
YADYADOC, ESTRELLA T. APRIL 2011. Effect of Entomopathogenic Nematodes
(EPNs) On Root-knot Nematodes, (Meloidogyne incognita) in Carrot. Benguet State University,
La Trinidad Benguet.
Adviser: Luciana M. Villanueva, PhD.
ABSTRACT
The study was conducted at BIOCON laboratory and greenhouse of Benguet State
University, La Trinidad Benguet from September 2010 to Mach 2011. Three levels of wax larva
infected with approximately 100, 300 and 100 entomopathogenec nematodes (EPNs) were
evaluated to determine their effect on root knot nematode, Melodogyne incognita and on the
growth and yield of carrot, cv. Tokita. Untreated plants and those treated with standard
nematcide, Carbofuran (D’grand) were provided to serve as controls. The treatments were
replicated five times and arranged randomly in the greenhouse using Completely Radomized
Design (CRD).
Application of EPNs did not significantly affect the number of root knot nematodes in the
roots. However, although not significantly different, the number of galls on the secondary root
was generally higher in the control plants than those applied with EPNs.
Likewise, the growth parameters of carrots such as fresh top weight, fresh root weight,
oven dry top weight, marketable and non-marketable root weight, were not significantly affected
by EPN application.
TABLE OF CONTENTS
Page
Bibliography. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
i
Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
i
Table of Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ii
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
REVIEW OF LITERATURE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3
The Crop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3
The Importance of the Crop . . . . . . . . . . . . . . . . . . . . . . . . . . .
3
The Causal Pathogen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3
Symptoms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4
Entomopathogenic Nematodes (EPNs) . . . . . . . . . . . . . . . . . . .
4
Beneficial Effects of EPNs . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5
Biology of Nematode/Bacterium Complex . . . . . . . . . . . . . . .
6
MATERIALS AND METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8
RESULTS AND DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12
Meteorological Condition . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12
Number of Nematodes in Roots . . . . . . . . . . . . . . . . . . . . . . .
12
Number of Galls on Secondary Root . . . . . . . . . . . . . . . . . . . .
13
Fresh Top Weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14
Fresh Root Weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14
Yield . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15
SUMMARY, CONCLUSIONS AND RECOMMENDATIONS . . . .
16
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16
Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17
Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17
LITERATURE CITED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
18
APPENDICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20
1
INTRODUCTION
Carrot is one of the principal crops usually raised in the highlands and thus have
gained great importance. Carrot is a good source of calcium and carotene. It is also a
good source of protein, thiamine and ascorbic acid. It is commonly used as spice and can
be eaten raw (Abuan, 2003).
In Benguet particularly, it is usually produced from October to May, or even the
whole year round depending on the topography of the land, the environment and the
availability of the factors of production.
In the Philippines especially in Benguet, root-knot nematode has already been
found affecting the production of carrots. Depending on the variety and nematode
population densities, the nematode could significantly affect the quality of the tap root
making them commercially undesirable. According to Townshend (1962), many carrots
are discarded in the fresh market and processing industry because of the tap root galling
due to M. hapla infection. The more number of nematodes present/penetrating the roots
the more damage is done on plants. But in the case of susceptible variety, even at low
inoculum level, the quality and quantity of carrots could be significantly reduced.
Farmers however, often encounter problems with carrot plants, despite proper
cultural practices and control of insects, weeds and other diseases. The possibility that
their plants have been attacked by nematodes is great. These tiny organisms cause
primary infection on plants by creating avenues or entry points for other pathogens.
Root knot nematodes, Meloidogyne incognita are obligate parasite capable of
feeding inside the roots. The first of four molts occur in the egg and the nematodes hatch
as second stage juveniles (J2s) which are the infective form. Typically, root knot
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
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nematode development begins inside the egg. Adult female deposits eggs into a
protective gelatinous matrix, near or just outside the root surface. A single female lays
about 500 to 1500 eggs during her life, which last about two to three months. After the
completion of embryogenesis, the first stage juvenile remains inside the egg until it molts
into second stage – juvenile. After the second stage juvenile hatches from the egg, it
moves freely in the soil in search of suitable host plant (Williamson and Gleason, 2003).
Crop production is the main source of income for most farmers in Benguet.
Control of the damage caused by root knot nematodes in agricultural settings often
requires the use of toxic pesticides. The use of entomopathogenic nematodes (EPNs) as
an alternative to pesticides will be of great help to farmers to improve their income and to
the country in general to increase food supply for the rapidly increasing population.
Reduction of pesticide use will be contributory to ecosystem conservation and protection
and ultimately to sustainable agriculture.
The study aims to evaluate the effect of different levels of EPNs on root knot
nematode, Meloidogyne incognita and on the growth and yield of carrot.
The study was conducted at the BIOCON laboratory and greenhouse of Benguet
State University, La Trinidad, Benguet from September 2010 to March 2011.
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
3
REVIEW OF LITERATURE
The Crop
Carrot (Daucuscarota L.) a biennial plant grown for its edible fleshy root is
usually orange in color, aromatic and sweet. A member of the carrot family
(Umbelloferae), carrot is believed to have originated from the Middle East. It is now
found worldwide, either as a cultivated plant or a weedy wild plant with long, dry roots.
Carrot thrives best on a deep loose loamy soil. The long smooth, slender carrot
desired for fresh marketing can be successfully grown only on deep well drained, high
soils. Experiments in Virginia and New York indicated maximum yields at around pH 6.5
and extremely low yields at pH 5.2 or below. Carrot requires an abundant and well
distributed water supply (Abuan, 2003).
Importance of the Crop
Carrot is rich in carotene, a precursor of Vitamin A, and contains appreciable
quantities of thiamine and riboflavin. Carrot is now gaining in importance because of its
high nutritive value, as stated by quantities of thiamine and riboflavin. It is also used in
many food preparations. It can be a principal ingredient of a dish – like carrot salad. It
gives attractive color and appearance to pickles. It is excellent for garnishing and is very
rich in vitamins.
The Causal Pathogen
Root knot nematodes are the most important plant parasitic nematodes in the
Philippines. It represents a relatively small, but economically important group of obligate
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
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plant pathogens (Agrios, 1997). It is the most common and widely distributed all over the
country attacking several vegetable crops, field crops, fruit crops and ornamentals.
Meloidogyne spp. is considered to be sedentary endoparasites. They invade the
roots and the development of the vermiform second stage juveniles (J2) depends upon the
modification of the phenotype and function of specific root cells to form specialized cells
that become the permanent source of nutrients for the parasites.
Symptoms
Damage caused by root-knot nematode is best determined by examining the roots
for the presence of galls. Nematode galls should not be confused with the root nodules of
leguminous plants. Nematode galls are characterized by swelling of the roots whereas
root nodules are merely attached to the roots.
Above ground symptoms of plants attacked by root – knot nematodes are stunting
and yellowing of leaves. In some vegetables, the plants may also show wilting during
warmer part of the day as if the plants lack water and eventually die. Plants with fleshy
roots are likely to be more severely damaged by root – knot nematodes than plants with
grass – type roots.
In carrots, symptoms of Meloidogyne spp. infection include galling, large
proliferation of secondary roots and tap root malformation such as severe forking and
stunting (Vrain, 1982 as cited by Belair, 1992).
Entomopathogenic Nematodes (EPNs)
Entomopathogenic nematodes (EPNs) of the families Steinernematidae and
Heterorhabditidae are obligate parasites of a wide range of insects (Fallion et al., 2002).
The infective stage, known as the infective juvenile (IJ), carries a symbiotic bacterium
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
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that is released following infection of the insect host. Steinernematids are associated with
Xenorhadus spp., and Heterorarhabditids are associated Photorhabdus spp. Once
infection has occurred, the bacteria release anti-microbial agents that help prevent
colonization of the insect cadaver by contaminating fungi and bacteria, and act as a food
source for developing EPNs (Kaya and Gaugler, 1993). The bacteria also produce
stillbene and indole metabolites that are nematicidal to a range of nematode species,
including some plant parasites.
Beneficial Effects of EPNs
Entomopathogenic nematodes have been used successfully to control a number of
compost and soil insects (Gouge and Hague, 1995). These same nematodes have shown
some potential as antagonists to plant parasitic nematodes (PPNs). Application of EPNs
to soil reduced a number of important PPN species including Meloidogyne spp.,
Belonolaimus spp., Tylenchorhyncus spp., and Criconematidae (Grewal et al., 1997).
