BIBLIOGRAPHY FLORES, MARICAR F. APRIL...
BIBLIOGRAPHY
FLORES, MARICAR F. APRIL 2007. Effect of Lesion Nematode (Pratylenchus
penetrans Filipjev and Shuurmans Stekhoven) on the Growth and Yield of Six Strawberry
Cultivars (Fragaria x ananassa Duch). Benguet State University, La Trinidad, Benguet.
Adviser: Luciana M. Villanueva, Ph.D
ABSTRACT
The study was conducted at BIOCON Laboratory and Greenhouse, Horticultural
Research and Training Institute (HORTI), Benguet State University, La Trinidad,
Benguet to determine the effect of Pratylenchus penetrans on the growth and yield of six
strawberry cultivars.
Inoculation of 500 nematodes/pot did not significantly affect the fresh top weight,
fresh root weight, weight of fruits of Strawberry cultivars: Festival, Sweet Charlie,
Whitney, Winterdawn, Earlibrite and Camarosa. However, the number of fruits was
significantly reduced by the nematode inoculation in cultivar Sweet Charlie. The
nematode multiplication was significantly faster in cultivar Camarosa, however, it did not
significantly differ with Whitney and Wintedawn. The lowest nematode count in the
roots was obtained from Sweet Charlie, nevertheless, it was comparable to Earlibrite.
Based on the results it could be inferred that Sweet Charlie is more susceptible to
the P. Penetrans. On the other hand, Camarosa and Festival seem to be more tolerant to
nematodes.
TABLE OF CONTENTS
Page
Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
Table of Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
REVIEW OF LITERATURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
MATERIALS AND METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Source of Nematode Inoculum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Sterilization of Nematode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Inoculation of Root Lesion Nematode . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
RESULTS AND DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14
Fresh Top Weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Root Weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Number of Fruits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14
Fruit Weight. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Number of Nematode in Roots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Number of Nematode in Soil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
SUMMARY, CONCLUSION AND RECOMMENDATION . . . . . . . . . . . . . 25
LITERATURE CITED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
APPENDICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
ii
INTRODUCTION
The lesion nematode, Pratylenchus penetrans (Cobb) Filipjev and Schuurmans
Stekhoven has been found to infest and be pathogenic on the cultivated strawberry,
Fragaria x ananassa Duch (Potter and Dale, 1991). Several studies have observed that
lesion nematode reproduction varies on different cultivars. In West Virginia, Midway
strawberry appeared to be a better host than Surecrop (Adams and Hickman, 1970). In
Price Edward Island, significantly more Pratylenchus sp. were found in the cultivar
Cavalier than in Veestar, Redcoat, or Vibrant, and redcoat harbored more than Micmac
(Kimpinski, 1985). In the Pacific Northwest, no useful resistance was found in 14
cultivars, although the nematode multiplied more rapidly on some cultivars than on
others.
In the Philippines, P. penetrans was one of the plant parasitic nematodes found
associated with strawberry in Benguet and Baguio City (Villanueva, 1994). It occurred in
high population densities in all the fields surveyed and considered to be an active parasite
of strawberry in the area (Kiat-ong, 2005). Based on the above and below ground
symptoms, most of the strawberry cultivars grown are susceptible to the nematode.
Lesion nematodes reduce or inhibit root development by forming local lesions on young
roots, which may then rot with the entry of secondary fungi and bacteria. As a result of
the root damage, affected plants grow poorly, produce low yields, and may finally die
(Agrios, 1997).
The strawberry can both resist and tolerate the lesion nematode (Potter and Dale,
1994). Here we use the terminology of Boerma and Hussey (1992) to describe resistance
and tolerance. Resistance describes the ability of a host to suppress nematode
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
2
development and reproduction, and tolerance describe the sensitivity of a host to
parasitism or the amount of damage sustained.
The study was conducted at the BIOCON Laboratory and Greenhouse,
Horticultural Research and Training Institute, Benguet State University, La Trinidad,
Benguet from November, 2006 to March, 2007 to determine the effect of Pratylenchus
penetrans on growth and yield of six strawberry cultivars imported from California,
USA.
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
REVIEW OF LITERATURE
The strawberry, a perennial herb of the genus Fragaria of the Rose family is a
strange plant to many Filipinos particularly among the lowlanders. It is a semi-temperate
and photoperiodic crop. Its sweet juicy fruit is one of the highly priced commodities in
Baguio despite its abundance during the months of December to April. The crop is only
produced in Baguio-Benguet area of the Northern Philippines where the climate is unique
Recently, five strawberry cultivars were imported from California, USA. They are
Camarosa, Strawberry Festival, Earlibrite, Whitney and Winter Dawn. Camarosa, is an
early short day variety. The vigorous plants produce large fruit throughout the most
fruiting cycle. The interior color of Camarosa is a brilliant red and fruit colors uniformly.
Yield potential is high to excellent in University of California performance tests.
Strawberry Festival is also a short day cultivar. The fruits are mostly conic in shape. The
external color of mature fruit is deep red and glossy while the internal color is bright red.
The fruits of Strawberry Festival have very firm texture and excellent flavor. Strawberry
Festival has a fruiting pattern and yield similar to that of Camarosa. Sweet Charlie is an
early maturing sweet cultivar. The plant is medium in size making harvesting easy. Sweet
Charlie has also anthracnose tolerance. On the other hand, Earlibrite originated from
1993 cross between Rosalinda and FL 90-38. It is an early producer. Usually in
December it produces bright red fruits (Anonymous, 2002).
The lesion nematode, Pratylenchus penetrans (Cobb) Filipjev and Schuurmans
Stekhoven has been found to infest and be pathogenic on the cultivated strawberry,
Fragaria x ananassa Dutch (Potter and Dale, 1991). Several studies have observed that
lesion nematode reproduction varies on different cultivars. In West Virginia, Midway
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
4
strawberry appeared to be a better host than Surecrop (Adams and Hickman, 1970). In
Price Edward Island, significantly more Pratylenchus sp. were found in the cultivar
Cavalier than in Veestar, Redcoat, or Vibrant, and Redcoat harbored more nematodes
than Micmac (Kimpinski, 1985). In the Pacific Northwest, no useful resistance was
found in 14 cultivars, although the nematode multiplied more rapidly on some cultivars
than on others. For instance, they were able to reproduce readily on the cultivars
Olympus, Shuksan and Tyee, and less on Rainier (Vrain, 1985).
In Poland, Szczygiel (1981) evaluated 28 strawberry cultivars in pots for P.
penetrans susceptibility in terms of nematode numbers per gram of root and tolerance on
the bases of degree of root necrosis and reduction of plant growth. Also European and
North American cultivars were compared. While no strawberry was completely resistant
to P. penetrans, Guardian, Redchief and Sengana supported lower numbers of
nematodes, whereas Midway, Vesper and Grenadier supported large numbers. The latter
three cultivars also ranked among the highest in root necrosis, along with Cambridge
Favourite, whereas Guardian and Senga sengana were almost equally low on root
necrosis index. However, Midway and to a lesser extent, Vesper and Grenadier, did not
show reduced growth commensurate with the root necrosis index or large numbers of
nematodes. Szczygiel (1981) concluded that both root necrosis and reduced growth
should be evaluated to indicate nematode-induced damage to a cultivar.
The strawberry can both resist and tolerate the northern lesion nematode (Potter
and Dale, 1994). Here we use the terminology of Boerma and Hussey (1992) to describe
resistance and tolerance. Resistance describes the ability of a host to suppress nematode
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
5
development and reproduction, and tolerance describes the sensitivity of a host to
parasitism or the amount of damage sustained.
P. penetrans is a migratory endoparasite with all stages found in root cortex. Low
soil population can be associated with high root population. The nematodes feed mainly
on cortex and form cavities containing nests or colonies of nematode of all stages.
Discoloration of affected tissues is usually pronounced. Above ground symptoms of
attack include chlorosis and stunting (Bridge et al., 2002). High populations of lesion
nematodes cause areas of poor growth; plants are less vigorous, turn yellow and cease to
grow. Direct feeding often causes damage and, usually, only cortical tissues are affected.
Large nematode populations cause extensive lesion formation and cortex destruction of
unsuberized feeder roots (Brodie et al., 1981).
According to Anonymous (1999) the symptoms on infected roots are small, light
to dark brown lesions. The lesions tend to expand and to merge as the growing season
progresses, giving the roots a discolored appearance overall. Nematode feeding causes
cortical tissue disintegration and girdling, resulting in the sloughing off of the epidermis
and remaining cortex, root pruning, and the reduction in size of the root system. The roots
of severely infected plants maybe almost complete. Lesion formation results from an
interaction of plant glycosides with enzyme released by the nematode during feeding.
The chemicals are toxic to invaded and adjacent host cells. The degree of host parasite
interaction depends on the concentration and location of specific glycosides within the
root tissue on the concentration of enzymes released during feeding. The wounds produce
by the nematodes provide a means of entry for a wide variety of relatively and
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
6
nonspecific soil microorganisms, including root infecting pathogens that may also
contribute to lesion formation and may enhance the disease.
