ABSTRACT
BIBLIOGRAPHY
WAKAT, VERON A. APRIL 2008. Influence of Root-Knot Nematode
(Meloidogyne incognita) on the severity of Fusarium wilt on Strawberry ( Fragaria x
ananassa Duch). Benguet State University, La Trinidad, Benguet.
Adviser: Luciana M. Villanueva, Ph.D.
ABSTRACT
The effect of root-knot nematode, Meloidogyne incognita on the severity of
Fusarium wilt of strawberry was evaluated under greenhouse conditions. Inoculation of
strawberry cultivar Sweet Charlie with 1,000 second stage juvenile of root-knot nematode
in combination with Fusarium sp. resulted in greater incidence and severity of Fusarium
wilt. However, this was not significantly different from plants inoculated with the fungus
alone. Fresh root weight was significantly reduced when plants were inoculated with
fungus alone and the combination of nematode and fungus. However, no significant
effect was noted on the fresh top weight.
A significant number of second, third and forth stage juveniles of root-knot
nematode was recovered from the roots of plants inoculated with nematode alone but
they did not develop into adult females. On the other hand, significantly less number of
J2, J3 and J4 was noted in the roots of plants inoculated with the combination of
nematode and the fungus.
The results imply that strawberry cultivar Sweet Charlie is not a suitable host of
M. incognita. Thus, the expected increase in the severity of Fusarium wilt due to
inoculation of nematode plus fungus was not observed in the present investigation despite
the susceptibility of the strawberry cultivar to the fungal pathogen.
ii
TABLE OF CONTENTS
Page
Bibliography. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
Abstract. . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
Table of Contents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
REVIEW OF LITERATURE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
MATERIALS AND METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
A. Root- knot Nematode( Meloidogyne incognita) . . . . . . . . . . . . 7
Source of nematode Inocula. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Standardization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Inoculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
B.Fusarium wilt. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Isolation of the Organism. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Standardization of the Inoculum. . . . . . . . . . . . . . . . . . . . . . . . . . 8
Inoculation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
RESULTS AND DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Disease Severity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Fresh Root Weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Fresh Top Weight. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Number of J2 in 3 g of Root . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Number of J3-J4 in 3 g of Root . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Total Number of Nematode in the Soil . . . . . . . . . . . . . . . . . . . . . . . . . 15
iii
SUMMARY, CONCLUSION AND RECOMMENDATION . . . . . . . . . . . 20
LITERATURECITED. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
APPENDICES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
iv
INTRODUCTION
In Baguio and Benguet, particularly in La Trinidad strawberry, (Fragaria x
ananassa Duch) production is one of the sources of farmers’ income. It is grown for its
edible red fruits which are either eaten as fresh and flavoring purposes. It is highly demanded
by tourists, processing factories like Magnolia, Nestle as well as local consumers (Flores,
2007). It contains ellagic acid, which is a potent antioxidant. Strawberries are highly
perishable, and vitamin C is present on the berries (Esiong, 2004).
Several strawberry varieties were earlier introduced in the highland; which includes
Tioga, Solana, Royal Gem, Mission bells and Fukuba. These varieties are no longer planted
in the locality. The most widely grown variety today is Sweet Charlie.
Recent survey showed the presence of Fusarium spp. in strawberry growing areas
in Baguio and Benguet. This fungus usually enters its host through feeder roots, and then it
multiplies and colonizes the vascular system. Infection may occur at any time during the life
of the plant. The disease is more severe when air and soil temperature are 78˚ to 90˚ F and is
more likely to occur in poorly drained soil (Tarr, 1972).
Meloidogyne has the greatest capability in predisposing plants to attack by
Fusarium spp. Interactions between Meloidogyne spp. and Fusarium oxysporum have been
reported in many crops (Mai and Abawi, 1987). Most papers on this interaction reported the
use of inoculum at either specified concentrations or densities that were unnaturally high.
Roots commonly were wounded, either by cutting, transplanting, or making inoculation holes
in the soil. Studies of the effects of different inoculum densities have demonstrated an
increased in susceptibility to Fusarium wilt at moderate or high levels of Meloidogyne spp.
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
2
and moderate levels of F. oxysporum in watermelon (Summer and Johnson, 1973) and cotton
(Starr and Garbey et. al, 1989).
Objectives of the Study
1. To determine the influence of root-knot nematode (Meloidogyne incognita) on
the severity of Fusarium wilt in strawberry, and
2. To determine the effect of Fusarium sp. on the reproduction/ population of M.
incognita.
Time and place of the study
The study was conducted at the BIOCON laboratory and greenhouse of
Horticultural Research and Training Institute, (HORTI) Benguet State University, La
Trinidad, Benguet.
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
REVIEW OF LITERATURE
The Host Plant
Strawberry cultivar Sweet Charlie is from the University of Florida (UF). It is
resistant to anthracnose fruit rot. The fruit has distinctly sweet flavor due to high sugar/
acid ratio. Its external fruit color is orange red and internal color is orange streaked with
white. The fruit is generally less firm than the fruit of Oso Grande and have average size
of 17 g, which is similar to that of Selva but less than that of Oso Grande. Fruit has a
larger calyx compared to the fruit of other cultivars grown in Florida (Anonymous,
2002).
The Pathogen
Fusarium wilt. Fusarium wilt is a soil borne fungal disease that affects a wide
variety of herbaceous plants, causing wilting and death.
Fusarium is a large genus of filamentous fungi widely distributed in soil and in
association with plants. Most species are harmless saprobes and are relatively abundant
members of the soil microbial community.
Disease cycle
The
Fusarium fungus survives and may actually increase in a number of soil
types for many years, independent of any host plants. This ability to survive eliminated
any normal rotation program on general sanitation as an effective control measure. The
appearance and severity of the disease are increased when air and soil temperature
average at this rise at point. The fungus grows most rapidly and the disease is most severe
at temperature 80 to 85˚F (26˚ to 29ْ˚ C). The Fusarium wilt fungus invades the plant
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
4
through the young rootlets or wounds in the older roots at transplanting time or later. The
fungus moves directly to the water- conducting tissues (xylem) and they progresses up
the stem into the leaves. The fungus colonizes the xylem tissues and does not invade
other tissues until part or the entire plant dies. The fungus produces its spore both inside
and outside the affected stems.
Life Cycle
According to Agrios (1988), Fusarium produces one to two- celled thick- walled
clamydospores that can withstand drought and low temperature. The fungus thrives on
dead plant tissues and can over winter as mycelium or spores on infected tissues or seeds.
The spores are early spread by air, contaminated equipment and water
Species
of
Fusarium produces two types of conidia that are termed macroconidia
and microconidia (Alexopolus, 1996).
Persistence and transmission
Fusarium
wilt can persist in most soils indefinitely because of its ability to
colonize the roots of a number of weeds and to produce resistant spore structure.
Symptoms
Symptoms of black root rot usually begin in the first fruiting year. The injury is
most noticeable in low or compacted soil of a field where drainage is poor. Strawberry
plants with black root rot show a general lack of vigor with poor runner growth and small
berries. Plants may collapse when water demand is high such as during spring growth,
during or after fruiting, or during drought stress (Ellis et al., 2005).
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
5
Site Selection
To reduce infection of Fusarium sp., future planting site should be selected at
least one year before planting. Soil drainage should be good. Avoid low- lying areas that
have a tendency to be poorly drained (Pritts et al., 1991).
Control
Crop rotation is a great tool for controlling the disease as well, however, it is
difficult to control if the space is limited because the spore may persist for as long as six
years in the soil. In addition, the planting of host crops like eggplant, peppers, potatoes,
strawberries and raspberries may not be avoided.Plant only certified, disease free
transplants in fertile, well- drained soil .
Meloidogyne incognita Root- knot nematodes represent a relatively small but
economically important group of obligate plant pathogens (Agrios, 1997). They are
endoparasite with an interesting life cycle (Akthmar and Malik (N.D.)). They have
evolved very specialized and established complex feeding relationship with their host
plants. Juveniles hatch from egg after already having molted once. These second stage
juveniles travel though the soil until they find plant tissue where they can penetrate and
feed on, usually on tender root tip (Ferraz and Brown, 2002).