EPNs tested in laboratory (Bird and Bird, 1986) and greenhouse studies and applied to
tomato plants inoculated with Meloidogyne spp., reduced nematode penetration and egg
production. Perry et.al. (1998) reported a reduction of Globoderarostochiensis
penetration in potato tubers treated with S. carpocapsae in greenhouse and outdoor trials.
A number of interactive effects may be involved in suppression of PPNs and
EPNs. Bird and Bird (1986) proposed the spatial competition at the mutually attractive
root tip may affect root - knot nematode penetration. Ishibashi and Kondo (1986)
suggested increased number of predators from the application of additional nematode
biomass.
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
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Biology of Nematode/Bacterium Complex
Steinermatids and Heterorhabditids are obligate pathogens in nature. Only the
non-feeding third stage infective juvenile (IJ) or dauer juvenile is capable of surviving
outside the insect host. The IJ carries cells of its bacterial symbiont in its intestinal tract.
After locating suitable host, the IJ invades it through natural openings (mouth, spiracles,
and anus) or thin areas of the host’s cuticle and penetrate into the host hemocoel. The IJ
releases its symbiont, and the bacterium and nematode cooperate to overcome the host’s
immune response (Chen et al., 2004).
The mutualistic bacterium propagates and produces substances that kill the host
and protect the cadaver from colonization by other microorganisms. The nematode
initiates its development, feeding on bacterial cells and host tissues that have been
metabolized by the bacterium and has 1-3 generations, depending on host size. As the
food resources in the host cadaver in search of a new host (Chen et al., 2004).
A major difference between Steinermatids and Heterorhabditids is that the species
in the former group are amphimictic, whilst species in the latter group are hermaphrodites
in the first generation but amphimictic in the following generations. Therefore,
Steirnermatids require at least two IJs, a male and a female, to invade the host to produce
progeny, and Heterorhabditids need only one IJ to penetrate into the host as the resulting
hermaphroditic adult is self-fertile.
Each nematode species is specifically associated with one bacterial symbiotic
species; however, the symbiotic species maybe associated with more than one nematode
species. This specificity operates at 2 levels. First, the best nematode reproduction occurs
on their natural symbiont even though, in some cases, the nematode develops on other
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
7
bacterial species. Second, the natural bacterial symbionts are retained better than other
bacterial species. The nematode is dependent upon the mutualistic bacterium for quickly
killing its insect host; creating a suitable environment for its development, producing
antibiotics that suppress competing microorganisms and transforming the host tissues into
a food source. The bacterium requires the nematode for protection from external
environment, penetration into the host’s hemocoel and inhibition of the host’s
antibacterial proteins (Chen et al., 2004).
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
8
MATERIALS AND METHODS
The study was conducted at the BIOCON Laboratory and greenhouse of Benguet
State University, La Trinidad, Benguet from September 2010 to March 2011.
Source of Inoculum (M. incognita)
The root-knot nematode Meloidogyne incognita was used in the experiment.
These inocula have been maintained in a susceptible variety of garden pea grown in pots
under greenhouse condition in order to have a ready source of inoculum.
Plant Material
Carrot seeds cv. Tokita was directly sown in 7x7x14 cm diameter plastic pots
containing 3 kg heat sterilized soil. Thinning was done six weeks from the time of seed
sowing, maintaining 1 plant per pot. The plants were inoculated a week after thinning.
Preparation of Inocula
Eggs of root-knot nematode were collected from egg masses by dissolution of the
gelatinous matrix. The infected roots were washed thoroughly and cut into small sizes.
The cut roots were shaken for four minutes in stoppered flask containing 5.25% liquid
bleached (Clorox) diluted with four volumes of water making 1% NaOCl solution. The
liquid was poured over rested sieves and collected eggs were washed thoroughly with tap
water to remove the bleach. Suspensions were poured over the blue sieve lined with
tissue paper. Tap water was added reaching the bottom of the sieve. This allowed the
eggs of the root knot nematode to hatch. After 48 hours, J2s were collected in a beaker.
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
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Source of Entomopathogenic Nematodes
Steinernema sp. All strain IJs were produced in the last instar wax moth Achroia
grisella (Figure 1). EPN infected A. grisella cadavers (hereafter termed as cadavers) were
obtained by infecting each last instar A. grisella larva with approximately 100
Steinernema sp. IJs.
Lesser wax moth infected with EPNs were focused under dissecting microscope
(Figure 2).
Figure 1. Lesser wax moth (Achroia grisella) used for the mass propagation of EPNs
Figure 2. Close up view of EPNs inside Achroia grisella
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
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Nematode Inoculation
After seedling emergence and when the plants were already well established, all
treatments were inoculated with 1000 second stage juveniles per plant. Four holes were
made in the soil near the plant zone. Using a pipette, the nematode suspension was
distributed in each hole and covered again with soil.
Entomopathogenic nematodes were applied immediately after nematode
inoculation.
The treatments were:
T1 – 0 wax moth cadaver
T2 – 1 wax moth cadaver (approximately100 EPNs)
T3 – 3 wax moth cadavers (approximately 300 EPNs)
T4 – 5 wax moth cadavers (approximately 500 EPNs)
T5 – D’grand- (.4g)
The different treatments were replicated 6 times. The plants were arranged in the
greenhouse using CRD (Figure 3).
Figure 3. Experimental lay-out
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
11
All the cultural management practices for commercial carrot production such as
watering, fertilization control of insect pest and diseases except nematodes were
employed to all treatments to insure the good growth and yield of the plants.
Data Gathered
1. Number of nematodes in soil (200cc). About 200cc of soil was processed
using the modified- tray method.
2. Number of nematodes in roots (2g). Two grams of roots was stained by using
acid-fuchsin and the number of nematodes was counted using a dissecting microscope.
3. Number of galls. The individual galls in the whole root system was counted.
4. Fresh top weight. The vegetative part of the plants was cut at about 6cm from
the soil then weighed.
5. Fresh root weight (g). The roots were washed thoroughly with running water
and weighed separately.
6. Oven dry top weight (g).The upper part of the plant was oven dried at 720 C
for 48 hours.
7. Yield (kg).The marketable and non-marketable roots were weighed separately.
Data Analysis
The data were analyzed statistically using analysis of variance (ANOVA) and
treatment means were separated using Duncan’s Multiple Range Test (DMRT).
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
12
RESULTS AND DISCUSSION
Meteorological Condition
Table 1 shows the average temperature and relative humidity during the conduct
of the study. Apparently, the above conditions were not favorable for the development
and reproduction of root- knot nematodes. According to Hine (1965) the duration of the
life cycle depends on the temperature; when it is maintained at a low level the nematode
numbers increase slowly. All eggs do not hatch simultaneously; some of them hatch only
several months after egg laying resisting cold and dryness. Luc et al. (2004) reported that
one cycle was completed in 19 days at 300C versus 43 days at 21.80C.
Number of Nematodes in Roots
The number of nematodes observed from the 2g root of the different treatments
did not differ significantly. However, higher number of nematodes was recorded from the
roots obtained from the control plants than those applied with different levels of EPN
(Table 2). Surprisingly, no nematode was recovered from the soil which indicates that
perhaps some of the nematodes died and were not able to infect the plants.
Table 1. Average temperature and relative humidity during the conduct of the study
TEMPERATURE
RH
MONTHS
MAXIMUM
OPTIMUM
MINIMUM
(%)
November
24.80
15.20
20.00
86.00
December
25.10
13.60
19.35
92.00
January
24.30
13.00
18.65
85.30
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
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Number of Galls on Secondary Roots
Table 2 shows the effect of the different treatments on the number of galls in the
secondary roots of carrot. Although not significantly different, the inoculated plants
without EPNs had the highest number of galls compared to those plants treated with
EPNs. Apparently, application of three infected cadavers wax moth (approximately 300
EPNs) was better than those applied with the highest number of wax moth cadavers
(approximately 500 EPNs). On the other hand, the standard nematicide, Carbofuran, (D’
grand) showed the lowest number of galls. Perez and Lewis (2004) reported that M.
hapla inside the roots and egg recovery from seedlings treated with EPNs was
significantly less than those in the control. The low rate of Steirnernema glaseri
suppressed M. incognita penetration into tomato roots and the high rate of S. glaseri
reduced egg production.
On the other hand, since the nematodes were not able to reproduce due to
unfavorable conditions for growth and development, no egg mass was observed in the
roots.