Pratylenchus penetrans, the main species pathogenic to strawberry, was also
found to carry spores of Gnomonia comari, the cause of leaf blotch (Kurppa and Vrain,
1989). These nematodes prefer coarse-textured, sandy soils. In temperate climates, they
over winter in roots or in soil as eggs, juveniles, or adults. During periods of drought,
they are quiescent and susceptible to drying if the soil is plowed and fallowed through hot
months. Where soil moisture is low some species can survive more than a year without a
host crop. Species of Pratylenchus are unusual in reproducing in larger numbers in
stressed plants. In all motile stages, this nematode can invade and leave roots, so there is
no infective stage. To estimate the size of population of Pratylenchus species, both roots
and soil should be sampled. Staining of roots suspected of harboring these nematodes or
extraction from such roots may be necessary to confirm their presence (Averre III et al.,
2000).
All species of Pratylenchus are readily distributed with the infected planting
material and, consequently, P. penetrans is widely distributed wherever strawberries are
grown. Several other species have been associated with strawberry but not all are
damaging. Damage by P. penetrans is greatest on light soils where a threshold of 50
nematodes 100g soil has been reported (Szczygiel, 1983).
Currently, nematode management considerations include crop rotation of less
susceptible crops and resistant varieties, cultural and tillage practices, use of transplants
and preplant nematicide treatments. These methods unlike other chemical methods tend
to reduce nematode population gradually overtime. Lesion nematodes can be best
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
7
controlled by overall or row treatment of the soil with the nematicides before the crop is
planted. Such treatments give good control of these nematodes, but they usually fail to
eradicate them completely. In hot and dry climates fairly good control of lesion nematode
can be achieved by summer fallow, which requires the nematode population by exposing
them to heat and drying by eliminating the host plants. Control through crop rotation is
rather unsuccessful because of the wide host range of the lesion nematodes. Several fungi
and bacteria that parasitize and kill lesion nematodes are known, but none are effective as
biological control agents under field conditions (Agrios, 1997).
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
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 from November 2006 to March 2007. There were two treatments replicated four
times with two sample plants per replicate. The treatments were arranged randomly in
greenhouse using the Randomized Complete Block Design (RCBD) involving factorial
arrangement. Six strawberry cultivars were used namely: Camarosa, Festival, Sweet
Charlie, Earlibrite, Whitney and Winter Dawn (Figure1).
Fig. 1. Experimental lay-out (RCBD)
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
9
The soil used in the experiment was obtained from the Benguet State University
Experimental Area located at Balili, La Trinidad, Benguet containing a mixture of rice
hull and sand together with the soil. It was heat-sterilized prior to use to get rid of other
soil-borne pathogens that will affect the development of nematodes.
Source of Nematode Inoculum
The nematodes were cultured in carrot discs. Healthy carrot roots were washed in
running water to remove the adhering soil particles and blot dried in tissue paper. It was
surfaced sterilized with 70% ethanol and peeled three times Carrots were cut into discs
and placed in sterile Petri dishes.
The infected roots were washed thoroughly with tap water and cut into small
pieces. These were macerated with a kitchen blender and passed through a 40-micrometer
sieve. The mixture of blended roots and nematodes from the sieve were placed overnight
in a Baerman funnel. This allowed the nematodes to pass through the sieve to the water
and the blended root tissue to remain. The residue in the sieve was rinsed with
tap water to eliminate bacteria, etc. The nematodes were collected from the sieve with
distilled water.
Sterilization of Nematodes
In order to establish a culture with the least possible contamination, it is important
to use clean nematode solution. The nematode suspension was transferred into a sterile
test tube containing sterile distilled water using a sterile pipette. About .6 ml of 600-ppm
streptomycin sulphate was added in 2 ml nematode suspension. The nematode suspension
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
10
was left overnight in sealed test tube; the streptomycin sulphate solution was removed
from above the nematodes and which was allowed to settle at the bottom of the test tube
for an hour. The water was removed and fresh sterile water is added. The process was
repeated three times.
Inoculation of the Lesion Nematode
Six strawberry cultivars were used namely: Camarosa, Festival, Sweet Charlie,
Earlibrite, Whitney and Winter Dawn. The inoculum was introduced in 4 holes near the
root zone and later covered again with soil. Uninoculated plants were provided to serve
as control.
The different treatments were the following:
Factor A: Inoculum Levels
T1-0
T2-500 nematodes/plant
Factor B: Variety
V1- Festival
V2- Sweet Charlie
V3- Whitney
V4- Winter dawn
V5- Earlibrite
V6- Camarosa
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
11
All the cultural management practices in strawberry production such as watering,
fertilization, removal of old leaves and control of pests except nematode was employed
uniformly in all the treatments to ensure good growth and yield of the plant.
Data Gathered
1. Top weight (g). This refers to the weight of the upper part of the plant after
harvest.
2. Root weight (g). This refers to the weight of the roots after harvest.
3. Number and weight of fruits/plant. This refers to number and weight of fruits
harvested per sample plant.
4. Number of nematodes in the roots. This was obtained by collecting one gram
of roots. The nematodes were extracted using a blender and nematodes were
collected using the blue sieve method (Figure 2).
5.
Number of nematodes in the soil. This was obtained by collecting 200 cc of
soil and processed using the Modified Tray Method (Figure 3).
The data were analyzed statistically using Analysis of Variance (ANOVA) and
treatment means were separated using the Duncan’s Multiple Range Test (DMRT).
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
12
(a) Blender (b) Blue sieve
Fig. 2. Extraction of nematode from the roots using (a) blender and (b) blue sieve
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
13
B
A
C
D
Fig. 3. M0dified tray method of isolating nematodes from soil placed in mayonnaise
bottle (A&B), collection opf nematode suspension (C&D)
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
RESULTS AND DISCUSSIONS
Fresh Top Weight
Inoculation of root-lesion nematode resulted in significant reduction in fresh top
weight of strawberry cultivars. (Fig.4a). Regardless of whether the plants were inoculated
or not, cultivar Camarosa had the highest fresh top weight. This was significantly
different from other strawberry cultivars. The fresh top weight of strawberry cultivars
Festival, Sweet Charlie and Whitney were comparable but significantly lower than
Camarosa. However, they were significantly higher than Winterdawn and Earlibrite
which gave the lowest fresh top weight (Figure 4b). No significant interaction was noted
between nematode inoculation and strawberry cultivars tested (Figure 4c).
Fresh Root Weight
Plants inoculated with lesion nematode gave significantly lower fresh root weight
than uninoculated plants (Figure 5a).Among the cultivars tested, Winterdawn gave
significantly lower fresh root weight than cultivars Festival, Sweet Charlie, Whitney,
Earlibrite and Camarosa (Figure 5b). Statistical analysis revealed no significant
interaction between inoculation and strawberry cultivars in terms of fresh root weight
(Figure 5c).
Plants inoculated with P. penetrans showed varying degrees of root necrosis
(Figure 10). The most severe necrotic lesions were noted in cultivars Camarosa followed
by Festival, Whitney, Winterdawn and Sweet Charlie. Because of severe infection the
cultivar Earlibrite died prematurely. P. penetrans is a migratory endoparasite with all
stage found in root cortex. The nematodes feed mainly on cortex and form cavities
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
15
containing nests or colonies of nematode of all stages. Discoloration of affected tissue is
usually pronounced. Above ground symptoms of attack include chlorosis and stunting
(Bridge et al., 2002). High population of lesion nematodes cause areas of poor growth,
plants are less vigorous, turn yellow and cease to grow. Direct feeding often causes
damage and usually only the cortical tissues are affected. Large nematode populations
cause extensive lesion formation and cortex destruction of unsuberized feeder roots
(Brodie et al., 1981). According to Agrios (1997), the lesion nematodes reduce or inhibit
root development by forming local lesions on young roots, which may then rot with the
entry of secondary fungi and bacteria. As a result of the root damage, affected plants
grow poorly, produce low yields and finally die.
Number of Fruits
Figure 6a, shows the difference between the inoculated and uninoculated
strawberry cultivars. Apparently, inoculated strawberry cultivars gave significantly lower
mean number of fruits than uninoculated ones. Among the strawberry cultivars,
significantly more number of fruits was obtained from Sweet Charlie compared to
Festival, Whitney, Winterdawn, Earlibrite and Camarosa which were comparable (Figure
7b).
Statistical analysis revealed significant interaction between inoculation and
strawberry cultivars. Inoculation of 500 nematodes/pot significantly reduced the number
of fruits of strawberry cultivar Sweet Charlie compared to the uninoculated plant.
Although not significantly different, inoculated plants in cultivars Whitney and
Winterdawn gave lower number of fruits than the uninoculated ones. On the other hand,
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
16
in cultivars Earlibrite, Camarosa and Festival, the inoculated and uninoculated plants
were comparable (Figure 7c).