Symptoms
Plants infected with root-knot nematode exhibit leaf chlorosis, stunting and less
blossom. Galling is also observed and the degree depends on the population of the
nematode in the soil.
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
6
Survival of Nematodes
Nematode population is influenced by many factors. Soil moisture is one of the
major factor affecting the nematode population, especially when rapid and extreme
changes occur in the soil environment (HARRDEC, 1996). Since nematodes are aquatic
animals, they require film of water coating soil particle for motility and survival (Agrios,
1997).
Control
Solarization can effectively suppress most species of nematode. This is an non-
chemical technique in which transparent polyethylene film is laid over raised beds for 2-
6 period to heat non- cropped soil to temperature lethal to nematodes and other soil borne
pathogens (Noling,1995).
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
MATERIALS AND METHODS
The study was conducted at the BIOCON Laboratory and greenhouse of
Horticultural Research and training Institute, Benguet State University, La Trinidad,
Benguet. There were four treatments, which were replicated three times. Rice hull and
sand were mixed and heat- sterilized prior to inoculation.
A. Root-Knot Nematode (Meloidogyne incognita)
Source of Nematode Inocula
Galled roots were collected from single egg mass culture and washed with tap
water to remove the adhering soil particles. These galled roots containing egg masses of
M. incognita were chopped into 1- 2 cm pieces and placed in 250 ml flasks. The eggs
were allowed to disperse by dissolving the gelatinous matrix using 1% NaOCL solution
(commercial bleach) in flasks which were vigorous by shaken (Shurtleff and Averre,
2000).
Standardization
Nematodes in water suspension were standardized by determining the number of
eggs in a known volume. The suspension was agitated by stirring and blowing of pipette
to make air bubbles while an aliquot was being withdrawn to ensure the even distribution
of nematodes. When the tip of the pipette is midway between the top and the bottom of
the liquid, an aliquot was immediately drawn and released into a counting dish. The
number of eggs in a 1 ml aliquot was counted under a stereomicroscope and multiplied
by the total volume of the suspension.
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
8
Inoculation
One thousand (1,000) eggs were used for inoculation per plant (Villanueva et. al,
2007).
B. Fusarium wilt.
Isolation of the Organism
Infected strawberries were collected from the field and washed thoroughly to
remove the adhering soil particles. The roots were cut measuring 1 cm and surface-
sterilized with 1% NaOCL, blot dry and washed three times with sterile distilled water.
Sections of infected roots were placed in previously plated kidney bean agar.
Standardization of the Inoculum
Suspension containing conidia was prepared and spore concentration was
estimated using a haemacytometer. One ml of conidial suspension was sucked using a
micropipette and deposited on the ridge of the hemacytometer. After the suspension had
flown automatically to the counting chamber, conidia counting was done in five squares
of the nine squares labeled A which contains 16 small squares. Standardization was done
three times. The average count of the five squares per trial was multiplied with 50,000 to
obtain the total spore/ ml.
Inoculation
One week after the inoculation of the root- knot nematode (M. incognita), the
plants were inoculated with Fusarium sp. using the inoculum level of 1x 106 spore/ ml.
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
9
The different treatments were the following:
T1- Uninoculated
T2- Root-knot nematode (M. incognita) alone
T3- Fusarium sp. alone
T4- Root-knot nematode (M. incognita) + Fusarium sp.
Data Gathered
1. Disease severity. plants were assessed for Fusarium wilt severity using the
rating scale below:
Rating Description
1 normal; no infection
2 .5- 5 cm discoloration
3 6- 10 cm discoloration
4 11- 20 cm discoloration
5 31- 40 cm discoloration
6 41- 60 cm discoloration
7 61- 80 cm discoloration
8 81- 100 cm discoloration
2. Top weight (g). This refers to the weight of the upper portion of the plant after
harvest.
3. Root weight (g). This refers to the weight of the root after harvest.
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
10
4. Number of nematodes in 3 g of root. Population counts of nematodes in feeding
position were made from 3 g roots per treatment. Roots were stained in acid fuchsin
glycerol to facilitate counting.
5. Number of nematodes in 200 g of soil (g). To determine whether the population
of root knot decreased or increased, 200 g of soil samples were obtained from each pot
and processed using the modified Baermann-tray technique. The nematodes were
collected separately in 150-ml capacity Erlenmeyer flasks. The suspensions were allowed
to stand at least 3 hours at room temperature and the excess water in the flasks was
reduced to 50 ml by suction using a pipette. The nematodes were transferred to 50 ml
capacity test tubes and were again allowed to stand at least 1 hour for nematodes to settle
at the bottom. The nematodes were counted under a stereoscopic microscope.
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
RESULTS AND DISCUSSION
Disease Severity
Inoculation
of
Fusarium sp. and Meloidogyne incognita on strawberry cultivar
Sweet Charlie resulted in wilting and sudden death of the plant (Fig. 1). However, it did
not significantly differ with plants inoculated with Fusarium alone. Plants inoculated
with nematode also showed vascular discoloration but significantly lower than those
inoculated with the fungus and the combination of fungus and nematode. On the other
hand, the uninoculated plants did not show vascular discoloration and wilting typical of
Fusarium wilt infection. This was significantly different from the other treatments.
Fresh Root Weight
Plants inoculated with Fusarium wilt alone resulted in significantly lower fresh
top weight (Figure 2). Although not significantly different from plants inoculated with
the combination of the fungus and nematode and uninoculated control, those inoculated
with root-knot nematode alone has the highest fresh root weight. Nevertheless, this was
significantly higher than those plants inoculated with Fusarium sp. alone.
Fresh Top Weight
Inoculation
of
root-knot
nematode alone, combination of nematodes and Fusarium
sp. and fungus alone did not significantly affect the fresh top weight of strawberry (Fig.
3).
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
12
8
a
7
a
r
i
t
y
6
5
e
ve
S
4
b
se
3
2
a
i
sea
D
1
0
Control
root-knot
Fusarium
Root-knot
nematode
sp.alone
nematode
alone
+Fusarium
sp.
Treatment
Fig. 1. Effect of root-knot nematode (M. incognita) and Fusarium sp. on disease severity.
3.5
a
3
a
2.5
b
ab
2
e
i
ght
w
1.5
oot
R
1
0.5
0
Control
root-knot
Fusarium
Root-knot
nematode alone
sp.alone
nematode
+Fusarium sp.
Treatment
Fig. 2. Effect of root-knot nematode (M. incognita) and Fusarium sp. onweight.
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
13
2.5
a
a
2
a
g)
(
1.5
a
e
i
ght
1
Top W
0.5
0
Control
root-knot
Fusarium
Root-knot
nematode alone
sp.alone
nematode
+Fusarium sp.
Treatment
Fig. 3. Effect of root-knot nematode (M. incognita) and Fusarium sp. on fresh top weight
t
o
180
o
a
160
f
R
o
140
g
120
3
100
2
in
80
f
J
60
40
e
r
o
b
20
c
c
b
m
u
0
N
Control
root-knot
Fusarium
Root-knot
nematode alone
sp.alone
nematode
+Fusarium sp.
Treatment
Fig. 4. Effect of Effect of root-knot nematode (M. incognita) and Fusarium sp. on the
number of J2 in 3 g of roots
Number of J2 in the Root
Figure 4 shows the effect of the different treatments on the number of second
stage juveniles in the root of strawberry. Apparently, the highest population of J2 was
noted in plants inoculated with root-knot nematode alone. This was significantly different
from those inoculated with the combination of the nematode and the fungus. No
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
14
nematode was recorded from the uninoculated plants and those inoculated with Fusarium
sp. alone.
Number of J3 and J4 in the Root
The effect of the different treatments on the number of third and fourth stage
juveniles in 3 g root is shown in Figure 5. The highest nematode count was noted in
plants inoculated with root-knot nematode alone. This was significantly different from
plants inoculated with the combination of nematode and the fungus. There was no
nematode recovered from the control, plants and those inoculated with Fusarium sp.
alone.