Table 2. Effect of entomopathogenic nematode (EPNs) on the number of galls and
nematodes on the roots
TREATMENTS
NUMBER OF GALLS NUMBER OF NEMATODES IN
ROOTS
0 wax moth cadavers
8.00a
5.17a
1 wax moth cadavers
3.17a
1.67a
3 wax moth cadavers
2.83a
1.67a
5 wax moth cadavers
3.00a
1.33a
D’grand (0.4 g)
0.50a
0.50a
Means followed by similar letters are not significantly different at 5% level using DMRT.
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
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Fresh Top Weight
Table 3 shows the effect of entomopathogenic nematodes (EPNs) on the fresh top
weight of carrot inoculated with root knot nematode. Evidently, no significant differences
were noted among the treatments. Nevertheless, application of three wax moth cadavers
resulted in the highest fresh top weight (31.83 g) while the lowest (2.33 g) was obtained
from the plants applied with the standard nematicide, D’grand. The same trend was
observed in the oven dry top weight.
Fresh Root Weight
Similar to the fresh top weight, application of EPNs did not significantly affect
the fresh root weight of inoculated carrots (Table 3). Numerically however, plants
inoculated with root-knot nematode and applied with one (1) wax moth cadaver gave the
highest fresh root weight (89.83 g). Unexpectedly, the lowest fresh root weight was
recorded from inoculated carrots applied with five (5) wax moth cadavers (61.17 g).
Table 3. Effect of entomopathogenic nematodes (EPNs) on the growth parameters of
carrot (g)
TREATMENTS
FRESH
FRESH
OVEN DRY MARKETABLE
NON
TOP
ROOT
TOP
ROOT
MARKETABLE
WEIGHT WEIGHT
WEIGHT
(g)
ROOT
0 wax moth cadavers
30.00a
80.83a
5.85a
78.17a
1.17a
1 wax moth cadavers
28.67a
89.83a
4.997a
61.17a
28.67a
3 wax moth cadavers
31.83a
87.67a
6.25a
59.00a
28.67a
5 wax moth cadavers
24.5a
61.17a
4.28a
32.82a
28.33a
D’grand (.4 g)
22.33a
72.67a
3.96a
59.00a
13.67a
Means followed by similar letters are not significantly different at 5% level using DMRT.
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
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Yield
The effect of EPN on the marketable yield was not significant (Table 3).
Unexpectedly; higher yield was obtained in the untreated compared to the treated plants.
However, lower yield on the treated ones was not attributed to nematode infection but
rather to improper management of the crop that could have affected the growth. Due to
very dense planting, thinning of the plants may have disturbed the main root resulting to
forking of the tap root.
The effect of entomopathogenic nematodes (EPNs) on the non-marketable yield
was also not significant (Table 3). Symptoms on non-marketable root include rotting,
forking and cracking of the tap root.
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
16
SUMMARY, CONCLUSIONS AND RECOMMENDATIONS
Summary
A greenhouse experiment was conducted at the BIOCON laboratory and
greenhouse of Benguet State University, La Trinidad, Benguet from September 2010 to
Mach 2011to determine the effect of entomopathogenic nematodes (EPNs) on root- knot
nematode, (Meloidogyne incognita) and on growth and yield of carrot.
Application of 1, 3 and 5 wax moth cadavers infected with EPNs in carrot cv.
Tokita inoculated with 1000 juveniles of Meloidogyne incognita did not significantly
affect the number of nematodes in the roots. The absence of nematodes in the soil and the
presence of very few nematodes in the roots indicate that some of the nematodes died and
were not able to infect the plants. This was attributed to unfavorable weather condition
that could have affected the growth and development of root-knot nematodes.
Although not significantly different, the number of galls in the secondary root was
generally higher in the untreated control than those applied with entomopathogenic
nematodes (EPNs). Because of very low temperature, the nematode development and
reproduction was delayed, thus no egg masses were produced.
Likewise no significant differences were also noted on the growth parameters of
carrot: fresh top weight, fresh root weight, oven dry top weight, marketable and non-
marketable yield.
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
17
Conclusions
1. Results of the experiment shows that application of different levels of wax
moth cadavers infected with EPNs did not significantly affect the number of root knot
nematodes that penetrated the roots including the number of galls. Since the temperature
was very low, the growth and development of both the root knot nematode and EPNs
were delayed. Thus, no egg mass was also detected.
2. Because of the above reason, the growth and yield parameters of carrot were
also not significantly affected by EPN application.
Recommendations
Since the experiment was greatly affected by unfavorable temperature additional
studies are necessary to fully evaluate the efficacy of entomopathogenic nematodes
against root-knot nematode in carrot. It is recommended that studies should be done
during summer when the temperature is conducive for the growth and development of
both RKN and EPNs in order to have more conclusive results.
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
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LITERATURE CITED
ABUAN, M. M. 2003. Response of two carrot (Daucuscarota L.) cultivars to varying
levels of root-knot nematode. BS Thesis. (Benguet State University. La Trinidad,
Benguet. P. 12.
AGRIOS, G. N. 1997. Plant Pathology. 4th Edition. San Diego, California. Pp. 565-567.
BIRD, A. F., and J. BIRD. 1986. Observations on the use of entomopathogenic
nematodes as means of biocontrol of root-knot nematodes. International Journal
of Parasitology 16:511-516.
BELAIR, G. 1992. Effect of Cropping Sequences on Population Densities of
Meloidogyne hapla and Carrot Yield in Organic Soil. Journal of Nematology. 24
(3): 450-456.
CHEN, Z., S. CHEN and D.W. DICKSON. 2004. Nematology-Advances and
Perspective, CABI Publishing. Pp.1098-1099.
FALLION, D. J. KAYA, R. GAUGLER and B. S. SIPES. 2002. Effect of
Entomopathogenic Nematodes on Meloidogyne incognita on Tomato and
Soybean. Journal of Nematology 34(3):239.
GREWAL, P. S., W. R. MARTIN, R. W. MILLER and E. E. LEWIS. 1997. Suppression
of plant-parasitic nematode populations in turf grassby entomopathogenic
nematodes. Nematology1:735-743.
GOUGE, D. H. and N. HAGUE. 1995. Glasshouse control of fungus gnats, Bradysia
pauperaon fuchsias by Steinermafeltiae. Fundamental and Applied Nematology
18:77-80.
HINE, R. B., O. V. HOLTZMAN, and R. D. RAABE. 1965. Disease of Carrot in Hawaii.
Hawaii Agric. Exp. Stn. Bull.136, Univ. of Hawaii. P. 26.
ISHIBASHI, N., and E. KONDO. 1986. Steinernemafeltiae (DD-136) and S. glaseri:
Persistence in soil and bark compost and their influence on native nematodes.
Journal of Nematology 18:310-316.
KAYA, H. K., and R. GAUGLER. 1993. Entomopathogenic nematodes. Annual Review
of entomology 38:181-206.
LUC, M., RICHARD.S., J. BRIDGE. 2005. Plant parasitic Nematodes in Subtropical and
Tropical Agriculture.CABI Publishing P. 331.
PEREZ, E. E., and E. E. LEWIS. 2004. Entomology Department,Virginia Tech,
Blacksburg, VA 24061,USA Biological Control. Vol 30. Pp .336-341
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
19
PERRY. R. N., HOMONICK. W. M., BEANE. J., BRISCOSE. B., 1998. Effect of the
entomopathogenic nematodes, Steinermafeltiae and S. carpocapsae, on the potato
cyst nematode, Globoderarostochiensis, in pot trials. Bocontrol Science and
Technology 8:175-180.
TOWNSHEND, J. L. AND T. R. DAVIDSON. 1962. Some Weed Hosts of the Northern
Root- knot Nematode Meloidogyne hapla (Chiwood,1948) Ontario, Canada.
Journal of Botany. 17:154-66.
WILLIAMSON, V. M. and C. A. GLEASON. 2003. Plant-nematode Interactions.
CurrentOpinion in Plant Biology. 6:327-333.