32
A
31.5
g
(
31
30.5
e
i
ght
30
o
p w
29.5
B
29
28.5
F
r
e
s
h T
28
27.5
Uninoculated
Inoculated
Treatments
50
a
45
40
b
(
g
)
35
b
b
30
e
i
ght
w
25
c
c
op
20
15
F
r
e
s
h t
10
5
0
Fest ival
Sweet
Whit ney
Wint er
Earlibrit e Camarosa
charlie
dawn
Cultivars
50
Uninoculated
Inoculated
a ab
bc
40
cd
c bc
cd
g)
cde
30
ight (
de de
de e
20
Top we
10
0
Festival
Sweet Charlie
Whitney
Winter Dawn
Earlibrite
Camarosa
Cultivars
Fig. 4. Effect of inoculation and strawberry cultivars on fresh top weight; (A)
nematode inoculation; (B) cultivars; (C) interaction of nematode
inoculum and cultivars.
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
17
27.5
A
27
g
(
26.5
26
e
i
ght
w
25.5
oot
25
B
24.5
r
e
s
h R
24
F
23.5
23
Uninoculated
Inoculated
Nem T
at reatm
ode I en
noc t
ulsation
a
g
)
35
(
a
30
a
a
a
25
e
i
g
ht
20
b
w
15
o
ot
10
5
0
F
r
e
s
h r
Festival
Sweet
Whitney
Winter
Earlibrite
Camarosa
charlie
dawn
Cultivars
Uninoculated
Inoculated
a
a
35
a
a
30
ab
ab ab
abc ab
ab
25
bc
20
c
15
oot weight(g) 10
R
5
0
Festival
Sweet Charlie
Whitney
Winter Dawn
Earlibrite
Camarosa
Cultivars
Figure 5. Effect of inoculation and strawberry cultivars on fresh root weight; (A)
nematode inoculation; (B) cultivars; (C) interaction of nematode
inoculum and cultivar
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
18
6
A
t
s
5
B
f
r
ui
4
of
3
ber
2
m
1
Nu
0
Uninoculated
Inoculated
NemT
at reatm
ode In en
oc ts
ulation
a
8
i
ts
7
6
f fru
5
b
b
b
b
b
4
b
e
r
o
3
2
u
m
N
1
0
Fest ival
Sweet
Whit ney
Wint er
Earlibrit e
Camarosa
charlie
dawn
Cultivars
Uninoculated
Inocculated
a
10
8
t
s
(g)
b
b
6
b
b
b
b
b b
b
b b
4
of frui
2
No.
0 Festival Sweet Whitney Winter Earlibrite Camarosa
Charlie
Dawn
Cultivars
Figure 6. Effect of inoculation and strawberry cultivars on number of fruits; (A)
nematode inoculation; (B) cultivars; (C) interaction of nematode
inoculum and cultivar
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
19
Fruit Weight
Inoculation of root-lesion nematodes significantly affected the weight of
Strawberry fruits (Figure 7a). Likewise, highly significant difference was noted among
the strawberry cultivars tested whether they were inoculated or not within the root-lesion
nematode (Figure 7b). In cultivars Sweet Charlie, inoculated plants gave significantly
lower fruits weight than the uninoculated one (Figure 7c).
Number of Nematodes in the Roots
Figure 8, shows the effect of strawberry cultivars on the number of nematodes in
the roots. Apparently, the highest nematode population was noted in cultivars Camarosa
(26,895), however, it did not significantly differ with the cultivars Festival (24,473),
Whitney (17,058) and Winterdawn (12, 481). The lowest nematodes count was recorded
in cultivars Sweet Charlie (5,956) however this is at par with cultivar Earlibrite (10,268).
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
20
60
A
50
g
(
B
40
e
i
ght
i
t
w
30
20
s
h
fru
F
re
10
0
Uninoculated
Uninoculated
Treatments
Nematode Inoculation
100
a
h
80
e
ig
60
b
b
b
b
r
u
it w
b
40
20
F
r
e
s
h
f
0
Fest ival
Sweet
Whit ney
Wint er
Earlibrit e
Camarosa
charlie
dawn
Cultivars
Uninoculated
Inoculated
a
100
)
b
80
bcd
bc
ight(g
60
bcd
bcd
cd
cd
cd
cd
cd
40
d
r
uit we
20
F
0 Festival Sweet Whitney Winter Dawn Earlibrite Camarosa
Charlie
Cultivars
.
Figure 7. Effect of inoculation and strawberry cultivars on fruit weight; (A)
nematode inoculation; (B) cultivars; (C) interaction of nematode
inoculum and cultivar
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
21
Number of Nematodes in the Soil
The effect of strawberry cultivars on the total number of nematodes in the soil is
shown in Figure 9. Highly significant difference was noted among the different
treatments. The highest nematode counts were obtained from cultivars Whitney (855),
this was followed closely with Sweet Charlie, Earlibrite, Festival and Camarosa with 668,
596, 447 and 255 nematodes/pot respectively. The lowest nematode population was noted
on cultivar Winterdawn but this was comparable to Sweet Charlie, Earlibrite, Camarosa
and Festival.
Strawberry cultivars Camarosa and Festival support a large number of nematodes
in the roots. Inspite of this, there was no significant difference observed between
inoculated and uninoculated plants in terms of yield. This could be aform of tolerance,
According to Bernard and Laughlin (1976) a number of potato have been reported to
possess some degree of tolerance to P. penetrans. The cultivar Russet Burbank is
relatively tolerant to infestation by P. penetrans but it does not resist multiplication of
the nematode.
On the other hand, Sweet Charlie supports only fewer nematodes compared to
other cultivars, but its yield was significantly reduced by nematode inoculation. This
shows that the above cultivar is susceptible to the root-lesion nematode.
Results of the present investigation revealed that the strawberry cultivars imported
from California, USA have varying reaction to P. penetrans. Most of the cultivars
evaluated support large number of nematodes in the roots but their yield was not
significantly affected. This indicates tolerance to the root-lesion nematode. However,
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
22
another trial is recommended using higher level of nematode inoculum in order to verify
the above results.
a
30000
a
f
t 25000
r
oo
ab
20000
b
e
r
o
s
i
n
ab
u
m
15000
bc
l n
a
t
o
de
10000
c
ta
to
m
5000
ne
0
Festival
Sweet
Whitney WinterdawnEarlibrite Camarosa
Charlie
cultivars
Fig.8. Effect of P. penetrans on final nematode population in roots of six strawberry
cultivars.
a
900
800
a
o
il
ab
s 700
r
of
600
ab
the 500
mbe
s
in 400
c
l nu
de
ta
to 300
bc
to
200
n
e
ma
100
0 Festival Sweet WhitneyWinterdawnEarlibriteCamarosa
Charlie
cultivars
Fig. 9. Effect of P. penetrans on final nematode population in soil of six strawberry
cultivars.
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
23
A
B
D
C
E
Figure 10. Root system of strawberry cultivars: (A) Sweet Charlie, (B) Whitney, (C)
Festival, (D) Camarosa and (E) Winterdawn
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
24
A
B
Figure 11. Adult P. penetrans (A)male, (B)gravid female
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
SUMMARY, CONCLUSION AND RECOMMENDATION
Summary
A greenhouse experiment was conducted to determine the effect of Pratylenchus
penetrans on the growth and yield of six strawberry cultivars. Inoculation of 500
nematodes/pot did not significantly affect the fresh top weight, fresh root weight and
weight of fruits of Festival, Sweet Charlie, Whitney, Winterdawn, Earlibrite and
Camarosa. However, the number of fruits was significantly reduced by the nematode
inoculation in cultivar Sweet Charlie. On the other hand, the nematode multiplication was
significantly faster in cultivars Camarosa, however, it did not significantly differ with the
Whitney and Winterdawn. The lowest nematode count in the roots was obtained from
Sweet Charlie, Nevertheless, it was comparable to Earlibrite.
Conclusion
Based on the results obtained, it can be inferred that Sweet Charlie is more
susceptib le to the P. penetrans. On the other hand Camarosa and Festival seem to be
more tolerant on the nematodes.
Recommendation
Another study is recommended using higher nematode inoculum in order to fully
evaluate the true reaction of the strawberry cultivars to the root-lesion nematode.
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
LITERATURE CITED
ADAMS, R. E., and C. E. HICKMAN. 1970. Influence of nematicidal treatments and
fungicidal sprays on yield of strawberries. Plant disease Reporter 54: 923-926
AGRIOS, G. N. 1997. Plant Pathology. 4th Ed. University of San Diego, California.
Pp.81-583
ANONYMOUS, 1999. Report on Plant Disease. University of the Illnois. College of
Agriculture. Consumer and Environmental Sciences. Department of the Crop
Sciences.University of Illnois at Urbana Champaign.
http//:web.aces.uiuc.edu/vistal pdf-pubs/1103.pdf. Pp.1-5.
ANONYMOUS, 2002. Lansen Canyon Nursery Commercial Strawberry Growers.
Retrieved February 17, 2006 from http://www.lassencanyonnursery.com/comm.
varieties.
AVERRE III and M.C. SHURTLEFF 2000. Diagnosing Plant Diseases Caused by
Nematodes. APS Press. The American Phytopathological Society St. Paul,
Minnesota. Pp. 119-122.