The absence of adult female nematode in the roots indicates that the nematode
failed to develop up to maturity. According to Powell et. al (1960) fungal colonization of
giant cells(the source of food for the nematode) and xylem is common in fungus-root
knot interactions. The fact that the structure of the giant cell changes prior to fungal entry
implies that translocatable fungal secretions rather than the penetrating hyphae initially
modify and eventually kill the giant cells (Fattah and Webster, 1983). In addition to this
fungus-induced/produced factor in the Meloidogyne-Fusarium disease complex on
tomato, the developing nematode produces a factor or induces the plant to produce such a
factor that is transmitted upward through the plant and breaks the fungal resistance (i.e.
predisposes) of the host to Fusarium. The fungus develops and its secretions cause a
progressible necrosis of the giant cell which, in turn, causes the nematode to stave to
death.
Generally, the increase in the severity of Fusarium wilt in the strawberry due to
M. incognita was not observed in the present study. This could be due to the following
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
15
reasons. First, strawberry is not a suitable host of M. incognita and second , Fusarium sp.
has an adverse effect on the development and reproduction of the nematode.
Previous reports have shown that strawberry is not a suitable host of M. incognita.
However, in Huelva, Spain M. incognita was one of the root knot nematodes recover
from strawberry samples aside from M.hapla,M.arenaria and Meloidogyne sp.(Vega et.
al 2002). Early observations of nematode- fungal interaction suggested that they were
due to the nematode providing a ready means of entry into the host for the fungus.
Undoubtedly, this occurs when root- browsing nematode cause superficial root injury and
so enhance fungal asses and secondary pathogenicity of the roots (Webster, 1985).
The
Meloidogyne- Fusarium interaction has been extensively studied because of
its significance on major world crops, such as cotton (Sasser, 1972) and tobacco (Milne,
1972). The extent of the disease interaction is greatly influenced by range of factors. For
instance, there is more extensive Fusarium colonization of the plant tissues as the number
of developing Meloidogyne increases. Moreover, symptom expression, as a manifestation
of disease interaction is greater in “young” than in “old” plants (Pitcher, 1974).
Total Number of Nematodes in the soil
Figure 6 shows the number of nematodes recovered from the soil. No significant
difference was noted between those inoculated with nematode alone and the combination
of root-knot nematode and Fusarium sp. As expected, no nematodes were obtained from
the inoculated pots and those applied with Fusarium sp. alone.
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
16
t
o
o
120
a
f
r
o
100
g
3
80
60
3
-
J
4
in
f
J
40
e
r
o
20
b
b
b
b
m
0
u
N
Control
root-knot
Fusarium
Root-knot
nematode alone
sp.alone
nematode
+Fusarium sp.
Treatment
Fig. 5. Number of third and fourth stage juveniles in 3 g of roots as affected by the
different
treatments
a
1600
g of
1400
n 3
i
1200
1000
a
t
ode
m
800
ne
r
oot
600
r
of
400
be
200
c
c
b
0
a
l
num
Control
Root-knot
Fusarium
Root-knot
Tot
nematode
sp.alone
nematode +
alone
Fusarium sp.
treatment
Fig. 6. Total number of nematodes in 3 g roots as affected by the different treatments.
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
17
f
2.5
o
0
0
g
2
2
e
in
1.5
d
l
a
t
o
1
Soi
e
m
f
N
0.5
e
r
o
b
0
m
Control
root-knot
Fusarium
Root-knot
u
N
nematode
sp.alone
nematode
alone
+Fusarium sp.
Treatment
Fig.7. Number of nematodes in the soil
Fig. 8. Second stage juveniles (J2) of M. incognita inside the roots of strawberry. Note the
absence of mature females.
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
18
Fig.9. Pure culture of Fusarium sp. isolated from infected strawberry.
Fig.10. Macroconidia and microconidia of Fusarium sp.
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
19
A
B
C
D
Fig.11. Root systems of strawberry cultivar Sweet Charlie A – Uninoculated control, B –
inoculated with M. incognita alone; C – Inoculated with Fusarium sp. alone and
D – Inoculated with Fusarium sp. + M. incognita
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
SUMMARY, CONCLUSION AND RECOMMENDATION
Summary
A greenhouse experiment was conducted to determine the influence of root-knot
nematode (Meloidogyne incognita) on the severity of Fusarium wilt in strawberry
cultivar Sweet Charlie. Inoculation of 1,000 second stage juveniles (J2) of M. incognita
did not significantly enhance the incidence and severity of Fusarium wilt of strawberry.
Inoculation of root-knot nematode alone and the combination of root-knot
nematode and Fusarium sp. resulted in significant reduction in fresh root weight but not
in fresh top weight.
A significant number of second, third and fourth stage juveniles of root-knot
nematode was recovered from the roots of plants inoculated with nematode alone but
they did not develop into adult females. On the other hand, significantly less number of
J2, J3 and J4 was noted in the roots of plants inoculated with the combination of root-
knot nematode and Fusarium sp. indicating the adverse effect of the fungus on the
growth and development of the nematode.
Conclusion
Based on the results obtained, strawberry cultivar Sweet Charlie is not a suitable
host to root-knot nematode. Because of the above reason, the nematode was not able to
enhance the incidence and severity of Fusarium wilt despite the susceptibility of
strawberry cultivar Sweet Charlie to Fusarium sp.
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
21
Recommendations
Further studies are therefore necessary using another species of Meloidogyne
(preferably M. hapla) to fully evaluate the influence of the above nematode on the
severity of Fusarium wilt in strawberry. Studies on the effect of varying nematode
population densities and inoculation methods which minimize wounding are also
recommended.
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
LITERATURE CITED
AGRIOS, G.N. 1988. Plant Pathology. 3rd edition. San Diego, California: Academic
Press. Pp. 21 – 26.
AGRIOS, G.N. 1997.Plant Pathology. 4th edition. San Diego, California. Pp565-567.
AKHMAR, M. and A. MALIK.N.D. Role of Organism, Soil Amendment and soil
organism in biological control of plant parasitic nematode Journal 23: 153.
ALEXOPOULOS,C.J. 1996. Introductory Mycology. 4th edition. New York: John Wiley
and Sons, Inc. Pp.244.
ANONYMUOS, 2002. Lansen Canyon Nursery Commercial Strawberry Growers.
Retrieved April 28, 2007 from http://www.lansencanyoonursery. /comm.
Varieties
ELLIS, M.A. 1995. Organic small fruit disease management guideline department of
Plant Pathology at the Ohio State University. Pp. 30 – 35.
ESIONG, M.S. 2004. Collection, identification and characterization of Colletotrichum
spp. Infecting Strawberry (Fragaria x ananassa Duch) in Benguet. Unpublished
undergaraduate thesis. Benguet State University, La Trinidad, Benguet.Pp 1 - 9.
FATTAH, F. A. and J. M. WEBSTER. 1983. U`ltrastructural changes caused by
Fusarium oxysporum f. sp. lysofersici in Meloidogyne – induced giant cells in
Fusarium resistant and susceptible tomato cultivars. J. Nematol. 15 pp 128 – 135.
FERRAZ, L.C.C. and J.F. BROWN. 2002. An Introduction to nematodes: Plant
Pathology. Pen soft Publisher. Acad. G. Bonchew Str. B16, 1115 Sofia Bulgaria.
Pp.l45 – 50.
FLORES, M.F. 2007. Effect of Lesion Nematode (Pratylenchus penetrans filipjev and
Schuurmans Stekhoven) on the growth and yield of six strawberry cultivars
(Fragaria x ananassa Duch). BS Thesis, BSU, La Trinidad, Benguet. Pp 1-2.
HARRDEC, 1996. Benguet Strawberry Techno guide. Highland Agriculture and
Resources Resaech and Development Consortium. Benguet State University, La
Trinidad, Benguet. Pp 1- 18.
MAI, W. F. and G. S. ABAWI. 1987. Interactions among root – knot nematodes and
Fusarium wilt fungi on host plants. Annual Review of Phytopathology 25, 317 –
338.
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
23
MILNE, D. L. 1972. Nematodes of tobacco, pp 159 – 186. in : economic nematology, ed.
J. M. Webster, Academic Press, London. 563 pp.
NOLING, J.W. 1995. Nematodes and their Management Cooperative. Extension Service
Institute of Food and Agricultural Sciences, University of Florida. Pp 23- 26.
PITCHER, R. S. 1974. The reduction of resitance of tomato to Fusarium wilt by
Meloidogyne javanica ( Nematoda). Ms Thesis. Simon Fraser Lenio, Vancouver.