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
20
APPENDICES
Appendix Table 1. Effect of EPNs, on the number of nematodes in roots (2g) of carrots
cv. Tokita inoculated with root knot nematode, M. incognita
TREATMENT
REPLICATION
No. of wax moth cadaver
I
II
III
TOTAL
MEAN
T1-0
14.5
1.00
0.00
15.50
5.17
T2-1
0.50
1.00
3.50
5.00
1.67
T3-3
2.00
1.00
2.00
5.00
1.67
T4- 5
0.50
1.50
2.00
4.00
1.33
T5-D’grand
1.00
0.00
0.50
1.50
0.50
ANALYSIS OF VARIANCE
SOURCE
DF
SS
MS
F-VALUE
TABULAR
0.05
0.01
Replication
2
21.333
10.67
0.7232
3.84
7.01
Treatment
4
38.767
9.692
0.6602ns
Error
8
117.433
14.679
Total
14
177.433
ns – Not significant Coefficient of variation = 185.26%
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
21
Appendix Table 2. Effect of EPNs, on the number of nematodes in roots (2g) of carrots
cv. Tokita inoculated with root knot nematode, M. incognita
TREATMENTS
REPLICATION
No. of wax moth cadaver
I
II
III
TOTAL
MEAN
T1-0
3.87
1.22
0.71
5.80
1.93
T2-1
1.00
1.22
2.00
4.22
1.41
T3-3
1.58
1.22
1.58
4.38
1.46
T4- 5
1.00
1.41
1.58
3.99
3.00
T5-D’grand
1.22
0.71
1.00
2.93
0.997
ANALYSIS OF VARIANCE
SOURCE
DF
SS
MS
F-VALUE
TABULAR
0.05
0.01
Replication
2
1.41
0.43
0.58
3.84
7.01
Treatment
4
0.85
0.35
0.4838ns
Error
8
5.85
0.73
Total
14
8.113
ns – Not significant Coefficient of variation = 60.17%
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
22
Appendix Table 3. Effect of EPNs, on the number of galls of carrots cv. Tokita
inoculated with root knot nematode, M. incognita
TREATMENTS
REPLICATION
No. of wax moth cadaver
I
II
II
TOTAL
MEAN
T1-0
4.58
2.00
0.71
7.29
2.43
T2-1
1.22
1.73
2.55
5.50
1.83
T3-3
2.12
1.58
1.73
5.43
1.81
T4- 5
1.22
2.24
2.12
5.36
1.79
T5-D’grand
0.71
1.00
2.93
0.98
ANALYSIS OF VARIANCE
SOURCE
DF
SS
MS
F-VALUE
TABULAR
0.05
0.01
Replication
2
0.512
0.256
0.218
3.84
7.01
Treatment
4
3.212
0.803
0.685ns
Error
8
9.376
1.172
Total
14
13.090
ns – Not significant Coefficient of variation = 61.26%
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
23
Appendix Table 4. Effect of EPNs, on the fresh top weight of carrots cv. Tokita
inoculated with root knot nematode, M. incognita
TREATMENTS
REPLICATION
No. of wax moth cadaver
I
II
III
TOTAL
MEAN
T1-0
25.50
31.50
33.00
90.00
30.00
T2-1
28.00
38.00
20.00
86.00
28.67
T3-3
27.00
40.50
28.00
95.50
31.83
T4- 5
26.50
20.00
27.00
73.50
24.50
T5-D’grand
21.50
23.50
22.00
67.00
22.33
ANALYSIS OF VARIANCE
SOURCE
DF
SS
MS
F- VALUE
TABULAR
0.05
0.01
Replication
2
78.633
39.312
1.2034
3.84
7.01
Treatment
4
186.233
46.558
1.4251ns
Error
8
261.367
32.671
Total
14
526.233
ns – Not significant Coefficient of variation = 21.25%
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
24
Appendix Table 5. Effect of EPNs, on the fresh root weight of carrots cv. Tokita
inoculated with root knot nematode, M. incognita
TREATMENTS
REPLICATION
No. of wax moth cadaver
I
II
III
TOTAL
MEAN
T1-0
86.50
68.50
87.50
242.50
80.83
T2-1
105.00
115.00
49.50
269.50
98.86
T3-3
72.50
90.00
71.00
263.00
87.67
T4- 5
72.50
57.00
54.00
183.50
61.17
T5-D’grand
79.00
63.50
75.50
218.00
72.67
ANALYSIS OF VARIANCE
SOURCE
DF
SS
MS
F- VALUE
TABULAR
0.05
0.01
Replication
2
1156.633
578.317
1.94
3.84
7.01
Treatment
4
1657.100
414.275
1.39ns
Error
8
2380.200
297.525
Total
14
5193.933
ns – Not significant Coefficient of variation = 21.99%
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
25
Appendix Table 6. Effect of EPNs, on the oven dry top weight of carrots cv. Tokita
inoculated with root knot nematode, M. incognita
TREATMENTS
REPLICATION
No. of wax moth cadaver
I
II
III
TOTAL
MEAN
T1-0
9.20
2.58
5.78
17.56
5.76
T2-1
5.14
6.22
3.63
14.99
4.997
T3-3
7.03
5.82
5.89
8.74
6.25
T4- 5
4.58
3.31
4.94
12.83
4.28
T5-D’grand
4.16
4.29
3.44
11.89
3.96
ANALYSIS OF VARIANCE
SOURCE
DF
SS
MS
F- VALUE
TABULAR
0.05
0.01
Replication
2
7.049
1.524
1.3384
3.84
7.01
Treatment
4
11.573
2.893
1.098ns
Error
8
21.065
2.633
Total
14
39.686
ns – Not significant Coefficient of variation = 32.02%
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
26
Appendix Table 7. Effect of EPNs, on marketable root weight of carrots cv. Tokita
inoculated with root knot nematode, M. incognita
TREATMENTS
REPLICATION
No. of wax moth cadaver
I
II
III
TOTAL
MEAN
T1-0
86.50
65.00
83.00
234.50
78.17
T2-1
105.50
61.00
17.50
183.50
61.17
T3-3
102.00
42.00
33.00
177.00
59.00
T4- 5
41.50
20.50
36.50
98.50
32.83
T5-D’grand
79.00
22.50
75.50
177.00
59.00
ANALYSIS OF VARIANCE
SOURCE
DF
SS
MS
F- VALUE
TABULAR
0.05
0.01
Replication
2
4719.433
2359.717
402574
3.84
7.01
Treatment
4
3156.233
789.058
1.4236ns
Error
8
4434.067
554.258
Total
14
12309.733
ns – not significant Coefficient of variation = 40.57%
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
27
Appendix Table 8. Effect of EPNs, on non- marketable root weight of carrots cv. Tokita
inoculated with root knot nematode, M. incognita
TREATMENTS
REPLICATION
No. of wax moth cadaver
I
II
III
TOTAL
MEAN
T1-0
0
3.50
0
3.50
1.17
T2-1
0
54.00
32.00
86.00
28.67
T3-3
0
48.00
38.00
86.00
28.67
T4- 5
19.50
19.50
34.50
85.00
28.33
T5-D’grand
0
41.00
0
41.00
13.67
ANALYSIS OF VARIANCE
SOURCE
DF
SS
MS
F- VALUE
TABULAR
0.05
0.01
Replication
2
1827.30
913.65
3.3497
3.84
7.01
Treatment
4
1843.27
460.82
1.6895ns
Error
8
2182.03
272.754
Total
14
5852.75
ns – Not significant Coefficient of variation =57.83%
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
28
Appendix Table 9. Effect of EPNs, on non- marketable root weight of carrots cv. Tokita
inoculated with root knot nematode, M. incognita
TREATMENTS
REPLICATION
No. of wax moth cadaver
I
II
III
TOTAL
MEAN
T1-0
0.71
2.00
0.71
3.42
1.14
T2-1
0.71
7.38
5.70
13.79
4.596
T3-3
0.71
6.96
6.20
13.87
4.623
T4- 5
5.76
4.47
5.92
16.00
5.333
T5-D’grand
0.71
6.44
0.71
7.86
2.62
ANALYSIS OF VARIANCE
SOURCE
DF
SS
MS
F- VALUE
TABULAR
0.05
0.01
Replication
2
35.602
17.801
3.9675
3.84
7.01
Treatment
4
36.112
9.028
2.0122ns
Error
8
35.893
4.4487
Total
14
107.607
ns – Not significant Coefficient of variation = 57.83%
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
YADYADOC, ESTRELLA T. APRIL 2011. Effect of Entomopathogenic Nematodes
(EPNs) On Root-knot Nematodes, (Meloidogyne incognita) in Carrot. Benguet State University,
La Trinidad Benguet.
Adviser: Luciana M. Villanueva, PhD.