BERNARD, E. C., and C. W. LAUGHLIN. 1976. Relative susceptibility of selected
cultivars of potato to Pratylenchus penetrans. Journal of Nematology 8: 239-242.
BOERMA, H. R., and HUSSEY. 1992. Breeding for plant resistance to nematodes.
Journal of Nematology 24: 242-252.
BRIDGE, J., M. LUC, R. A. SIKRA, (Ed.). 2002. Plant Parasitic Nematodes in Sub
tropical and Tropical Agriculture. Printed and Bound in United Kingdom:
Antony Rowe Limited Eastbourne. Pp.28 and 147.
BRODIE, B. B., M. B. HARRISON, and W. F. MAI, (1981). Nematodes. In: Hooker
W.J. (Ed.) Compendium of Potato Diseases. American Phytopathological Society.
Pp. 93-101.
KIAT-ONG, B. E. 2005. Survey of Plant Parasitic Nematodes Associated with
Strawberry in Tuba and La Trinidad. BS Thesis. BSU, La Trinidad, Benguet.
KIMPINSKI, J. J., J. F. HANCOCK AND J. S. CAMERON. 1991. Expansion of the
strawberry germplasm base in North America. Pp. 66-75
KURPPA, S. and T. VRAIN, (1989). Effects of Pratylenchus penetrans on the infection
of strawberry roots by Gnomonia comari. Journal of Nematology 21: 511-512.
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
27
POTTER, J. W., and DALE. 1991. Root-lesion nematode tolerance in wild cultivated
strawberry. Pp. 202-208.
POTTER, J. W., and DALE. 1994. Wild and cultivated strawberries can tolerate or resist
root lesion nematode. Hortscience 29: 1074-1077.
RICKETSON, C. L., D. L. TOWNSEND and J. WIEBE, (1966). The effect of spring
application of nematicides on strawberry in the Niagara Peninsula. Canadian
Journal of Plant Science 46: 111-114.
SZCYGIEL, A. 1981. Trials on susceptibility of strawberry cultivars to the root lesion
nematode, Pratylenchus penetrans. Fruit Science Reports 8: 115-119.
SZCYGIEL, A. 1983. On tolerance limit to strawberry plants to root-lesion nematode P.
penetrans (Colb). Fruit Science Reports 10: 135-137.
VILLANUEVA, L. M. 1994. Survey, Pathogenecity and Control of Plant Parasitic
Nematode Associated with Strawberry in the Philippines. Proceedings of the
Second International Workshop on Plant Nematology Karachi, Pakistan. Nov. 22-
26,1992.
VRAIN, T. 1985. Resistance to root-lesion nematode in strawberry. Canadian
Horticultural Council Annual Report for 1985. P 75.
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
APPENDICES
Table 1. Effect of P. penetrans on fresh top weight (g) of six strawberry cultivars.
TREATMENT
REPLICATION
COMBINATION
I II III
TOTAL
IV
MEAN
T1V1 17.5
40.0
27.5
40.0
125.0
31.25
TIV2 27.5
45.5
32.5
40.0
145.5
36.38
T1V3 42.5
30.0
32.5
27.5
132.5
33.13
T1V4 20.0
18.0
20.0
22.5
80.5
20.13
T1V5 22.5
20.0
15.0.
25.0
82.5
20.63
T1V6 50.0
47.5
47.5
42.5
187.5
46.88
Sub-Total 180.0
201.0
175.0
197.5
753.5
31.4
T1V1 25.0
35.25
35.85
25.5
121.6
30.4
TIV2 29.5
22.5
21.1
34.25
107.35
26.84
T1V3 31.5
40.0
34.0
30.0
135.5
33.88
T1V4 24.6
12.8
32.7
14.1
84.3
21.08
T1V5 18.9
25.0
18.2
8.75
70.8
17.7
T1V6 32.7
44.2
53.4
45.5
175.9
43.98
Sub-Total 162.3
179.8
195.3
158.1
695.5
28.98
ANALYSIS OF VARIANCE
SOURCE OF
VARIANCE
DF
SS
MS
F value Pr > F
Model
14
3957.73 282.695
5.86
0.0001
Block
3
63.185 21.062
0.44
0.7281
INOC
1
80.213 80.213 1.66ns 0.2061
TRT
5
3668.91 733.782 15.22**
0.0001
INOC*trt
5
145.422 29.084 0.60ns 0.6978
Error
33
1591.03 48.213
Corrected Total
47
5548.76
ns-not significant Coefficient of variation- 23.07%
**-highly significant
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
29
Table 2. Effect of P. penetrans on root weight (g) of six strawberry cultivars.
TREATMENT
REPLICATION
COMBINATION
I II III
TOTAL
IV MEAN
T1V1
22.5 32.5 40.0 37.5
132.5
33.13
TIV2
30.0 32.5 27.5 32.5
122.5
30.63
T1V3
37.5 17.5 20.0 32.5
107.5
26.88
T1V4
20.0 17.5 20.0 12.5 70.0 17.5
T1V5
31.0 17.5 15.0 35 98.5
24.63
T1V6
27.5 25.0 30.0 37.5
120.0
30.0
Sub-Total 168.5
142.5
152.5
187.5
651
27.13
T1V1 22.15
28.7
29
43.55
123.4
30.84
TIV2 26.55
24.2
25.9
26.4
103
25.75
T1V3 22.5
30.0
30
22.5
105
26.25
T1V4
15.9
8.3
23.5
12.3
60.0
14.99
T1V5 23.55
30.8
21.25
25.5.
101.1
25.26
T1V6 20.5
29.0
26.5
21.25
97.3
24.31
Sub-Total
131.15 150.8 156.15 126 589.6 24.57
ANALYSIS OF VARIANCE
SOURCE OF
VARIATION
DF
SS
MS
F value
Pr > F
Model
14
1346.28 96.163 2.4 0.0192
Block
3
102.395 34.132 0.85 0.4755
INOC
1
78.541 78.541 1.96ns
0.01708
TRT
5
1106.97 221.394 5.53** 0.0008
INOC*trt
5
58.37 11.674 0.29ns 0.913
Error
33
1321.78 40.054
Corrected Total
47
2688.05
ns-not significant Coefficient of variance-25.85%
**- highly significant
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
30
Table 3. Effect of P. penetrans on weight of fruits (g) of six strawberry cultivars
TREATMENT
REPLICATION
COMBINATION
I II III IV
TOTAL
MEAN
T1V1
72.8 47.7 26.15 57.2
203.85
50.96
TIV2 104.85
91.3
100.6
95.45
392.2
98.05
T1V3
46.55
72.4 51.4 43.7
214.05
53.51
T1V4 54.75
31.55
49.8
56.7
192.8
48.2
T1V5 44.25
35.6
68.35
22
173.2
43.3
T1V6 39.6
38.25
60.3
59.3
197.45
49.36
Sub-Total 362.8
316.8
356.6
334.35
1373.55
57.23
T1V1
52.2
56.25 28.1 18.25
154.8 38.7
TIV2 73.05
88.3
76.65
50.05
288.05
72.01
T1V3
46 18.5 38.95 43.6
147.05
36.76
T1V4 12
51.2
42.35
21.65
127
31.75
T1V5 21.3
18.75
45.2
25.9
11.15
27.79
T1V6 50.8
32.15
23.45
35.2
141.6
35.4
Sub-Total
255.35
265.15 254.7 194.65
869.65 40.4
ANALYSIS OF VARIANCE
SOURCE OF
DF
SS
MS
F value
Pr > F
VARIANCE
Model
14
17163.9 1225.95
5.48
0.0001
Block
3
411.323 137.108
0.61
0.6113
INOC
1
3345.01 3345.01 14.96**
0.0005
TRT
5
13170.5 2634.1 11.78**
0.0001
INOC*trt
5
236.441 47.288 0.21ns 0.9552
Error
33
7378.27
223.584
Corrected Total
47
24541.5
ns-not significant Coefficient of variation- 48.76%
**-highly significant
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
31
Table 4. Effect of P. penetrans on number of fruits of six strawberry cultivars.