75 pp.
POWELL, M. and HANDLEY (eds). 1991. Bramble Production Guide. Northeast
Regional Agricultural Engineering Service. Pub. No. NRAES- 35 Pp 189.
SASSER, J. N. 1972. nematology disease of cotton, pp 187 – 214. in: economic
Nematology, ed. J. M. Webster, Academic Press, London. 563 pp.
SHURTLEFF, M.C. and AVERRE, C. W.2000. Diagnosing plant diseases caused by
nematodes. APS Press, St. Paul Minnesota.Pp 60- 74.
STARR, J. L., M. J. JEGGER, R. D. MARTIN, and K. SCHILLING. 1989. Effects of
Meloidogyne incognita and Fusarium oxysporum f. sp. vasinfectum on plant
mortality and yield of cotton. Phytopathology 79: 640 -646.
TARR, S.A.J. 1972. Principles of Plant Pathology. London. Mc Millan Press. Pp. 25 –
30.
VEGA, J. M., J. I. PAEZ, J. M. LOPEZ – ARAWDA, J. J. MEDINA, L. MIRANDA
AND F. MONTES. 2002. Nematodes in strawberries in Southern Spain.
Nematology International Journal of Fundamental and Applied Nematological
Research. 4 (2): 303.
VILLANUEVA, L. M., D. DEWAELE, N. B. PEDROCHE and C. D. DUGUI-ES. 2007.
Sustainable Management of Plant Parasitic Nematode Associated with Semi-
temperate Vegetable in the Cordillera.Progress Report. Benguet State University.
Pp. 20 – 21.
WEBSTER, J. M. 1985. interaction of Meloidogyne with fungi on plants. Pp. 183 – 192.
in: An advanced Treatise on Meloidogyne vol. 1 Analogy and control, eds. J. n.
Sasser and c. c. carter. Fort Carolina State University Graphics. 422 pp.
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
APPENDICES
Table 1. Effect of root- knot nematode (Meloidogyne incognita) and Fusarium sp. on the disease
severity
TREATMENT
REPLICATION
I
II
III
TOTAL
MEAN
T1 3
4
4
11
3.66
T2 18
4
11
33
11
T3 Fusarium
sp. 31 27 25 83
27.66
T4 RRN+Fusarium sp.
28
25
26
79
26.33
ANALYSIS OF VARIANCE
SOURCE DF
SS
MS F Tabular
Value
0.05 0
Replication
3
0.024
0.012
2.0308
Treatment
3
0.785
0.262
44.6400
4.76 9
Error
6
0.035
0.006
Total 11
0.844
ns- not significant
**- Highly significant
Coefficient of Variation: 12.14%
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
25
Table 2. Effect of root- knot nematode (Meloidogyne incognita) and Fusarium sp. on fresh root
weight
TREATMENT
REPLICATION .
I
II
III
TOTAL
MEAN
T1 Control 7.8
8.24
12.31
28.35
9.45
T2 RKN
10.84
13.04
13.5
37.38
12.46
T3 Fusarium sp.
7.55
6.78
9.16
23.49
7.83
T4 RRN+Fusarium sp.
7.55
6.78
9.16
23.49
7.83
ANALYSIS OF VARIANCE
Source
DF
SS
MS
F
Tabular
Value
0.05 0
Replication
2
0.020
0.010
1.7857
Treatment
3
0.078
0.026
4.6266
4.76 9
Error
6
0.034
0.006
0.006
Total 11
0.131
ns - not significant
Coefficient of Variation: 14.37%
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
26
Table 3. Effect of root- knot nematode (Meloidogyne incognita) and Fusarium sp. on fresh top
weight
TREATMENT
REPLICATION .
I
II
III
TOTAL
MEAN
T1 Control
8.02
7.97
12.4
28.39
9.46
T2 RKN
6.09
15.55
4.69
26.33
8.77
T3 Fusarium sp.
1.52
2.7
9.46
13.68
4.56
T4 RRN+Fusarium sp.
4.02
6.57
8.08
18.67
6.22
ANALYSIS OF VARIANCE
Source
DF
DD
MS
F
Tabular
Value
0.05 0
Replication
2
0.321
0.160
2.3192
Treatment
3
0.096
0.032
0.4649
4.76 9
Error
6
0.415
0.069
Total 11
0.832
ns - not significant
Coefficient of Variation: 56.76%
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
27
Table 4. Effect of root- knot nematode (Meloidogyne incognita) and Fusarium sp. on the
number of J2 in 3 g of root
TREATMENT
REPLICATION .
I
II
III
TOTAL
MEAN
T1 Control 0
0
0
0
0
T2 RKN
875
995
935
2805
935
T3 Fusarium sp.
0
0
0
0
0
T4 RRN+Fusarium sp.
13
0
0
13
433
ANALYSIS OF VARIANCE
Source
DF
SS
MS
F
Tabular
Value
0.05 0
Replication
2
0.045
0.022
0.8144
Treatment
3
17.605
5.868
4.76 9
Error
6
0.165
0.028
Total 11
2.466
213.0443
ns- not significant
**- Highly significant
Coefficient of Variation: 16.92%
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
28
Table 5. Effect of root- knot nematode (Meloidogyne incognita) and Fusarium sp. on the number
of J3-J4 in 3 g of root
TREATMENT
REPLICATION .
I
II
III
TOTAL
MEAN
T1 Control 0
0
0
0
0
T2 RKN
508
643
575.5
1726.5
575.5
T3 Fusarium sp.
0
0
0
0
0
T4 RRN+Fusarium sp.
13
0
0
13
4.33
ANALYSIS OF VARIANCE
Source
DF
SS
MS
F
Tabular
Value
0.05 0
Replication
2
0.275
0.137
1.9643
Treatment
3
0.739
0.246
3.5222
4.76 9
Error
6
0.420
0.070
Total 11
1.434
ns- not significant
**- Highly significant
Coefficient of Variation: 43.27%
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
29
Table 6. Effect of root- knot nematode (Meloidogyne incognita) and Fusarium sp. on the total
number of nematode in 3 g of root
TREATMENT
REPLICATION .
I
II
III
TOTAL
MEAN
T1 Control 0
0
0
0
0
T2
RKN
1383 1638 1510 4531 1510.3
T3 Fusarium sp.
0
0
0
0
0
T4 RRN+Fusarium sp.
29
13
0
42
14
ANALYSIS OF VARIANCE
Source
DF
SS
MS
F
Tabular
Value
0.05 0
Replication
2
0.447
0.223
1.9208
Treatment
3
0.378
0.459
3.9528
4.76 9
Error
6
0.697
0.116
Total 11
2.522
ns- not significant
**- Highly significant
Coefficient of Variation: 21.25%
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
30
Table 7. Effect of root- knot nematode (Meloidogyne incognita) and Fusarium sp. on the total
number of nematode in 200 g of soil
TREATMENT
REPLICATION .
I
II
III
TOTAL
MEAN
T1 Control 0
0
0
0
0
T2 RKN
8
8
8
24
8
T3 Fusarium sp.
0
0
0
0
0
T4 RRN+Fusarium sp.
5
10
7
22
733
ANALYSIS OF VARIANCE
Source
DF
SS
MS
F
Tabular
Value
0.05 0
Replication
2
0.023
0.012
1.2396
Treatment
3
0.637
0.212
22.4564
4.76 9
Error
6
0.057
0.009
Total 11
0.717
ns- not significant
**- Highly significant
Coefficient of Variation: 42.28%
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
WAKAT, VERON A. APRIL 2008. Influence of Root-Knot Nematode
(Meloidogyne incognita) on the severity of Fusarium wilt on Strawberry ( Fragaria x
ananassa Duch). Benguet State University, La Trinidad, Benguet.
Adviser: Luciana M. Villanueva, Ph.D.
ABSTRACT
The effect of root-knot nematode, Meloidogyne incognita on the severity of
Fusarium wilt of strawberry was evaluated under greenhouse conditions. Inoculation of
strawberry cultivar Sweet Charlie with 1,000 second stage juvenile of root-knot nematode
in combination with Fusarium sp. resulted in greater incidence and severity of Fusarium
wilt. However, this was not significantly different from plants inoculated with the fungus
alone. Fresh root weight was significantly reduced when plants were inoculated with
fungus alone and the combination of nematode and fungus. However, no significant
effect was noted on the fresh top weight.