ABSTRACT
The study was conducted at BIOCON laboratory and greenhouse of Benguet State
University, La Trinidad Benguet from September 2010 to Mach 2011. Three levels of wax larva
infected with approximately 100, 300 and 100 entomopathogenec nematodes (EPNs) were
evaluated to determine their effect on root knot nematode, Melodogyne incognita and on the
growth and yield of carrot, cv. Tokita. Untreated plants and those treated with standard
nematcide, Carbofuran (D’grand) were provided to serve as controls. The treatments were
replicated five times and arranged randomly in the greenhouse using Completely Radomized
Design (CRD).
Application of EPNs did not significantly affect the number of root knot nematodes in the
roots. However, although not significantly different, the number of galls on the secondary root
was generally higher in the control plants than those applied with EPNs.
Likewise, the growth parameters of carrots such as fresh top weight, fresh root weight,
oven dry top weight, marketable and non-marketable root weight, were not significantly affected
by EPN application.
TABLE OF CONTENTS
Page
Bibliography. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
i
Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
i
Table of Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ii
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
REVIEW OF LITERATURE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3
The Crop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3
The Importance of the Crop . . . . . . . . . . . . . . . . . . . . . . . . . . .
3
The Causal Pathogen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3
Symptoms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4
Entomopathogenic Nematodes (EPNs) . . . . . . . . . . . . . . . . . . .
4
Beneficial Effects of EPNs . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5
Biology of Nematode/Bacterium Complex . . . . . . . . . . . . . . .
6
MATERIALS AND METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8
RESULTS AND DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12
Meteorological Condition . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12
Number of Nematodes in Roots . . . . . . . . . . . . . . . . . . . . . . .
12
Number of Galls on Secondary Root . . . . . . . . . . . . . . . . . . . .
13
Fresh Top Weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14
Fresh Root Weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14
Yield . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15
SUMMARY, CONCLUSIONS AND RECOMMENDATIONS . . . .
16
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16
Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17
Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17
LITERATURE CITED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
18
APPENDICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20
1
INTRODUCTION
Carrot is one of the principal crops usually raised in the highlands and thus have
gained great importance. Carrot is a good source of calcium and carotene. It is also a
good source of protein, thiamine and ascorbic acid. It is commonly used as spice and can
be eaten raw (Abuan, 2003).
In Benguet particularly, it is usually produced from October to May, or even the
whole year round depending on the topography of the land, the environment and the
availability of the factors of production.
In the Philippines especially in Benguet, root-knot nematode has already been
found affecting the production of carrots. Depending on the variety and nematode
population densities, the nematode could significantly affect the quality of the tap root
making them commercially undesirable. According to Townshend (1962), many carrots
are discarded in the fresh market and processing industry because of the tap root galling
due to M. hapla infection. The more number of nematodes present/penetrating the roots
the more damage is done on plants. But in the case of susceptible variety, even at low
inoculum level, the quality and quantity of carrots could be significantly reduced.
Farmers however, often encounter problems with carrot plants, despite proper
cultural practices and control of insects, weeds and other diseases. The possibility that
their plants have been attacked by nematodes is great. These tiny organisms cause
primary infection on plants by creating avenues or entry points for other pathogens.
Root knot nematodes, Meloidogyne incognita are obligate parasite capable of
feeding inside the roots. The first of four molts occur in the egg and the nematodes hatch
as second stage juveniles (J2s) which are the infective form. Typically, root knot
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
2
nematode development begins inside the egg. Adult female deposits eggs into a
protective gelatinous matrix, near or just outside the root surface. A single female lays
about 500 to 1500 eggs during her life, which last about two to three months. After the
completion of embryogenesis, the first stage juvenile remains inside the egg until it molts
into second stage – juvenile. After the second stage juvenile hatches from the egg, it
moves freely in the soil in search of suitable host plant (Williamson and Gleason, 2003).
Crop production is the main source of income for most farmers in Benguet.
Control of the damage caused by root knot nematodes in agricultural settings often
requires the use of toxic pesticides. The use of entomopathogenic nematodes (EPNs) as
an alternative to pesticides will be of great help to farmers to improve their income and to
the country in general to increase food supply for the rapidly increasing population.
Reduction of pesticide use will be contributory to ecosystem conservation and protection
and ultimately to sustainable agriculture.
The study aims to evaluate the effect of different levels of EPNs on root knot
nematode, Meloidogyne incognita and on the growth and yield of carrot.
The study was conducted at the BIOCON laboratory and greenhouse of Benguet
State University, La Trinidad, Benguet from September 2010 to March 2011.
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
3
REVIEW OF LITERATURE
The Crop
Carrot (Daucuscarota L.) a biennial plant grown for its edible fleshy root is
usually orange in color, aromatic and sweet. A member of the carrot family
(Umbelloferae), carrot is believed to have originated from the Middle East. It is now
found worldwide, either as a cultivated plant or a weedy wild plant with long, dry roots.
Carrot thrives best on a deep loose loamy soil. The long smooth, slender carrot
desired for fresh marketing can be successfully grown only on deep well drained, high
soils. Experiments in Virginia and New York indicated maximum yields at around pH 6.5
and extremely low yields at pH 5.2 or below. Carrot requires an abundant and well
distributed water supply (Abuan, 2003).
Importance of the Crop
Carrot is rich in carotene, a precursor of Vitamin A, and contains appreciable
quantities of thiamine and riboflavin. Carrot is now gaining in importance because of its
high nutritive value, as stated by quantities of thiamine and riboflavin. It is also used in
many food preparations. It can be a principal ingredient of a dish – like carrot salad. It
gives attractive color and appearance to pickles. It is excellent for garnishing and is very
rich in vitamins.
The Causal Pathogen
Root knot nematodes are the most important plant parasitic nematodes in the
Philippines. It represents a relatively small, but economically important group of obligate
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
4
plant pathogens (Agrios, 1997). It is the most common and widely distributed all over the
country attacking several vegetable crops, field crops, fruit crops and ornamentals.
Meloidogyne spp. is considered to be sedentary endoparasites. They invade the
roots and the development of the vermiform second stage juveniles (J2) depends upon the
modification of the phenotype and function of specific root cells to form specialized cells
that become the permanent source of nutrients for the parasites.
Symptoms
Damage caused by root-knot nematode is best determined by examining the roots
for the presence of galls. Nematode galls should not be confused with the root nodules of
leguminous plants. Nematode galls are characterized by swelling of the roots whereas
root nodules are merely attached to the roots.
Above ground symptoms of plants attacked by root – knot nematodes are stunting
and yellowing of leaves. In some vegetables, the plants may also show wilting during
warmer part of the day as if the plants lack water and eventually die. Plants with fleshy
roots are likely to be more severely damaged by root – knot nematodes than plants with
grass – type roots.
In carrots, symptoms of Meloidogyne spp. infection include galling, large
proliferation of secondary roots and tap root malformation such as severe forking and
stunting (Vrain, 1982 as cited by Belair, 1992).
Entomopathogenic Nematodes (EPNs)
Entomopathogenic nematodes (EPNs) of the families Steinernematidae and
Heterorhabditidae are obligate parasites of a wide range of insects (Fallion et al., 2002).
The infective stage, known as the infective juvenile (IJ), carries a symbiotic bacterium
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
5
that is released following infection of the insect host. Steinernematids are associated with
Xenorhadus spp., and Heterorarhabditids are associated Photorhabdus spp. Once
infection has occurred, the bacteria release anti-microbial agents that help prevent
colonization of the insect cadaver by contaminating fungi and bacteria, and act as a food
source for developing EPNs (Kaya and Gaugler, 1993). The bacteria also produce
stillbene and indole metabolites that are nematicidal to a range of nematode species,
including some plant parasites.
Beneficial Effects of EPNs
Entomopathogenic nematodes have been used successfully to control a number of
compost and soil insects (Gouge and Hague, 1995). These same nematodes have shown
some potential as antagonists to plant parasitic nematodes (PPNs). Application of EPNs
to soil reduced a number of important PPN species including Meloidogyne spp.,
Belonolaimus spp., Tylenchorhyncus spp., and Criconematidae (Grewal et al., 1997).
EPNs tested in laboratory (Bird and Bird, 1986) and greenhouse studies and applied to
tomato plants inoculated with Meloidogyne spp., reduced nematode penetration and egg
production. Perry et.al. (1998) reported a reduction of Globoderarostochiensis
penetration in potato tubers treated with S. carpocapsae in greenhouse and outdoor trials.