TREATMENT
REPLICATION
COMBINATION
I II III IV TOTAL MEAN
T1V1 4.5
3.5
1.5
4.5
14
4
TIV2 12.5
10
10.5
7.5
40.5
10
T1V3 3.5
5.5
4
5.5
18.5
5
T1V4 4.5
3.5
4.5
6
18.5
5
T1V5 4.5
4
5.5
2
16
4
T1V6 5
3.5
4
5
17.5
4
Sub-Total 34.5
30
30
30.5
125
5.33
T1V1 6
7
2
2.5
17.5
4
TIV2 8
3
2
7
20
5
T1V3 4.5
2
3.5
5
15
4
T1V4 1
5
4.5
2.5
13
3
T1V5 4.5
2.5
4.5
3.5
16
4
T1V6 5
3.5
3.5
4
16
4
Sub-Total 29
23
20
24.5
97.5
4
ANALYSIS OF VARIANCE
SOURCE OF
VARIANCE
DF
SS
MS
F value
Pr > F
Model 14
152.323
10.88
4.02
0.0005
Block 3
8.391
2.707
1.03
0.3904
INOC 1
16.922
16.922
6.25**
0.0175
TRT 5
84.151
16.83
6.22**
0.0004
INOC*trt 5
42.859
8.572
3.17*
0.0192
Error 33
85.297
2.706
Corrected Total
47
241.619
*-significant Coefficient of variation- 35.65%
**-highly significant
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
32
Table 5. Effect of P. penetrans on final nematode population in roots
TREATMENT
REPLICATION
COMBINATION
I II
III
TOTAL MEAN
IV
Raw Data
T2V1 4550
6115.88 8711.55
5096
24473.4
6118.36
T2V2 1829
1935
822.9
1370
5956.9
1489.23
T2V3 1354.5
7360
3094
5250
17058.5
4264.63
T2V4 2575.93
4806.4
3209.5
1889.4
12481.2
3120.31
T2V5 1748.25
3775
807.68
3937.5
10268.4
2567.11
T2V6 1735.75
1747.88 20158.5 3253.25
26895.4
6723.85
Sub-total 13793.4
25740.2 36804.1 20796.2
97133.9
4047.24
Transfomed Data
T2V1 3.66
3.79
3.94
3.71
15.09
3.77
T2V2 3.26
3.29
2.92
3.14
12.6
3.15
T2V3 3.13
3.87
3.49
3.72
14.21
3.55
T2V4 3.41
3.68
3.51
3.28
13.88
3.47
T2V5 3.24
3.58
2.91
3.6
13.32
3.33
T2V6 3.24
3.24
4.3
3.51
14.3
3.57
Sub-total 19.95
21.44
21.06
20.95
83.4
20.85
ANALYSIS OF VARIANCE
SOURCE OF
VARIANCE
DF SS MS
Computed
F
Block
3 0.208 0.0609 0.7473
Trt 5
0.919
0.184
1.9810ns
Error 15
1.392
0.093
Corrected Total
23
2.520
ns- not signicant Coeffecient of variation= 8.77%
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
33
Table 6. Effect of P. penetrans on final nematode population in soil.
TREATMENT
REPLICATION
COMBINATION I
II III IV
TOTAL
MEAN
Raw Data
T2V1 64.50
127.50
142.50
112.50
447.00
111.75
T2V2 123.75
393.75
101.25
48.75
667.50
166.88
T2V3 56.25
465.00
266.25
67.50
855.00
213.75
T2V4 56.25
33.75
33.75
30.00
153.75
38.44
T2V5 116.25
172.50
123.75
183.75
596.25
149.06
T2V6 56.25
116.25
67.15
15.00
254.65
63.66
Sub-total 473.25
1308.75 734.65
457.50
2974.15
123.92
Transfomed Data
T2V1 1.81
2.11
2.15
2.05
2.650
2.030
T2V2 2.09
2.60
2.01
1.69
2.824
2.095
T2V3 1.75
2.67
2.43
1.83
2.932
2.168
T2V4 1.75
1.53
1.53
1.48
2.187
1.571
T2V5 2.07
2.24
2.09
2.26
2.775
2.165
T2V6 1.75
2.07
1.83
1.18
2.406
1.705
ANALYSIS OF VARIANCE
SOURCE OF
VARIANCE DF
SS
MS Computed
F
Block 3
1.97
0.22
0.5949
Trt 5
0.67
0.26
8.8936**
Error 15
1.3
0.62
Corrected Total
23
2.91
**-highly significant Coeffecient of variation-21.58%
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
FLORES, MARICAR F. APRIL 2007. Effect of Lesion Nematode (Pratylenchus
penetrans Filipjev and Shuurmans Stekhoven) on the Growth and Yield of Six Strawberry
Cultivars (Fragaria x ananassa Duch). Benguet State University, La Trinidad, Benguet.
Adviser: Luciana M. Villanueva, Ph.D
ABSTRACT
The study was conducted at BIOCON Laboratory and Greenhouse, Horticultural
Research and Training Institute (HORTI), Benguet State University, La Trinidad,
Benguet to determine the effect of Pratylenchus penetrans on the growth and yield of six
strawberry cultivars.
Inoculation of 500 nematodes/pot did not significantly affect the fresh top weight,
fresh root weight, weight of fruits of Strawberry cultivars: Festival, Sweet Charlie,
Whitney, Winterdawn, Earlibrite and Camarosa. However, the number of fruits was
significantly reduced by the nematode inoculation in cultivar Sweet Charlie. The
nematode multiplication was significantly faster in cultivar Camarosa, however, it did not
significantly differ with Whitney and Wintedawn. The lowest nematode count in the
roots was obtained from Sweet Charlie, nevertheless, it was comparable to Earlibrite.
Based on the results it could be inferred that Sweet Charlie is more susceptible to
the P. Penetrans. On the other hand, Camarosa and Festival seem to be more tolerant to
nematodes.
TABLE OF CONTENTS
Page
Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
Table of Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
REVIEW OF LITERATURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
MATERIALS AND METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Source of Nematode Inoculum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Sterilization of Nematode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Inoculation of Root Lesion Nematode . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
RESULTS AND DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14
Fresh Top Weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Root Weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Number of Fruits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14
Fruit Weight. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Number of Nematode in Roots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Number of Nematode in Soil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
SUMMARY, CONCLUSION AND RECOMMENDATION . . . . . . . . . . . . . 25
LITERATURE CITED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
APPENDICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
ii
INTRODUCTION
The lesion nematode, Pratylenchus penetrans (Cobb) Filipjev and Schuurmans
Stekhoven has been found to infest and be pathogenic on the cultivated strawberry,
Fragaria x ananassa Duch (Potter and Dale, 1991). Several studies have observed that
lesion nematode reproduction varies on different cultivars. In West Virginia, Midway
strawberry appeared to be a better host than Surecrop (Adams and Hickman, 1970). In
Price Edward Island, significantly more Pratylenchus sp. were found in the cultivar
Cavalier than in Veestar, Redcoat, or Vibrant, and redcoat harbored more than Micmac
(Kimpinski, 1985). In the Pacific Northwest, no useful resistance was found in 14
cultivars, although the nematode multiplied more rapidly on some cultivars than on
others.
In the Philippines, P. penetrans was one of the plant parasitic nematodes found
associated with strawberry in Benguet and Baguio City (Villanueva, 1994). It occurred in
high population densities in all the fields surveyed and considered to be an active parasite
of strawberry in the area (Kiat-ong, 2005). Based on the above and below ground
symptoms, most of the strawberry cultivars grown are susceptible to the nematode.
Lesion nematodes reduce or inhibit root development by forming local lesions on young
roots, which may then rot with the entry of secondary fungi and bacteria. As a result of
the root damage, affected plants grow poorly, produce low yields, and may finally die
(Agrios, 1997).
The strawberry can both resist and tolerate the lesion nematode (Potter and Dale,
1994). Here we use the terminology of Boerma and Hussey (1992) to describe resistance
and tolerance. Resistance describes the ability of a host to suppress nematode
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
2
development and reproduction, and tolerance describe the sensitivity of a host to
parasitism or the amount of damage sustained.
The study was conducted at the BIOCON Laboratory and Greenhouse,
Horticultural Research and Training Institute, Benguet State University, La Trinidad,
Benguet from November, 2006 to March, 2007 to determine the effect of Pratylenchus
penetrans on growth and yield of six strawberry cultivars imported from California,
USA.
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
REVIEW OF LITERATURE
The strawberry, a perennial herb of the genus Fragaria of the Rose family is a
strange plant to many Filipinos particularly among the lowlanders. It is a semi-temperate
and photoperiodic crop. Its sweet juicy fruit is one of the highly priced commodities in
Baguio despite its abundance during the months of December to April. The crop is only
produced in Baguio-Benguet area of the Northern Philippines where the climate is unique
Recently, five strawberry cultivars were imported from California, USA. They are
Camarosa, Strawberry Festival, Earlibrite, Whitney and Winter Dawn. Camarosa, is an
early short day variety. The vigorous plants produce large fruit throughout the most
fruiting cycle. The interior color of Camarosa is a brilliant red and fruit colors uniformly.
Yield potential is high to excellent in University of California performance tests.
Strawberry Festival is also a short day cultivar. The fruits are mostly conic in shape. The
external color of mature fruit is deep red and glossy while the internal color is bright red.
The fruits of Strawberry Festival have very firm texture and excellent flavor. Strawberry
Festival has a fruiting pattern and yield similar to that of Camarosa. Sweet Charlie is an
early maturing sweet cultivar. The plant is medium in size making harvesting easy. Sweet
Charlie has also anthracnose tolerance. On the other hand, Earlibrite originated from
1993 cross between Rosalinda and FL 90-38. It is an early producer. Usually in
December it produces bright red fruits (Anonymous, 2002).