A significant number of second, third and forth stage juveniles of root-knot
nematode was recovered from the roots of plants inoculated with nematode alone but
they did not develop into adult females. On the other hand, significantly less number of
J2, J3 and J4 was noted in the roots of plants inoculated with the combination of
nematode and the fungus.
The results imply that strawberry cultivar Sweet Charlie is not a suitable host of
M. incognita. Thus, the expected increase in the severity of Fusarium wilt due to
inoculation of nematode plus fungus was not observed in the present investigation despite
the susceptibility of the strawberry cultivar to the fungal pathogen.
ii
TABLE OF CONTENTS
Page
Bibliography. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
Abstract. . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
Table of Contents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
REVIEW OF LITERATURE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
MATERIALS AND METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
A. Root- knot Nematode( Meloidogyne incognita) . . . . . . . . . . . . 7
Source of nematode Inocula. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Standardization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Inoculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
B.Fusarium wilt. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Isolation of the Organism. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Standardization of the Inoculum. . . . . . . . . . . . . . . . . . . . . . . . . . 8
Inoculation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
RESULTS AND DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Disease Severity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Fresh Root Weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Fresh Top Weight. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Number of J2 in 3 g of Root . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Number of J3-J4 in 3 g of Root . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Total Number of Nematode in the Soil . . . . . . . . . . . . . . . . . . . . . . . . . 15
iii
SUMMARY, CONCLUSION AND RECOMMENDATION . . . . . . . . . . . 20
LITERATURECITED. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
APPENDICES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
iv
INTRODUCTION
In Baguio and Benguet, particularly in La Trinidad strawberry, (Fragaria x
ananassa Duch) production is one of the sources of farmers’ income. It is grown for its
edible red fruits which are either eaten as fresh and flavoring purposes. It is highly demanded
by tourists, processing factories like Magnolia, Nestle as well as local consumers (Flores,
2007). It contains ellagic acid, which is a potent antioxidant. Strawberries are highly
perishable, and vitamin C is present on the berries (Esiong, 2004).
Several strawberry varieties were earlier introduced in the highland; which includes
Tioga, Solana, Royal Gem, Mission bells and Fukuba. These varieties are no longer planted
in the locality. The most widely grown variety today is Sweet Charlie.
Recent survey showed the presence of Fusarium spp. in strawberry growing areas
in Baguio and Benguet. This fungus usually enters its host through feeder roots, and then it
multiplies and colonizes the vascular system. Infection may occur at any time during the life
of the plant. The disease is more severe when air and soil temperature are 78˚ to 90˚ F and is
more likely to occur in poorly drained soil (Tarr, 1972).
Meloidogyne has the greatest capability in predisposing plants to attack by
Fusarium spp. Interactions between Meloidogyne spp. and Fusarium oxysporum have been
reported in many crops (Mai and Abawi, 1987). Most papers on this interaction reported the
use of inoculum at either specified concentrations or densities that were unnaturally high.
Roots commonly were wounded, either by cutting, transplanting, or making inoculation holes
in the soil. Studies of the effects of different inoculum densities have demonstrated an
increased in susceptibility to Fusarium wilt at moderate or high levels of Meloidogyne spp.
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
2
and moderate levels of F. oxysporum in watermelon (Summer and Johnson, 1973) and cotton
(Starr and Garbey et. al, 1989).
Objectives of the Study
1. To determine the influence of root-knot nematode (Meloidogyne incognita) on
the severity of Fusarium wilt in strawberry, and
2. To determine the effect of Fusarium sp. on the reproduction/ population of M.
incognita.
Time and place of the study
The study was conducted at the BIOCON laboratory and greenhouse of
Horticultural Research and Training Institute, (HORTI) Benguet State University, La
Trinidad, Benguet.
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
REVIEW OF LITERATURE
The Host Plant
Strawberry cultivar Sweet Charlie is from the University of Florida (UF). It is
resistant to anthracnose fruit rot. The fruit has distinctly sweet flavor due to high sugar/
acid ratio. Its external fruit color is orange red and internal color is orange streaked with
white. The fruit is generally less firm than the fruit of Oso Grande and have average size
of 17 g, which is similar to that of Selva but less than that of Oso Grande. Fruit has a
larger calyx compared to the fruit of other cultivars grown in Florida (Anonymous,
2002).
The Pathogen
Fusarium wilt. Fusarium wilt is a soil borne fungal disease that affects a wide
variety of herbaceous plants, causing wilting and death.
Fusarium is a large genus of filamentous fungi widely distributed in soil and in
association with plants. Most species are harmless saprobes and are relatively abundant
members of the soil microbial community.
Disease cycle
The
Fusarium fungus survives and may actually increase in a number of soil
types for many years, independent of any host plants. This ability to survive eliminated
any normal rotation program on general sanitation as an effective control measure. The
appearance and severity of the disease are increased when air and soil temperature
average at this rise at point. The fungus grows most rapidly and the disease is most severe
at temperature 80 to 85˚F (26˚ to 29ْ˚ C). The Fusarium wilt fungus invades the plant
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
4
through the young rootlets or wounds in the older roots at transplanting time or later. The
fungus moves directly to the water- conducting tissues (xylem) and they progresses up
the stem into the leaves. The fungus colonizes the xylem tissues and does not invade
other tissues until part or the entire plant dies. The fungus produces its spore both inside
and outside the affected stems.
Life Cycle
According to Agrios (1988), Fusarium produces one to two- celled thick- walled
clamydospores that can withstand drought and low temperature. The fungus thrives on
dead plant tissues and can over winter as mycelium or spores on infected tissues or seeds.
The spores are early spread by air, contaminated equipment and water
Species
of
Fusarium produces two types of conidia that are termed macroconidia
and microconidia (Alexopolus, 1996).
Persistence and transmission
Fusarium
wilt can persist in most soils indefinitely because of its ability to
colonize the roots of a number of weeds and to produce resistant spore structure.
Symptoms
Symptoms of black root rot usually begin in the first fruiting year. The injury is
most noticeable in low or compacted soil of a field where drainage is poor. Strawberry
plants with black root rot show a general lack of vigor with poor runner growth and small
berries. Plants may collapse when water demand is high such as during spring growth,
during or after fruiting, or during drought stress (Ellis et al., 2005).
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
5
Site Selection
To reduce infection of Fusarium sp., future planting site should be selected at
least one year before planting. Soil drainage should be good. Avoid low- lying areas that
have a tendency to be poorly drained (Pritts et al., 1991).
Control
Crop rotation is a great tool for controlling the disease as well, however, it is
difficult to control if the space is limited because the spore may persist for as long as six
years in the soil. In addition, the planting of host crops like eggplant, peppers, potatoes,
strawberries and raspberries may not be avoided.Plant only certified, disease free
transplants in fertile, well- drained soil .
Meloidogyne incognita Root- knot nematodes represent a relatively small but
economically important group of obligate plant pathogens (Agrios, 1997). They are
endoparasite with an interesting life cycle (Akthmar and Malik (N.D.)). They have
evolved very specialized and established complex feeding relationship with their host
plants. Juveniles hatch from egg after already having molted once. These second stage
juveniles travel though the soil until they find plant tissue where they can penetrate and
feed on, usually on tender root tip (Ferraz and Brown, 2002).
Symptoms
Plants infected with root-knot nematode exhibit leaf chlorosis, stunting and less
blossom. Galling is also observed and the degree depends on the population of the
nematode in the soil.
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
6
Survival of Nematodes
Nematode population is influenced by many factors. Soil moisture is one of the
major factor affecting the nematode population, especially when rapid and extreme
changes occur in the soil environment (HARRDEC, 1996). Since nematodes are aquatic
animals, they require film of water coating soil particle for motility and survival (Agrios,
1997).
Control
Solarization can effectively suppress most species of nematode. This is an non-
chemical technique in which transparent polyethylene film is laid over raised beds for 2-
6 period to heat non- cropped soil to temperature lethal to nematodes and other soil borne
pathogens (Noling,1995).