A number of interactive effects may be involved in suppression of PPNs and
EPNs. Bird and Bird (1986) proposed the spatial competition at the mutually attractive
root tip may affect root - knot nematode penetration. Ishibashi and Kondo (1986)
suggested increased number of predators from the application of additional nematode
biomass.
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
6
Biology of Nematode/Bacterium Complex
Steinermatids and Heterorhabditids are obligate pathogens in nature. Only the
non-feeding third stage infective juvenile (IJ) or dauer juvenile is capable of surviving
outside the insect host. The IJ carries cells of its bacterial symbiont in its intestinal tract.
After locating suitable host, the IJ invades it through natural openings (mouth, spiracles,
and anus) or thin areas of the host’s cuticle and penetrate into the host hemocoel. The IJ
releases its symbiont, and the bacterium and nematode cooperate to overcome the host’s
immune response (Chen et al., 2004).
The mutualistic bacterium propagates and produces substances that kill the host
and protect the cadaver from colonization by other microorganisms. The nematode
initiates its development, feeding on bacterial cells and host tissues that have been
metabolized by the bacterium and has 1-3 generations, depending on host size. As the
food resources in the host cadaver in search of a new host (Chen et al., 2004).
A major difference between Steinermatids and Heterorhabditids is that the species
in the former group are amphimictic, whilst species in the latter group are hermaphrodites
in the first generation but amphimictic in the following generations. Therefore,
Steirnermatids require at least two IJs, a male and a female, to invade the host to produce
progeny, and Heterorhabditids need only one IJ to penetrate into the host as the resulting
hermaphroditic adult is self-fertile.
Each nematode species is specifically associated with one bacterial symbiotic
species; however, the symbiotic species maybe associated with more than one nematode
species. This specificity operates at 2 levels. First, the best nematode reproduction occurs
on their natural symbiont even though, in some cases, the nematode develops on other
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
7
bacterial species. Second, the natural bacterial symbionts are retained better than other
bacterial species. The nematode is dependent upon the mutualistic bacterium for quickly
killing its insect host; creating a suitable environment for its development, producing
antibiotics that suppress competing microorganisms and transforming the host tissues into
a food source. The bacterium requires the nematode for protection from external
environment, penetration into the host’s hemocoel and inhibition of the host’s
antibacterial proteins (Chen et al., 2004).
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
8
MATERIALS AND METHODS
The study was conducted at the BIOCON Laboratory and greenhouse of Benguet
State University, La Trinidad, Benguet from September 2010 to March 2011.
Source of Inoculum (M. incognita)
The root-knot nematode Meloidogyne incognita was used in the experiment.
These inocula have been maintained in a susceptible variety of garden pea grown in pots
under greenhouse condition in order to have a ready source of inoculum.
Plant Material
Carrot seeds cv. Tokita was directly sown in 7x7x14 cm diameter plastic pots
containing 3 kg heat sterilized soil. Thinning was done six weeks from the time of seed
sowing, maintaining 1 plant per pot. The plants were inoculated a week after thinning.
Preparation of Inocula
Eggs of root-knot nematode were collected from egg masses by dissolution of the
gelatinous matrix. The infected roots were washed thoroughly and cut into small sizes.
The cut roots were shaken for four minutes in stoppered flask containing 5.25% liquid
bleached (Clorox) diluted with four volumes of water making 1% NaOCl solution. The
liquid was poured over rested sieves and collected eggs were washed thoroughly with tap
water to remove the bleach. Suspensions were poured over the blue sieve lined with
tissue paper. Tap water was added reaching the bottom of the sieve. This allowed the
eggs of the root knot nematode to hatch. After 48 hours, J2s were collected in a beaker.
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
9
Source of Entomopathogenic Nematodes
Steinernema sp. All strain IJs were produced in the last instar wax moth Achroia
grisella (Figure 1). EPN infected A. grisella cadavers (hereafter termed as cadavers) were
obtained by infecting each last instar A. grisella larva with approximately 100
Steinernema sp. IJs.
Lesser wax moth infected with EPNs were focused under dissecting microscope
(Figure 2).
Figure 1. Lesser wax moth (Achroia grisella) used for the mass propagation of EPNs
Figure 2. Close up view of EPNs inside Achroia grisella
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
10
Nematode Inoculation
After seedling emergence and when the plants were already well established, all
treatments were inoculated with 1000 second stage juveniles per plant. Four holes were
made in the soil near the plant zone. Using a pipette, the nematode suspension was
distributed in each hole and covered again with soil.
Entomopathogenic nematodes were applied immediately after nematode
inoculation.
The treatments were:
T1 – 0 wax moth cadaver
T2 – 1 wax moth cadaver (approximately100 EPNs)
T3 – 3 wax moth cadavers (approximately 300 EPNs)
T4 – 5 wax moth cadavers (approximately 500 EPNs)
T5 – D’grand- (.4g)
The different treatments were replicated 6 times. The plants were arranged in the
greenhouse using CRD (Figure 3).
Figure 3. Experimental lay-out
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
11
All the cultural management practices for commercial carrot production such as
watering, fertilization control of insect pest and diseases except nematodes were
employed to all treatments to insure the good growth and yield of the plants.
Data Gathered
1. Number of nematodes in soil (200cc). About 200cc of soil was processed
using the modified- tray method.
2. Number of nematodes in roots (2g). Two grams of roots was stained by using
acid-fuchsin and the number of nematodes was counted using a dissecting microscope.
3. Number of galls. The individual galls in the whole root system was counted.
4. Fresh top weight. The vegetative part of the plants was cut at about 6cm from
the soil then weighed.
5. Fresh root weight (g). The roots were washed thoroughly with running water
and weighed separately.
6. Oven dry top weight (g).The upper part of the plant was oven dried at 720 C
for 48 hours.
7. Yield (kg).The marketable and non-marketable roots were weighed separately.
Data Analysis
The data were analyzed statistically using analysis of variance (ANOVA) and
treatment means were separated using Duncan’s Multiple Range Test (DMRT).
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
12
RESULTS AND DISCUSSION
Meteorological Condition
Table 1 shows the average temperature and relative humidity during the conduct
of the study. Apparently, the above conditions were not favorable for the development
and reproduction of root- knot nematodes. According to Hine (1965) the duration of the
life cycle depends on the temperature; when it is maintained at a low level the nematode
numbers increase slowly. All eggs do not hatch simultaneously; some of them hatch only
several months after egg laying resisting cold and dryness. Luc et al. (2004) reported that
one cycle was completed in 19 days at 300C versus 43 days at 21.80C.
Number of Nematodes in Roots
The number of nematodes observed from the 2g root of the different treatments
did not differ significantly. However, higher number of nematodes was recorded from the
roots obtained from the control plants than those applied with different levels of EPN
(Table 2). Surprisingly, no nematode was recovered from the soil which indicates that
perhaps some of the nematodes died and were not able to infect the plants.
Table 1. Average temperature and relative humidity during the conduct of the study
TEMPERATURE
RH
MONTHS
MAXIMUM
OPTIMUM
MINIMUM
(%)
November
24.80
15.20
20.00
86.00
December
25.10
13.60
19.35
92.00
January
24.30
13.00
18.65
85.30
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
13
Number of Galls on Secondary Roots
Table 2 shows the effect of the different treatments on the number of galls in the
secondary roots of carrot. Although not significantly different, the inoculated plants
without EPNs had the highest number of galls compared to those plants treated with
EPNs. Apparently, application of three infected cadavers wax moth (approximately 300
EPNs) was better than those applied with the highest number of wax moth cadavers
(approximately 500 EPNs). On the other hand, the standard nematicide, Carbofuran, (D’
grand) showed the lowest number of galls. Perez and Lewis (2004) reported that M.
hapla inside the roots and egg recovery from seedlings treated with EPNs was
significantly less than those in the control. The low rate of Steirnernema glaseri
suppressed M. incognita penetration into tomato roots and the high rate of S. glaseri
reduced egg production.
On the other hand, since the nematodes were not able to reproduce due to
unfavorable conditions for growth and development, no egg mass was observed in the
roots.
Table 2. Effect of entomopathogenic nematode (EPNs) on the number of galls and
nematodes on the roots
TREATMENTS
NUMBER OF GALLS NUMBER OF NEMATODES IN
ROOTS
0 wax moth cadavers
8.00a
5.17a
1 wax moth cadavers
3.17a
1.67a
3 wax moth cadavers
2.83a
1.67a
5 wax moth cadavers
3.00a
1.33a
D’grand (0.4 g)
0.50a
0.50a
Means followed by similar letters are not significantly different at 5% level using DMRT.