The lesion nematode, Pratylenchus penetrans (Cobb) Filipjev and Schuurmans
Stekhoven has been found to infest and be pathogenic on the cultivated strawberry,
Fragaria x ananassa Dutch (Potter and Dale, 1991). Several studies have observed that
lesion nematode reproduction varies on different cultivars. In West Virginia, Midway
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
4
strawberry appeared to be a better host than Surecrop (Adams and Hickman, 1970). In
Price Edward Island, significantly more Pratylenchus sp. were found in the cultivar
Cavalier than in Veestar, Redcoat, or Vibrant, and Redcoat harbored more nematodes
than Micmac (Kimpinski, 1985). In the Pacific Northwest, no useful resistance was
found in 14 cultivars, although the nematode multiplied more rapidly on some cultivars
than on others. For instance, they were able to reproduce readily on the cultivars
Olympus, Shuksan and Tyee, and less on Rainier (Vrain, 1985).
In Poland, Szczygiel (1981) evaluated 28 strawberry cultivars in pots for P.
penetrans susceptibility in terms of nematode numbers per gram of root and tolerance on
the bases of degree of root necrosis and reduction of plant growth. Also European and
North American cultivars were compared. While no strawberry was completely resistant
to P. penetrans, Guardian, Redchief and Sengana supported lower numbers of
nematodes, whereas Midway, Vesper and Grenadier supported large numbers. The latter
three cultivars also ranked among the highest in root necrosis, along with Cambridge
Favourite, whereas Guardian and Senga sengana were almost equally low on root
necrosis index. However, Midway and to a lesser extent, Vesper and Grenadier, did not
show reduced growth commensurate with the root necrosis index or large numbers of
nematodes. Szczygiel (1981) concluded that both root necrosis and reduced growth
should be evaluated to indicate nematode-induced damage to a cultivar.
The strawberry can both resist and tolerate the northern lesion nematode (Potter
and Dale, 1994). Here we use the terminology of Boerma and Hussey (1992) to describe
resistance and tolerance. Resistance describes the ability of a host to suppress nematode
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
5
development and reproduction, and tolerance describes the sensitivity of a host to
parasitism or the amount of damage sustained.
P. penetrans is a migratory endoparasite with all stages found in root cortex. Low
soil population can be associated with high root population. The nematodes feed mainly
on cortex and form cavities containing nests or colonies of nematode of all stages.
Discoloration of affected tissues is usually pronounced. Above ground symptoms of
attack include chlorosis and stunting (Bridge et al., 2002). High populations of lesion
nematodes cause areas of poor growth; plants are less vigorous, turn yellow and cease to
grow. Direct feeding often causes damage and, usually, only cortical tissues are affected.
Large nematode populations cause extensive lesion formation and cortex destruction of
unsuberized feeder roots (Brodie et al., 1981).
According to Anonymous (1999) the symptoms on infected roots are small, light
to dark brown lesions. The lesions tend to expand and to merge as the growing season
progresses, giving the roots a discolored appearance overall. Nematode feeding causes
cortical tissue disintegration and girdling, resulting in the sloughing off of the epidermis
and remaining cortex, root pruning, and the reduction in size of the root system. The roots
of severely infected plants maybe almost complete. Lesion formation results from an
interaction of plant glycosides with enzyme released by the nematode during feeding.
The chemicals are toxic to invaded and adjacent host cells. The degree of host parasite
interaction depends on the concentration and location of specific glycosides within the
root tissue on the concentration of enzymes released during feeding. The wounds produce
by the nematodes provide a means of entry for a wide variety of relatively and
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
6
nonspecific soil microorganisms, including root infecting pathogens that may also
contribute to lesion formation and may enhance the disease.
Pratylenchus penetrans, the main species pathogenic to strawberry, was also
found to carry spores of Gnomonia comari, the cause of leaf blotch (Kurppa and Vrain,
1989). These nematodes prefer coarse-textured, sandy soils. In temperate climates, they
over winter in roots or in soil as eggs, juveniles, or adults. During periods of drought,
they are quiescent and susceptible to drying if the soil is plowed and fallowed through hot
months. Where soil moisture is low some species can survive more than a year without a
host crop. Species of Pratylenchus are unusual in reproducing in larger numbers in
stressed plants. In all motile stages, this nematode can invade and leave roots, so there is
no infective stage. To estimate the size of population of Pratylenchus species, both roots
and soil should be sampled. Staining of roots suspected of harboring these nematodes or
extraction from such roots may be necessary to confirm their presence (Averre III et al.,
2000).
All species of Pratylenchus are readily distributed with the infected planting
material and, consequently, P. penetrans is widely distributed wherever strawberries are
grown. Several other species have been associated with strawberry but not all are
damaging. Damage by P. penetrans is greatest on light soils where a threshold of 50
nematodes 100g soil has been reported (Szczygiel, 1983).
Currently, nematode management considerations include crop rotation of less
susceptible crops and resistant varieties, cultural and tillage practices, use of transplants
and preplant nematicide treatments. These methods unlike other chemical methods tend
to reduce nematode population gradually overtime. Lesion nematodes can be best
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
7
controlled by overall or row treatment of the soil with the nematicides before the crop is
planted. Such treatments give good control of these nematodes, but they usually fail to
eradicate them completely. In hot and dry climates fairly good control of lesion nematode
can be achieved by summer fallow, which requires the nematode population by exposing
them to heat and drying by eliminating the host plants. Control through crop rotation is
rather unsuccessful because of the wide host range of the lesion nematodes. Several fungi
and bacteria that parasitize and kill lesion nematodes are known, but none are effective as
biological control agents under field conditions (Agrios, 1997).
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
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 from November 2006 to March 2007. There were two treatments replicated four
times with two sample plants per replicate. The treatments were arranged randomly in
greenhouse using the Randomized Complete Block Design (RCBD) involving factorial
arrangement. Six strawberry cultivars were used namely: Camarosa, Festival, Sweet
Charlie, Earlibrite, Whitney and Winter Dawn (Figure1).
Fig. 1. Experimental lay-out (RCBD)
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
9
The soil used in the experiment was obtained from the Benguet State University
Experimental Area located at Balili, La Trinidad, Benguet containing a mixture of rice
hull and sand together with the soil. It was heat-sterilized prior to use to get rid of other
soil-borne pathogens that will affect the development of nematodes.
Source of Nematode Inoculum
The nematodes were cultured in carrot discs. Healthy carrot roots were washed in
running water to remove the adhering soil particles and blot dried in tissue paper. It was
surfaced sterilized with 70% ethanol and peeled three times Carrots were cut into discs
and placed in sterile Petri dishes.
The infected roots were washed thoroughly with tap water and cut into small
pieces. These were macerated with a kitchen blender and passed through a 40-micrometer
sieve. The mixture of blended roots and nematodes from the sieve were placed overnight
in a Baerman funnel. This allowed the nematodes to pass through the sieve to the water
and the blended root tissue to remain. The residue in the sieve was rinsed with
tap water to eliminate bacteria, etc. The nematodes were collected from the sieve with
distilled water.
Sterilization of Nematodes
In order to establish a culture with the least possible contamination, it is important
to use clean nematode solution. The nematode suspension was transferred into a sterile
test tube containing sterile distilled water using a sterile pipette. About .6 ml of 600-ppm
streptomycin sulphate was added in 2 ml nematode suspension. The nematode suspension
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
10
was left overnight in sealed test tube; the streptomycin sulphate solution was removed
from above the nematodes and which was allowed to settle at the bottom of the test tube
for an hour. The water was removed and fresh sterile water is added. The process was
repeated three times.
Inoculation of the Lesion Nematode
Six strawberry cultivars were used namely: Camarosa, Festival, Sweet Charlie,
Earlibrite, Whitney and Winter Dawn. The inoculum was introduced in 4 holes near the
root zone and later covered again with soil. Uninoculated plants were provided to serve
as control.
The different treatments were the following:
Factor A: Inoculum Levels
T1-0
T2-500 nematodes/plant
Factor B: Variety
V1- Festival
V2- Sweet Charlie
V3- Whitney
V4- Winter dawn
V5- Earlibrite
V6- Camarosa
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
11
All the cultural management practices in strawberry production such as watering,
fertilization, removal of old leaves and control of pests except nematode was employed
uniformly in all the treatments to ensure good growth and yield of the plant.
Data Gathered
1. Top weight (g). This refers to the weight of the upper part of the plant after
harvest.
2. Root weight (g). This refers to the weight of the roots after harvest.
3. Number and weight of fruits/plant. This refers to number and weight of fruits
harvested per sample plant.
4. Number of nematodes in the roots. This was obtained by collecting one gram
of roots. The nematodes were extracted using a blender and nematodes were
collected using the blue sieve method (Figure 2).
5.
Number of nematodes in the soil. This was obtained by collecting 200 cc of
soil and processed using the Modified Tray Method (Figure 3).
The data were analyzed statistically using Analysis of Variance (ANOVA) and
treatment means were separated using the Duncan’s Multiple Range Test (DMRT).