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
MATERIALS AND METHODS
The study was conducted at the BIOCON Laboratory and greenhouse of
Horticultural Research and training Institute, Benguet State University, La Trinidad,
Benguet. There were four treatments, which were replicated three times. Rice hull and
sand were mixed and heat- sterilized prior to inoculation.
A. Root-Knot Nematode (Meloidogyne incognita)
Source of Nematode Inocula
Galled roots were collected from single egg mass culture and washed with tap
water to remove the adhering soil particles. These galled roots containing egg masses of
M. incognita were chopped into 1- 2 cm pieces and placed in 250 ml flasks. The eggs
were allowed to disperse by dissolving the gelatinous matrix using 1% NaOCL solution
(commercial bleach) in flasks which were vigorous by shaken (Shurtleff and Averre,
2000).
Standardization
Nematodes in water suspension were standardized by determining the number of
eggs in a known volume. The suspension was agitated by stirring and blowing of pipette
to make air bubbles while an aliquot was being withdrawn to ensure the even distribution
of nematodes. When the tip of the pipette is midway between the top and the bottom of
the liquid, an aliquot was immediately drawn and released into a counting dish. The
number of eggs in a 1 ml aliquot was counted under a stereomicroscope and multiplied
by the total volume of the suspension.
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
8
Inoculation
One thousand (1,000) eggs were used for inoculation per plant (Villanueva et. al,
2007).
B. Fusarium wilt.
Isolation of the Organism
Infected strawberries were collected from the field and washed thoroughly to
remove the adhering soil particles. The roots were cut measuring 1 cm and surface-
sterilized with 1% NaOCL, blot dry and washed three times with sterile distilled water.
Sections of infected roots were placed in previously plated kidney bean agar.
Standardization of the Inoculum
Suspension containing conidia was prepared and spore concentration was
estimated using a haemacytometer. One ml of conidial suspension was sucked using a
micropipette and deposited on the ridge of the hemacytometer. After the suspension had
flown automatically to the counting chamber, conidia counting was done in five squares
of the nine squares labeled A which contains 16 small squares. Standardization was done
three times. The average count of the five squares per trial was multiplied with 50,000 to
obtain the total spore/ ml.
Inoculation
One week after the inoculation of the root- knot nematode (M. incognita), the
plants were inoculated with Fusarium sp. using the inoculum level of 1x 106 spore/ ml.
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
9
The different treatments were the following:
T1- Uninoculated
T2- Root-knot nematode (M. incognita) alone
T3- Fusarium sp. alone
T4- Root-knot nematode (M. incognita) + Fusarium sp.
Data Gathered
1. Disease severity. plants were assessed for Fusarium wilt severity using the
rating scale below:
Rating Description
1 normal; no infection
2 .5- 5 cm discoloration
3 6- 10 cm discoloration
4 11- 20 cm discoloration
5 31- 40 cm discoloration
6 41- 60 cm discoloration
7 61- 80 cm discoloration
8 81- 100 cm discoloration
2. Top weight (g). This refers to the weight of the upper portion of the plant after
harvest.
3. Root weight (g). This refers to the weight of the root after harvest.
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
10
4. Number of nematodes in 3 g of root. Population counts of nematodes in feeding
position were made from 3 g roots per treatment. Roots were stained in acid fuchsin
glycerol to facilitate counting.
5. Number of nematodes in 200 g of soil (g). To determine whether the population
of root knot decreased or increased, 200 g of soil samples were obtained from each pot
and processed using the modified Baermann-tray technique. The nematodes were
collected separately in 150-ml capacity Erlenmeyer flasks. The suspensions were allowed
to stand at least 3 hours at room temperature and the excess water in the flasks was
reduced to 50 ml by suction using a pipette. The nematodes were transferred to 50 ml
capacity test tubes and were again allowed to stand at least 1 hour for nematodes to settle
at the bottom. The nematodes were counted under a stereoscopic microscope.
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
RESULTS AND DISCUSSION
Disease Severity
Inoculation
of
Fusarium sp. and Meloidogyne incognita on strawberry cultivar
Sweet Charlie resulted in wilting and sudden death of the plant (Fig. 1). However, it did
not significantly differ with plants inoculated with Fusarium alone. Plants inoculated
with nematode also showed vascular discoloration but significantly lower than those
inoculated with the fungus and the combination of fungus and nematode. On the other
hand, the uninoculated plants did not show vascular discoloration and wilting typical of
Fusarium wilt infection. This was significantly different from the other treatments.
Fresh Root Weight
Plants inoculated with Fusarium wilt alone resulted in significantly lower fresh
top weight (Figure 2). Although not significantly different from plants inoculated with
the combination of the fungus and nematode and uninoculated control, those inoculated
with root-knot nematode alone has the highest fresh root weight. Nevertheless, this was
significantly higher than those plants inoculated with Fusarium sp. alone.
Fresh Top Weight
Inoculation
of
root-knot
nematode alone, combination of nematodes and Fusarium
sp. and fungus alone did not significantly affect the fresh top weight of strawberry (Fig.
3).
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
12
8
a
7
a
r
i
t
y
6
5
e
ve
S
4
b
se
3
2
a
i
sea
D
1
0
Control
root-knot
Fusarium
Root-knot
nematode
sp.alone
nematode
alone
+Fusarium
sp.
Treatment
Fig. 1. Effect of root-knot nematode (M. incognita) and Fusarium sp. on disease severity.
3.5
a
3
a
2.5
b
ab
2
e
i
ght
w
1.5
oot
R
1
0.5
0
Control
root-knot
Fusarium
Root-knot
nematode alone
sp.alone
nematode
+Fusarium sp.
Treatment
Fig. 2. Effect of root-knot nematode (M. incognita) and Fusarium sp. onweight.
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
13
2.5
a
a
2
a
g)
(
1.5
a
e
i
ght
1
Top W
0.5
0
Control
root-knot
Fusarium
Root-knot
nematode alone
sp.alone
nematode
+Fusarium sp.
Treatment
Fig. 3. Effect of root-knot nematode (M. incognita) and Fusarium sp. on fresh top weight
t
o
180
o
a
160
f
R
o
140
g
120
3
100
2
in
80
f
J
60
40
e
r
o
b
20
c
c
b
m
u
0
N
Control
root-knot
Fusarium
Root-knot
nematode alone
sp.alone
nematode
+Fusarium sp.
Treatment
Fig. 4. Effect of Effect of root-knot nematode (M. incognita) and Fusarium sp. on the
number of J2 in 3 g of roots
Number of J2 in the Root
Figure 4 shows the effect of the different treatments on the number of second
stage juveniles in the root of strawberry. Apparently, the highest population of J2 was
noted in plants inoculated with root-knot nematode alone. This was significantly different
from those inoculated with the combination of the nematode and the fungus. No
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
14
nematode was recorded from the uninoculated plants and those inoculated with Fusarium
sp. alone.
Number of J3 and J4 in the Root
The effect of the different treatments on the number of third and fourth stage
juveniles in 3 g root is shown in Figure 5. The highest nematode count was noted in
plants inoculated with root-knot nematode alone. This was significantly different from
plants inoculated with the combination of nematode and the fungus. There was no
nematode recovered from the control, plants and those inoculated with Fusarium sp.
alone.
The absence of adult female nematode in the roots indicates that the nematode
failed to develop up to maturity. According to Powell et. al (1960) fungal colonization of
giant cells(the source of food for the nematode) and xylem is common in fungus-root
knot interactions. The fact that the structure of the giant cell changes prior to fungal entry
implies that translocatable fungal secretions rather than the penetrating hyphae initially
modify and eventually kill the giant cells (Fattah and Webster, 1983). In addition to this
fungus-induced/produced factor in the Meloidogyne-Fusarium disease complex on
tomato, the developing nematode produces a factor or induces the plant to produce such a
factor that is transmitted upward through the plant and breaks the fungal resistance (i.e.
predisposes) of the host to Fusarium. The fungus develops and its secretions cause a
progressible necrosis of the giant cell which, in turn, causes the nematode to stave to
death.
Generally, the increase in the severity of Fusarium wilt in the strawberry due to
M. incognita was not observed in the present study. This could be due to the following
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
15
reasons. First, strawberry is not a suitable host of M. incognita and second , Fusarium sp.
has an adverse effect on the development and reproduction of the nematode.