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
14
Fresh Top Weight
Table 3 shows the effect of entomopathogenic nematodes (EPNs) on the fresh top
weight of carrot inoculated with root knot nematode. Evidently, no significant differences
were noted among the treatments. Nevertheless, application of three wax moth cadavers
resulted in the highest fresh top weight (31.83 g) while the lowest (2.33 g) was obtained
from the plants applied with the standard nematicide, D’grand. The same trend was
observed in the oven dry top weight.
Fresh Root Weight
Similar to the fresh top weight, application of EPNs did not significantly affect
the fresh root weight of inoculated carrots (Table 3). Numerically however, plants
inoculated with root-knot nematode and applied with one (1) wax moth cadaver gave the
highest fresh root weight (89.83 g). Unexpectedly, the lowest fresh root weight was
recorded from inoculated carrots applied with five (5) wax moth cadavers (61.17 g).
Table 3. Effect of entomopathogenic nematodes (EPNs) on the growth parameters of
carrot (g)
TREATMENTS
FRESH
FRESH
OVEN DRY MARKETABLE
NON
TOP
ROOT
TOP
ROOT
MARKETABLE
WEIGHT WEIGHT
WEIGHT
(g)
ROOT
0 wax moth cadavers
30.00a
80.83a
5.85a
78.17a
1.17a
1 wax moth cadavers
28.67a
89.83a
4.997a
61.17a
28.67a
3 wax moth cadavers
31.83a
87.67a
6.25a
59.00a
28.67a
5 wax moth cadavers
24.5a
61.17a
4.28a
32.82a
28.33a
D’grand (.4 g)
22.33a
72.67a
3.96a
59.00a
13.67a
Means followed by similar letters are not significantly different at 5% level using DMRT.
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
15
Yield
The effect of EPN on the marketable yield was not significant (Table 3).
Unexpectedly; higher yield was obtained in the untreated compared to the treated plants.
However, lower yield on the treated ones was not attributed to nematode infection but
rather to improper management of the crop that could have affected the growth. Due to
very dense planting, thinning of the plants may have disturbed the main root resulting to
forking of the tap root.
The effect of entomopathogenic nematodes (EPNs) on the non-marketable yield
was also not significant (Table 3). Symptoms on non-marketable root include rotting,
forking and cracking of the tap root.
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
16
SUMMARY, CONCLUSIONS AND RECOMMENDATIONS
Summary
A greenhouse experiment was conducted at the BIOCON laboratory and
greenhouse of Benguet State University, La Trinidad, Benguet from September 2010 to
Mach 2011to determine the effect of entomopathogenic nematodes (EPNs) on root- knot
nematode, (Meloidogyne incognita) and on growth and yield of carrot.
Application of 1, 3 and 5 wax moth cadavers infected with EPNs in carrot cv.
Tokita inoculated with 1000 juveniles of Meloidogyne incognita did not significantly
affect the number of nematodes in the roots. The absence of nematodes in the soil and the
presence of very few nematodes in the roots indicate that some of the nematodes died and
were not able to infect the plants. This was attributed to unfavorable weather condition
that could have affected the growth and development of root-knot nematodes.
Although not significantly different, the number of galls in the secondary root was
generally higher in the untreated control than those applied with entomopathogenic
nematodes (EPNs). Because of very low temperature, the nematode development and
reproduction was delayed, thus no egg masses were produced.
Likewise no significant differences were also noted on the growth parameters of
carrot: fresh top weight, fresh root weight, oven dry top weight, marketable and non-
marketable yield.
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
17
Conclusions
1. Results of the experiment shows that application of different levels of wax
moth cadavers infected with EPNs did not significantly affect the number of root knot
nematodes that penetrated the roots including the number of galls. Since the temperature
was very low, the growth and development of both the root knot nematode and EPNs
were delayed. Thus, no egg mass was also detected.
2. Because of the above reason, the growth and yield parameters of carrot were
also not significantly affected by EPN application.
Recommendations
Since the experiment was greatly affected by unfavorable temperature additional
studies are necessary to fully evaluate the efficacy of entomopathogenic nematodes
against root-knot nematode in carrot. It is recommended that studies should be done
during summer when the temperature is conducive for the growth and development of
both RKN and EPNs in order to have more conclusive results.
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
18
LITERATURE CITED
ABUAN, M. M. 2003. Response of two carrot (Daucuscarota L.) cultivars to varying
levels of root-knot nematode. BS Thesis. (Benguet State University. La Trinidad,
Benguet. P. 12.
AGRIOS, G. N. 1997. Plant Pathology. 4th Edition. San Diego, California. Pp. 565-567.
BIRD, A. F., and J. BIRD. 1986. Observations on the use of entomopathogenic
nematodes as means of biocontrol of root-knot nematodes. International Journal
of Parasitology 16:511-516.
BELAIR, G. 1992. Effect of Cropping Sequences on Population Densities of
Meloidogyne hapla and Carrot Yield in Organic Soil. Journal of Nematology. 24
(3): 450-456.
CHEN, Z., S. CHEN and D.W. DICKSON. 2004. Nematology-Advances and
Perspective, CABI Publishing. Pp.1098-1099.
FALLION, D. J. KAYA, R. GAUGLER and B. S. SIPES. 2002. Effect of
Entomopathogenic Nematodes on Meloidogyne incognita on Tomato and
Soybean. Journal of Nematology 34(3):239.
GREWAL, P. S., W. R. MARTIN, R. W. MILLER and E. E. LEWIS. 1997. Suppression
of plant-parasitic nematode populations in turf grassby entomopathogenic
nematodes. Nematology1:735-743.
GOUGE, D. H. and N. HAGUE. 1995. Glasshouse control of fungus gnats, Bradysia
pauperaon fuchsias by Steinermafeltiae. Fundamental and Applied Nematology
18:77-80.
HINE, R. B., O. V. HOLTZMAN, and R. D. RAABE. 1965. Disease of Carrot in Hawaii.
Hawaii Agric. Exp. Stn. Bull.136, Univ. of Hawaii. P. 26.
ISHIBASHI, N., and E. KONDO. 1986. Steinernemafeltiae (DD-136) and S. glaseri:
Persistence in soil and bark compost and their influence on native nematodes.
Journal of Nematology 18:310-316.
KAYA, H. K., and R. GAUGLER. 1993. Entomopathogenic nematodes. Annual Review
of entomology 38:181-206.
LUC, M., RICHARD.S., J. BRIDGE. 2005. Plant parasitic Nematodes in Subtropical and
Tropical Agriculture.CABI Publishing P. 331.
PEREZ, E. E., and E. E. LEWIS. 2004. Entomology Department,Virginia Tech,
Blacksburg, VA 24061,USA Biological Control. Vol 30. Pp .336-341
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
19
PERRY. R. N., HOMONICK. W. M., BEANE. J., BRISCOSE. B., 1998. Effect of the
entomopathogenic nematodes, Steinermafeltiae and S. carpocapsae, on the potato
cyst nematode, Globoderarostochiensis, in pot trials. Bocontrol Science and
Technology 8:175-180.
TOWNSHEND, J. L. AND T. R. DAVIDSON. 1962. Some Weed Hosts of the Northern
Root- knot Nematode Meloidogyne hapla (Chiwood,1948) Ontario, Canada.
Journal of Botany. 17:154-66.
WILLIAMSON, V. M. and C. A. GLEASON. 2003. Plant-nematode Interactions.
CurrentOpinion in Plant Biology. 6:327-333.