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
12
(a) Blender (b) Blue sieve
Fig. 2. Extraction of nematode from the roots using (a) blender and (b) blue sieve
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
13
B
A
C
D
Fig. 3. M0dified tray method of isolating nematodes from soil placed in mayonnaise
bottle (A&B), collection opf nematode suspension (C&D)
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
RESULTS AND DISCUSSIONS
Fresh Top Weight
Inoculation of root-lesion nematode resulted in significant reduction in fresh top
weight of strawberry cultivars. (Fig.4a). Regardless of whether the plants were inoculated
or not, cultivar Camarosa had the highest fresh top weight. This was significantly
different from other strawberry cultivars. The fresh top weight of strawberry cultivars
Festival, Sweet Charlie and Whitney were comparable but significantly lower than
Camarosa. However, they were significantly higher than Winterdawn and Earlibrite
which gave the lowest fresh top weight (Figure 4b). No significant interaction was noted
between nematode inoculation and strawberry cultivars tested (Figure 4c).
Fresh Root Weight
Plants inoculated with lesion nematode gave significantly lower fresh root weight
than uninoculated plants (Figure 5a).Among the cultivars tested, Winterdawn gave
significantly lower fresh root weight than cultivars Festival, Sweet Charlie, Whitney,
Earlibrite and Camarosa (Figure 5b). Statistical analysis revealed no significant
interaction between inoculation and strawberry cultivars in terms of fresh root weight
(Figure 5c).
Plants inoculated with P. penetrans showed varying degrees of root necrosis
(Figure 10). The most severe necrotic lesions were noted in cultivars Camarosa followed
by Festival, Whitney, Winterdawn and Sweet Charlie. Because of severe infection the
cultivar Earlibrite died prematurely. P. penetrans is a migratory endoparasite with all
stage found in root cortex. The nematodes feed mainly on cortex and form cavities
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
15
containing nests or colonies of nematode of all stages. Discoloration of affected tissue is
usually pronounced. Above ground symptoms of attack include chlorosis and stunting
(Bridge et al., 2002). High population of lesion nematodes cause areas of poor growth,
plants are less vigorous, turn yellow and cease to grow. Direct feeding often causes
damage and usually only the cortical tissues are affected. Large nematode populations
cause extensive lesion formation and cortex destruction of unsuberized feeder roots
(Brodie et al., 1981). According to Agrios (1997), the lesion nematodes reduce or inhibit
root development by forming local lesions on young roots, which may then rot with the
entry of secondary fungi and bacteria. As a result of the root damage, affected plants
grow poorly, produce low yields and finally die.
Number of Fruits
Figure 6a, shows the difference between the inoculated and uninoculated
strawberry cultivars. Apparently, inoculated strawberry cultivars gave significantly lower
mean number of fruits than uninoculated ones. Among the strawberry cultivars,
significantly more number of fruits was obtained from Sweet Charlie compared to
Festival, Whitney, Winterdawn, Earlibrite and Camarosa which were comparable (Figure
7b).
Statistical analysis revealed significant interaction between inoculation and
strawberry cultivars. Inoculation of 500 nematodes/pot significantly reduced the number
of fruits of strawberry cultivar Sweet Charlie compared to the uninoculated plant.
Although not significantly different, inoculated plants in cultivars Whitney and
Winterdawn gave lower number of fruits than the uninoculated ones. On the other hand,
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
16
in cultivars Earlibrite, Camarosa and Festival, the inoculated and uninoculated plants
were comparable (Figure 7c).
32
A
31.5
g
(
31
30.5
e
i
ght
30
o
p w
29.5
B
29
28.5
F
r
e
s
h T
28
27.5
Uninoculated
Inoculated
Treatments
50
a
45
40
b
(
g
)
35
b
b
30
e
i
ght
w
25
c
c
op
20
15
F
r
e
s
h t
10
5
0
Fest ival
Sweet
Whit ney
Wint er
Earlibrit e Camarosa
charlie
dawn
Cultivars
50
Uninoculated
Inoculated
a ab
bc
40
cd
c bc
cd
g)
cde
30
ight (
de de
de e
20
Top we
10
0
Festival
Sweet Charlie
Whitney
Winter Dawn
Earlibrite
Camarosa
Cultivars
Fig. 4. Effect of inoculation and strawberry cultivars on fresh top weight; (A)
nematode inoculation; (B) cultivars; (C) interaction of nematode
inoculum and cultivars.
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
17
27.5
A
27
g
(
26.5
26
e
i
ght
w
25.5
oot
25
B
24.5
r
e
s
h R
24
F
23.5
23
Uninoculated
Inoculated
Nem T
at reatm
ode I en
noc t
ulsation
a
g
)
35
(
a
30
a
a
a
25
e
i
g
ht
20
b
w
15
o
ot
10
5
0
F
r
e
s
h r
Festival
Sweet
Whitney
Winter
Earlibrite
Camarosa
charlie
dawn
Cultivars
Uninoculated
Inoculated
a
a
35
a
a
30
ab
ab ab
abc ab
ab
25
bc
20
c
15
oot weight(g) 10
R
5
0
Festival
Sweet Charlie
Whitney
Winter Dawn
Earlibrite
Camarosa
Cultivars
Figure 5. Effect of inoculation and strawberry cultivars on fresh root weight; (A)
nematode inoculation; (B) cultivars; (C) interaction of nematode
inoculum and cultivar
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
18
6
A
t
s
5
B
f
r
ui
4
of
3
ber
2
m
1
Nu
0
Uninoculated
Inoculated
NemT
at reatm
ode In en
oc ts
ulation
a
8
i
ts
7
6
f fru
5
b
b
b
b
b
4
b
e
r
o
3
2
u
m
N
1
0
Fest ival
Sweet
Whit ney
Wint er
Earlibrit e
Camarosa
charlie
dawn
Cultivars
Uninoculated
Inocculated
a
10
8
t
s
(g)
b
b
6
b
b
b
b
b b
b
b b
4
of frui
2
No.
0 Festival Sweet Whitney Winter Earlibrite Camarosa
Charlie
Dawn
Cultivars
Figure 6. Effect of inoculation and strawberry cultivars on number of fruits; (A)
nematode inoculation; (B) cultivars; (C) interaction of nematode
inoculum and cultivar
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
19
Fruit Weight
Inoculation of root-lesion nematodes significantly affected the weight of
Strawberry fruits (Figure 7a). Likewise, highly significant difference was noted among
the strawberry cultivars tested whether they were inoculated or not within the root-lesion
nematode (Figure 7b). In cultivars Sweet Charlie, inoculated plants gave significantly
lower fruits weight than the uninoculated one (Figure 7c).
Number of Nematodes in the Roots
Figure 8, shows the effect of strawberry cultivars on the number of nematodes in
the roots. Apparently, the highest nematode population was noted in cultivars Camarosa
(26,895), however, it did not significantly differ with the cultivars Festival (24,473),
Whitney (17,058) and Winterdawn (12, 481). The lowest nematodes count was recorded
in cultivars Sweet Charlie (5,956) however this is at par with cultivar Earlibrite (10,268).
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
20
60
A
50
g
(
B
40
e
i
ght
i
t
w
30
20
s
h
fru
F
re
10
0
Uninoculated
Uninoculated
Treatments
Nematode Inoculation
100
a
h
80
e
ig
60
b
b
b
b
r
u
it w
b
40
20
F
r
e
s
h
f
0
Fest ival
Sweet
Whit ney
Wint er
Earlibrit e
Camarosa
charlie
dawn
Cultivars
Uninoculated
Inoculated
a
100
)
b
80
bcd
bc
ight(g
60
bcd
bcd
cd
cd
cd
cd
cd
40
d
r
uit we
20
F
0 Festival Sweet Whitney Winter Dawn Earlibrite Camarosa
Charlie
Cultivars
.
Figure 7. Effect of inoculation and strawberry cultivars on fruit weight; (A)
nematode inoculation; (B) cultivars; (C) interaction of nematode
inoculum and cultivar
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
21
Number of Nematodes in the Soil
The effect of strawberry cultivars on the total number of nematodes in the soil is
shown in Figure 9. Highly significant difference was noted among the different
treatments. The highest nematode counts were obtained from cultivars Whitney (855),
this was followed closely with Sweet Charlie, Earlibrite, Festival and Camarosa with 668,
596, 447 and 255 nematodes/pot respectively. The lowest nematode population was noted
on cultivar Winterdawn but this was comparable to Sweet Charlie, Earlibrite, Camarosa
and Festival.
Strawberry cultivars Camarosa and Festival support a large number of nematodes
in the roots. Inspite of this, there was no significant difference observed between
inoculated and uninoculated plants in terms of yield. This could be aform of tolerance,
According to Bernard and Laughlin (1976) a number of potato have been reported to
possess some degree of tolerance to P. penetrans. The cultivar Russet Burbank is
relatively tolerant to infestation by P. penetrans but it does not resist multiplication of
the nematode.
On the other hand, Sweet Charlie supports only fewer nematodes compared to
other cultivars, but its yield was significantly reduced by nematode inoculation. This
shows that the above cultivar is susceptible to the root-lesion nematode.