Previous reports have shown that strawberry is not a suitable host of M. incognita.
However, in Huelva, Spain M. incognita was one of the root knot nematodes recover
from strawberry samples aside from M.hapla,M.arenaria and Meloidogyne sp.(Vega et.
al 2002). Early observations of nematode- fungal interaction suggested that they were
due to the nematode providing a ready means of entry into the host for the fungus.
Undoubtedly, this occurs when root- browsing nematode cause superficial root injury and
so enhance fungal asses and secondary pathogenicity of the roots (Webster, 1985).
The
Meloidogyne- Fusarium interaction has been extensively studied because of
its significance on major world crops, such as cotton (Sasser, 1972) and tobacco (Milne,
1972). The extent of the disease interaction is greatly influenced by range of factors. For
instance, there is more extensive Fusarium colonization of the plant tissues as the number
of developing Meloidogyne increases. Moreover, symptom expression, as a manifestation
of disease interaction is greater in “young” than in “old” plants (Pitcher, 1974).
Total Number of Nematodes in the soil
Figure 6 shows the number of nematodes recovered from the soil. No significant
difference was noted between those inoculated with nematode alone and the combination
of root-knot nematode and Fusarium sp. As expected, no nematodes were obtained from
the inoculated pots and those applied with Fusarium sp. alone.
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
16
t
o
o
120
a
f
r
o
100
g
3
80
60
3
-
J
4
in
f
J
40
e
r
o
20
b
b
b
b
m
0
u
N
Control
root-knot
Fusarium
Root-knot
nematode alone
sp.alone
nematode
+Fusarium sp.
Treatment
Fig. 5. Number of third and fourth stage juveniles in 3 g of roots as affected by the
different
treatments
a
1600
g of
1400
n 3
i
1200
1000
a
t
ode
m
800
ne
r
oot
600
r
of
400
be
200
c
c
b
0
a
l
num
Control
Root-knot
Fusarium
Root-knot
Tot
nematode
sp.alone
nematode +
alone
Fusarium sp.
treatment
Fig. 6. Total number of nematodes in 3 g roots as affected by the different treatments.
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
17
f
2.5
o
0
0
g
2
2
e
in
1.5
d
l
a
t
o
1
Soi
e
m
f
N
0.5
e
r
o
b
0
m
Control
root-knot
Fusarium
Root-knot
u
N
nematode
sp.alone
nematode
alone
+Fusarium sp.
Treatment
Fig.7. Number of nematodes in the soil
Fig. 8. Second stage juveniles (J2) of M. incognita inside the roots of strawberry. Note the
absence of mature females.
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
18
Fig.9. Pure culture of Fusarium sp. isolated from infected strawberry.
Fig.10. Macroconidia and microconidia of Fusarium sp.
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
19
A
B
C
D
Fig.11. Root systems of strawberry cultivar Sweet Charlie A – Uninoculated control, B –
inoculated with M. incognita alone; C – Inoculated with Fusarium sp. alone and
D – Inoculated with Fusarium sp. + M. incognita
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
SUMMARY, CONCLUSION AND RECOMMENDATION
Summary
A greenhouse experiment was conducted to determine the influence of root-knot
nematode (Meloidogyne incognita) on the severity of Fusarium wilt in strawberry
cultivar Sweet Charlie. Inoculation of 1,000 second stage juveniles (J2) of M. incognita
did not significantly enhance the incidence and severity of Fusarium wilt of strawberry.
Inoculation of root-knot nematode alone and the combination of root-knot
nematode and Fusarium sp. resulted in significant reduction in fresh root weight but not
in fresh top weight.
A significant number of second, third and fourth stage juveniles of root-knot
nematode was recovered from the roots of plants inoculated with nematode alone but
they did not develop into adult females. On the other hand, significantly less number of
J2, J3 and J4 was noted in the roots of plants inoculated with the combination of root-
knot nematode and Fusarium sp. indicating the adverse effect of the fungus on the
growth and development of the nematode.
Conclusion
Based on the results obtained, strawberry cultivar Sweet Charlie is not a suitable
host to root-knot nematode. Because of the above reason, the nematode was not able to
enhance the incidence and severity of Fusarium wilt despite the susceptibility of
strawberry cultivar Sweet Charlie to Fusarium sp.
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
21
Recommendations
Further studies are therefore necessary using another species of Meloidogyne
(preferably M. hapla) to fully evaluate the influence of the above nematode on the
severity of Fusarium wilt in strawberry. Studies on the effect of varying nematode
population densities and inoculation methods which minimize wounding are also
recommended.
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
LITERATURE CITED
AGRIOS, G.N. 1988. Plant Pathology. 3rd edition. San Diego, California: Academic
Press. Pp. 21 – 26.
AGRIOS, G.N. 1997.Plant Pathology. 4th edition. San Diego, California. Pp565-567.
AKHMAR, M. and A. MALIK.N.D. Role of Organism, Soil Amendment and soil
organism in biological control of plant parasitic nematode Journal 23: 153.
ALEXOPOULOS,C.J. 1996. Introductory Mycology. 4th edition. New York: John Wiley
and Sons, Inc. Pp.244.
ANONYMUOS, 2002. Lansen Canyon Nursery Commercial Strawberry Growers.
Retrieved April 28, 2007 from http://www.lansencanyoonursery. /comm.
Varieties
ELLIS, M.A. 1995. Organic small fruit disease management guideline department of
Plant Pathology at the Ohio State University. Pp. 30 – 35.
ESIONG, M.S. 2004. Collection, identification and characterization of Colletotrichum
spp. Infecting Strawberry (Fragaria x ananassa Duch) in Benguet. Unpublished
undergaraduate thesis. Benguet State University, La Trinidad, Benguet.Pp 1 - 9.
FATTAH, F. A. and J. M. WEBSTER. 1983. U`ltrastructural changes caused by
Fusarium oxysporum f. sp. lysofersici in Meloidogyne – induced giant cells in
Fusarium resistant and susceptible tomato cultivars. J. Nematol. 15 pp 128 – 135.
FERRAZ, L.C.C. and J.F. BROWN. 2002. An Introduction to nematodes: Plant
Pathology. Pen soft Publisher. Acad. G. Bonchew Str. B16, 1115 Sofia Bulgaria.
Pp.l45 – 50.
FLORES, M.F. 2007. Effect of Lesion Nematode (Pratylenchus penetrans filipjev and
Schuurmans Stekhoven) on the growth and yield of six strawberry cultivars
(Fragaria x ananassa Duch). BS Thesis, BSU, La Trinidad, Benguet. Pp 1-2.
HARRDEC, 1996. Benguet Strawberry Techno guide. Highland Agriculture and
Resources Resaech and Development Consortium. Benguet State University, La
Trinidad, Benguet. Pp 1- 18.
MAI, W. F. and G. S. ABAWI. 1987. Interactions among root – knot nematodes and
Fusarium wilt fungi on host plants. Annual Review of Phytopathology 25, 317 –
338.
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
23
MILNE, D. L. 1972. Nematodes of tobacco, pp 159 – 186. in : economic nematology, ed.
J. M. Webster, Academic Press, London. 563 pp.
NOLING, J.W. 1995. Nematodes and their Management Cooperative. Extension Service
Institute of Food and Agricultural Sciences, University of Florida. Pp 23- 26.
PITCHER, R. S. 1974. The reduction of resitance of tomato to Fusarium wilt by
Meloidogyne javanica ( Nematoda). Ms Thesis. Simon Fraser Lenio, Vancouver.
75 pp.
POWELL, M. and HANDLEY (eds). 1991. Bramble Production Guide. Northeast
Regional Agricultural Engineering Service. Pub. No. NRAES- 35 Pp 189.
SASSER, J. N. 1972. nematology disease of cotton, pp 187 – 214. in: economic
Nematology, ed. J. M. Webster, Academic Press, London. 563 pp.
SHURTLEFF, M.C. and AVERRE, C. W.2000. Diagnosing plant diseases caused by
nematodes. APS Press, St. Paul Minnesota.Pp 60- 74.