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
20
APPENDICES
Appendix Table 1. Effect of EPNs, on the number of nematodes in roots (2g) of carrots
cv. Tokita inoculated with root knot nematode, M. incognita
TREATMENT
REPLICATION
No. of wax moth cadaver
I
II
III
TOTAL
MEAN
T1-0
14.5
1.00
0.00
15.50
5.17
T2-1
0.50
1.00
3.50
5.00
1.67
T3-3
2.00
1.00
2.00
5.00
1.67
T4- 5
0.50
1.50
2.00
4.00
1.33
T5-D’grand
1.00
0.00
0.50
1.50
0.50
ANALYSIS OF VARIANCE
SOURCE
DF
SS
MS
F-VALUE
TABULAR
0.05
0.01
Replication
2
21.333
10.67
0.7232
3.84
7.01
Treatment
4
38.767
9.692
0.6602ns
Error
8
117.433
14.679
Total
14
177.433
ns – Not significant Coefficient of variation = 185.26%
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
21
Appendix Table 2. Effect of EPNs, on the number of nematodes in roots (2g) of carrots
cv. Tokita inoculated with root knot nematode, M. incognita
TREATMENTS
REPLICATION
No. of wax moth cadaver
I
II
III
TOTAL
MEAN
T1-0
3.87
1.22
0.71
5.80
1.93
T2-1
1.00
1.22
2.00
4.22
1.41
T3-3
1.58
1.22
1.58
4.38
1.46
T4- 5
1.00
1.41
1.58
3.99
3.00
T5-D’grand
1.22
0.71
1.00
2.93
0.997
ANALYSIS OF VARIANCE
SOURCE
DF
SS
MS
F-VALUE
TABULAR
0.05
0.01
Replication
2
1.41
0.43
0.58
3.84
7.01
Treatment
4
0.85
0.35
0.4838ns
Error
8
5.85
0.73
Total
14
8.113
ns – Not significant Coefficient of variation = 60.17%
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
22
Appendix Table 3. Effect of EPNs, on the number of galls of carrots cv. Tokita
inoculated with root knot nematode, M. incognita
TREATMENTS
REPLICATION
No. of wax moth cadaver
I
II
II
TOTAL
MEAN
T1-0
4.58
2.00
0.71
7.29
2.43
T2-1
1.22
1.73
2.55
5.50
1.83
T3-3
2.12
1.58
1.73
5.43
1.81
T4- 5
1.22
2.24
2.12
5.36
1.79
T5-D’grand
0.71
1.00
2.93
0.98
ANALYSIS OF VARIANCE
SOURCE
DF
SS
MS
F-VALUE
TABULAR
0.05
0.01
Replication
2
0.512
0.256
0.218
3.84
7.01
Treatment
4
3.212
0.803
0.685ns
Error
8
9.376
1.172
Total
14
13.090
ns – Not significant Coefficient of variation = 61.26%
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
23
Appendix Table 4. Effect of EPNs, on the fresh top weight of carrots cv. Tokita
inoculated with root knot nematode, M. incognita
TREATMENTS
REPLICATION
No. of wax moth cadaver
I
II
III
TOTAL
MEAN
T1-0
25.50
31.50
33.00
90.00
30.00
T2-1
28.00
38.00
20.00
86.00
28.67
T3-3
27.00
40.50
28.00
95.50
31.83
T4- 5
26.50
20.00
27.00
73.50
24.50
T5-D’grand
21.50
23.50
22.00
67.00
22.33
ANALYSIS OF VARIANCE
SOURCE
DF
SS
MS
F- VALUE
TABULAR
0.05
0.01
Replication
2
78.633
39.312
1.2034
3.84
7.01
Treatment
4
186.233
46.558
1.4251ns
Error
8
261.367
32.671
Total
14
526.233
ns – Not significant Coefficient of variation = 21.25%
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
24
Appendix Table 5. Effect of EPNs, on the fresh root weight of carrots cv. Tokita
inoculated with root knot nematode, M. incognita
TREATMENTS
REPLICATION
No. of wax moth cadaver
I
II
III
TOTAL
MEAN
T1-0
86.50
68.50
87.50
242.50
80.83
T2-1
105.00
115.00
49.50
269.50
98.86
T3-3
72.50
90.00
71.00
263.00
87.67
T4- 5
72.50
57.00
54.00
183.50
61.17
T5-D’grand
79.00
63.50
75.50
218.00
72.67
ANALYSIS OF VARIANCE
SOURCE
DF
SS
MS
F- VALUE
TABULAR
0.05
0.01
Replication
2
1156.633
578.317
1.94
3.84
7.01
Treatment
4
1657.100
414.275
1.39ns
Error
8
2380.200
297.525
Total
14
5193.933
ns – Not significant Coefficient of variation = 21.99%
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
25
Appendix Table 6. Effect of EPNs, on the oven dry top weight of carrots cv. Tokita
inoculated with root knot nematode, M. incognita
TREATMENTS
REPLICATION
No. of wax moth cadaver
I
II
III
TOTAL
MEAN
T1-0
9.20
2.58
5.78
17.56
5.76
T2-1
5.14
6.22
3.63
14.99
4.997
T3-3
7.03
5.82
5.89
8.74
6.25
T4- 5
4.58
3.31
4.94
12.83
4.28
T5-D’grand
4.16
4.29
3.44
11.89
3.96
ANALYSIS OF VARIANCE
SOURCE
DF
SS
MS
F- VALUE
TABULAR
0.05
0.01
Replication
2
7.049
1.524
1.3384
3.84
7.01
Treatment
4
11.573
2.893
1.098ns
Error
8
21.065
2.633
Total
14
39.686
ns – Not significant Coefficient of variation = 32.02%
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
26
Appendix Table 7. Effect of EPNs, on marketable root weight of carrots cv. Tokita
inoculated with root knot nematode, M. incognita
TREATMENTS
REPLICATION
No. of wax moth cadaver
I
II
III
TOTAL
MEAN
T1-0
86.50
65.00
83.00
234.50
78.17
T2-1
105.50
61.00
17.50
183.50
61.17
T3-3
102.00
42.00
33.00
177.00
59.00
T4- 5
41.50
20.50
36.50
98.50
32.83
T5-D’grand
79.00
22.50
75.50
177.00
59.00
ANALYSIS OF VARIANCE
SOURCE
DF
SS
MS
F- VALUE
TABULAR
0.05
0.01
Replication
2
4719.433
2359.717
402574
3.84
7.01
Treatment
4
3156.233
789.058
1.4236ns
Error
8
4434.067
554.258
Total
14
12309.733
ns – not significant Coefficient of variation = 40.57%
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
27
Appendix Table 8. Effect of EPNs, on non- marketable root weight of carrots cv. Tokita
inoculated with root knot nematode, M. incognita
TREATMENTS
REPLICATION
No. of wax moth cadaver
I
II
III
TOTAL
MEAN
T1-0
0
3.50
0
3.50
1.17
T2-1
0
54.00
32.00
86.00
28.67
T3-3
0
48.00
38.00
86.00
28.67
T4- 5
19.50
19.50
34.50
85.00
28.33
T5-D’grand
0
41.00
0
41.00
13.67
ANALYSIS OF VARIANCE
SOURCE
DF
SS
MS
F- VALUE
TABULAR
0.05
0.01
Replication
2
1827.30
913.65
3.3497
3.84
7.01
Treatment
4
1843.27
460.82
1.6895ns
Error
8
2182.03
272.754
Total
14
5852.75
ns – Not significant Coefficient of variation =57.83%
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
28
Appendix Table 9. Effect of EPNs, on non- marketable root weight of carrots cv. Tokita
inoculated with root knot nematode, M. incognita
TREATMENTS
REPLICATION
No. of wax moth cadaver
I
II
III
TOTAL
MEAN
T1-0
0.71
2.00
0.71
3.42
1.14
T2-1
0.71
7.38
5.70
13.79
4.596
T3-3
0.71
6.96
6.20
13.87
4.623
T4- 5
5.76
4.47
5.92
16.00
5.333
T5-D’grand
0.71
6.44
0.71
7.86
2.62
ANALYSIS OF VARIANCE
SOURCE
DF
SS
MS
F- VALUE
TABULAR
0.05
0.01
Replication
2
35.602
17.801
3.9675
3.84
7.01
Treatment
4
36.112
9.028
2.0122ns
Error
8
35.893
4.4487
Total
14
107.607
ns – Not significant Coefficient of variation = 57.83%
Effect of Entomopathogenic Nematodes (EPNs) On Root-knot Nematodes,
(Meloidogyne incognita) in Carrot. YADYADOC, ESTRELLA T. APRIL 2011
Document Outline
- Effect of Entomopathogenic Nematodes(EPNs) On Root-knot Nematodes, (Meloidogyne incognita) in Carrot
- BIBLIOGRAPHY
- TABLE OF CONTENTS
- INTRODUCTION
- REVIEW OF LITERATURE
- MATERIALS AND METHODS
- RESULTS AND DISCUSSION
- SUMMARY, CONCLUSIONS AND RECOMMENDATIONS
- LITERATURE CITED