STARR, J. L., M. J. JEGGER, R. D. MARTIN, and K. SCHILLING. 1989. Effects of
Meloidogyne incognita and Fusarium oxysporum f. sp. vasinfectum on plant
mortality and yield of cotton. Phytopathology 79: 640 -646.
TARR, S.A.J. 1972. Principles of Plant Pathology. London. Mc Millan Press. Pp. 25 –
30.
VEGA, J. M., J. I. PAEZ, J. M. LOPEZ – ARAWDA, J. J. MEDINA, L. MIRANDA
AND F. MONTES. 2002. Nematodes in strawberries in Southern Spain.
Nematology International Journal of Fundamental and Applied Nematological
Research. 4 (2): 303.
VILLANUEVA, L. M., D. DEWAELE, N. B. PEDROCHE and C. D. DUGUI-ES. 2007.
Sustainable Management of Plant Parasitic Nematode Associated with Semi-
temperate Vegetable in the Cordillera.Progress Report. Benguet State University.
Pp. 20 – 21.
WEBSTER, J. M. 1985. interaction of Meloidogyne with fungi on plants. Pp. 183 – 192.
in: An advanced Treatise on Meloidogyne vol. 1 Analogy and control, eds. J. n.
Sasser and c. c. carter. Fort Carolina State University Graphics. 422 pp.
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
APPENDICES
Table 1. Effect of root- knot nematode (Meloidogyne incognita) and Fusarium sp. on the disease
severity
TREATMENT
REPLICATION
I
II
III
TOTAL
MEAN
T1 3
4
4
11
3.66
T2 18
4
11
33
11
T3 Fusarium
sp. 31 27 25 83
27.66
T4 RRN+Fusarium sp.
28
25
26
79
26.33
ANALYSIS OF VARIANCE
SOURCE DF
SS
MS F Tabular
Value
0.05 0
Replication
3
0.024
0.012
2.0308
Treatment
3
0.785
0.262
44.6400
4.76 9
Error
6
0.035
0.006
Total 11
0.844
ns- not significant
**- Highly significant
Coefficient of Variation: 12.14%
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
25
Table 2. Effect of root- knot nematode (Meloidogyne incognita) and Fusarium sp. on fresh root
weight
TREATMENT
REPLICATION .
I
II
III
TOTAL
MEAN
T1 Control 7.8
8.24
12.31
28.35
9.45
T2 RKN
10.84
13.04
13.5
37.38
12.46
T3 Fusarium sp.
7.55
6.78
9.16
23.49
7.83
T4 RRN+Fusarium sp.
7.55
6.78
9.16
23.49
7.83
ANALYSIS OF VARIANCE
Source
DF
SS
MS
F
Tabular
Value
0.05 0
Replication
2
0.020
0.010
1.7857
Treatment
3
0.078
0.026
4.6266
4.76 9
Error
6
0.034
0.006
0.006
Total 11
0.131
ns - not significant
Coefficient of Variation: 14.37%
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
26
Table 3. Effect of root- knot nematode (Meloidogyne incognita) and Fusarium sp. on fresh top
weight
TREATMENT
REPLICATION .
I
II
III
TOTAL
MEAN
T1 Control
8.02
7.97
12.4
28.39
9.46
T2 RKN
6.09
15.55
4.69
26.33
8.77
T3 Fusarium sp.
1.52
2.7
9.46
13.68
4.56
T4 RRN+Fusarium sp.
4.02
6.57
8.08
18.67
6.22
ANALYSIS OF VARIANCE
Source
DF
DD
MS
F
Tabular
Value
0.05 0
Replication
2
0.321
0.160
2.3192
Treatment
3
0.096
0.032
0.4649
4.76 9
Error
6
0.415
0.069
Total 11
0.832
ns - not significant
Coefficient of Variation: 56.76%
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
27
Table 4. Effect of root- knot nematode (Meloidogyne incognita) and Fusarium sp. on the
number of J2 in 3 g of root
TREATMENT
REPLICATION .
I
II
III
TOTAL
MEAN
T1 Control 0
0
0
0
0
T2 RKN
875
995
935
2805
935
T3 Fusarium sp.
0
0
0
0
0
T4 RRN+Fusarium sp.
13
0
0
13
433
ANALYSIS OF VARIANCE
Source
DF
SS
MS
F
Tabular
Value
0.05 0
Replication
2
0.045
0.022
0.8144
Treatment
3
17.605
5.868
4.76 9
Error
6
0.165
0.028
Total 11
2.466
213.0443
ns- not significant
**- Highly significant
Coefficient of Variation: 16.92%
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
28
Table 5. Effect of root- knot nematode (Meloidogyne incognita) and Fusarium sp. on the number
of J3-J4 in 3 g of root
TREATMENT
REPLICATION .
I
II
III
TOTAL
MEAN
T1 Control 0
0
0
0
0
T2 RKN
508
643
575.5
1726.5
575.5
T3 Fusarium sp.
0
0
0
0
0
T4 RRN+Fusarium sp.
13
0
0
13
4.33
ANALYSIS OF VARIANCE
Source
DF
SS
MS
F
Tabular
Value
0.05 0
Replication
2
0.275
0.137
1.9643
Treatment
3
0.739
0.246
3.5222
4.76 9
Error
6
0.420
0.070
Total 11
1.434
ns- not significant
**- Highly significant
Coefficient of Variation: 43.27%
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
29
Table 6. Effect of root- knot nematode (Meloidogyne incognita) and Fusarium sp. on the total
number of nematode in 3 g of root
TREATMENT
REPLICATION .
I
II
III
TOTAL
MEAN
T1 Control 0
0
0
0
0
T2
RKN
1383 1638 1510 4531 1510.3
T3 Fusarium sp.
0
0
0
0
0
T4 RRN+Fusarium sp.
29
13
0
42
14
ANALYSIS OF VARIANCE
Source
DF
SS
MS
F
Tabular
Value
0.05 0
Replication
2
0.447
0.223
1.9208
Treatment
3
0.378
0.459
3.9528
4.76 9
Error
6
0.697
0.116
Total 11
2.522
ns- not significant
**- Highly significant
Coefficient of Variation: 21.25%
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
30
Table 7. Effect of root- knot nematode (Meloidogyne incognita) and Fusarium sp. on the total
number of nematode in 200 g of soil
TREATMENT
REPLICATION .
I
II
III
TOTAL
MEAN
T1 Control 0
0
0
0
0
T2 RKN
8
8
8
24
8
T3 Fusarium sp.
0
0
0
0
0
T4 RRN+Fusarium sp.
5
10
7
22
733
ANALYSIS OF VARIANCE
Source
DF
SS
MS
F
Tabular
Value
0.05 0
Replication
2
0.023
0.012
1.2396
Treatment
3
0.637
0.212
22.4564
4.76 9
Error
6
0.057
0.009
Total 11
0.717
ns- not significant
**- Highly significant
Coefficient of Variation: 42.28%
Influence of Root-Knot Nematode (Meloidogyne incognita) on the severity of
Fusarium wilt on Strawberry ( Fragaria x ananassa Duch)/ Veron A. Wakat. 2008
Document Outline
- Influence of Root-Knot Nematode
(Meloidogyne incognita) on the severity of Fusarium wilt on Strawberry ( Fragaria x
ananassa Duch)
- BIBLIOGRAPHY
- ABSTRACT
- TABLE OF CONTENTS
- INTRODUCTION
- Objectives of the Study
- Time and place of the study
- REVIEW OF LITERATURE
- The Host Plant
- The Pathogen
- Disease cycle
- Life Cycle
- Persistence and transmission
- MATERIALS AND METHODS
- Root-Knot Nematode (Meloidogyne incognita)
- Source of Nematode Inocula
- Standardization
- Inoculation
- Fusarium wilt.
- Isolation of the Organism
- Standardization of the Inoculum
- Inoculation
- Data Gathered
- Root-Knot Nematode (Meloidogyne incognita)
- RESULTS AND DISCUSSION
- Disease Severity
- Fresh Root Weight
- Fresh Top Weight
- Number of J2 in the Root
- Number of J3 and J4 in the Root
- Total Number of Nematodes in the soil
- SUMMARY, CONCLUSION AND RECOMMENDATION
- Summary
- Conclusion
- Recommendations
- LITERATURE CITED
- APPENDICES