Results of the present investigation revealed that the strawberry cultivars imported
from California, USA have varying reaction to P. penetrans. Most of the cultivars
evaluated support large number of nematodes in the roots but their yield was not
significantly affected. This indicates tolerance to the root-lesion nematode. However,
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
22
another trial is recommended using higher level of nematode inoculum in order to verify
the above results.
a
30000
a
f
t 25000
r
oo
ab
20000
b
e
r
o
s
i
n
ab
u
m
15000
bc
l n
a
t
o
de
10000
c
ta
to
m
5000
ne
0
Festival
Sweet
Whitney WinterdawnEarlibrite Camarosa
Charlie
cultivars
Fig.8. Effect of P. penetrans on final nematode population in roots of six strawberry
cultivars.
a
900
800
a
o
il
ab
s 700
r
of
600
ab
the 500
mbe
s
in 400
c
l nu
de
ta
to 300
bc
to
200
n
e
ma
100
0 Festival Sweet WhitneyWinterdawnEarlibriteCamarosa
Charlie
cultivars
Fig. 9. Effect of P. penetrans on final nematode population in soil of six strawberry
cultivars.
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
23
A
B
D
C
E
Figure 10. Root system of strawberry cultivars: (A) Sweet Charlie, (B) Whitney, (C)
Festival, (D) Camarosa and (E) Winterdawn
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
24
A
B
Figure 11. Adult P. penetrans (A)male, (B)gravid female
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
SUMMARY, CONCLUSION AND RECOMMENDATION
Summary
A greenhouse experiment was conducted to determine the effect of Pratylenchus
penetrans on the growth and yield of six strawberry cultivars. Inoculation of 500
nematodes/pot did not significantly affect the fresh top weight, fresh root weight and
weight of fruits of Festival, Sweet Charlie, Whitney, Winterdawn, Earlibrite and
Camarosa. However, the number of fruits was significantly reduced by the nematode
inoculation in cultivar Sweet Charlie. On the other hand, the nematode multiplication was
significantly faster in cultivars Camarosa, however, it did not significantly differ with the
Whitney and Winterdawn. The lowest nematode count in the roots was obtained from
Sweet Charlie, Nevertheless, it was comparable to Earlibrite.
Conclusion
Based on the results obtained, it can be inferred that Sweet Charlie is more
susceptib le to the P. penetrans. On the other hand Camarosa and Festival seem to be
more tolerant on the nematodes.
Recommendation
Another study is recommended using higher nematode inoculum in order to fully
evaluate the true reaction of the strawberry cultivars to the root-lesion nematode.
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
LITERATURE CITED
ADAMS, R. E., and C. E. HICKMAN. 1970. Influence of nematicidal treatments and
fungicidal sprays on yield of strawberries. Plant disease Reporter 54: 923-926
AGRIOS, G. N. 1997. Plant Pathology. 4th Ed. University of San Diego, California.
Pp.81-583
ANONYMOUS, 1999. Report on Plant Disease. University of the Illnois. College of
Agriculture. Consumer and Environmental Sciences. Department of the Crop
Sciences.University of Illnois at Urbana Champaign.
http//:web.aces.uiuc.edu/vistal pdf-pubs/1103.pdf. Pp.1-5.
ANONYMOUS, 2002. Lansen Canyon Nursery Commercial Strawberry Growers.
Retrieved February 17, 2006 from http://www.lassencanyonnursery.com/comm.
varieties.
AVERRE III and M.C. SHURTLEFF 2000. Diagnosing Plant Diseases Caused by
Nematodes. APS Press. The American Phytopathological Society St. Paul,
Minnesota. Pp. 119-122.
BERNARD, E. C., and C. W. LAUGHLIN. 1976. Relative susceptibility of selected
cultivars of potato to Pratylenchus penetrans. Journal of Nematology 8: 239-242.
BOERMA, H. R., and HUSSEY. 1992. Breeding for plant resistance to nematodes.
Journal of Nematology 24: 242-252.
BRIDGE, J., M. LUC, R. A. SIKRA, (Ed.). 2002. Plant Parasitic Nematodes in Sub
tropical and Tropical Agriculture. Printed and Bound in United Kingdom:
Antony Rowe Limited Eastbourne. Pp.28 and 147.
BRODIE, B. B., M. B. HARRISON, and W. F. MAI, (1981). Nematodes. In: Hooker
W.J. (Ed.) Compendium of Potato Diseases. American Phytopathological Society.
Pp. 93-101.
KIAT-ONG, B. E. 2005. Survey of Plant Parasitic Nematodes Associated with
Strawberry in Tuba and La Trinidad. BS Thesis. BSU, La Trinidad, Benguet.
KIMPINSKI, J. J., J. F. HANCOCK AND J. S. CAMERON. 1991. Expansion of the
strawberry germplasm base in North America. Pp. 66-75
KURPPA, S. and T. VRAIN, (1989). Effects of Pratylenchus penetrans on the infection
of strawberry roots by Gnomonia comari. Journal of Nematology 21: 511-512.
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
27
POTTER, J. W., and DALE. 1991. Root-lesion nematode tolerance in wild cultivated
strawberry. Pp. 202-208.
POTTER, J. W., and DALE. 1994. Wild and cultivated strawberries can tolerate or resist
root lesion nematode. Hortscience 29: 1074-1077.
RICKETSON, C. L., D. L. TOWNSEND and J. WIEBE, (1966). The effect of spring
application of nematicides on strawberry in the Niagara Peninsula. Canadian
Journal of Plant Science 46: 111-114.
SZCYGIEL, A. 1981. Trials on susceptibility of strawberry cultivars to the root lesion
nematode, Pratylenchus penetrans. Fruit Science Reports 8: 115-119.
SZCYGIEL, A. 1983. On tolerance limit to strawberry plants to root-lesion nematode P.
penetrans (Colb). Fruit Science Reports 10: 135-137.
VILLANUEVA, L. M. 1994. Survey, Pathogenecity and Control of Plant Parasitic
Nematode Associated with Strawberry in the Philippines. Proceedings of the
Second International Workshop on Plant Nematology Karachi, Pakistan. Nov. 22-
26,1992.
VRAIN, T. 1985. Resistance to root-lesion nematode in strawberry. Canadian
Horticultural Council Annual Report for 1985. P 75.
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
APPENDICES
Table 1. Effect of P. penetrans on fresh top weight (g) of six strawberry cultivars.
TREATMENT
REPLICATION
COMBINATION
I II III
TOTAL
IV
MEAN
T1V1 17.5
40.0
27.5
40.0
125.0
31.25
TIV2 27.5
45.5
32.5
40.0
145.5
36.38
T1V3 42.5
30.0
32.5
27.5
132.5
33.13
T1V4 20.0
18.0
20.0
22.5
80.5
20.13
T1V5 22.5
20.0
15.0.
25.0
82.5
20.63
T1V6 50.0
47.5
47.5
42.5
187.5
46.88
Sub-Total 180.0
201.0
175.0
197.5
753.5
31.4
T1V1 25.0
35.25
35.85
25.5
121.6
30.4
TIV2 29.5
22.5
21.1
34.25
107.35
26.84
T1V3 31.5
40.0
34.0
30.0
135.5
33.88
T1V4 24.6
12.8
32.7
14.1
84.3
21.08
T1V5 18.9
25.0
18.2
8.75
70.8
17.7
T1V6 32.7
44.2
53.4
45.5
175.9
43.98
Sub-Total 162.3
179.8
195.3
158.1
695.5
28.98
ANALYSIS OF VARIANCE
SOURCE OF
VARIANCE
DF
SS
MS
F value Pr > F
Model
14
3957.73 282.695
5.86
0.0001
Block
3
63.185 21.062
0.44
0.7281
INOC
1
80.213 80.213 1.66ns 0.2061
TRT
5
3668.91 733.782 15.22**
0.0001
INOC*trt
5
145.422 29.084 0.60ns 0.6978
Error
33
1591.03 48.213
Corrected Total
47
5548.76
ns-not significant Coefficient of variation- 23.07%
**-highly significant
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
29
Table 2. Effect of P. penetrans on root weight (g) of six strawberry cultivars.
TREATMENT
REPLICATION
COMBINATION
I II III
TOTAL
IV MEAN
T1V1
22.5 32.5 40.0 37.5
132.5
33.13
TIV2
30.0 32.5 27.5 32.5
122.5
30.63
T1V3
37.5 17.5 20.0 32.5
107.5
26.88
T1V4
20.0 17.5 20.0 12.5 70.0 17.5
T1V5
31.0 17.5 15.0 35 98.5
24.63
T1V6
27.5 25.0 30.0 37.5
120.0
30.0
Sub-Total 168.5
142.5
152.5
187.5
651
27.13
T1V1 22.15
28.7
29
43.55
123.4
30.84
TIV2 26.55
24.2
25.9
26.4
103
25.75
T1V3 22.5
30.0
30
22.5
105
26.25
T1V4
15.9
8.3
23.5
12.3
60.0
14.99
T1V5 23.55
30.8
21.25
25.5.
101.1
25.26
T1V6 20.5
29.0
26.5
21.25
97.3
24.31
Sub-Total
131.15 150.8 156.15 126 589.6 24.57
ANALYSIS OF VARIANCE
SOURCE OF
VARIATION
DF
SS
MS
F value
Pr > F
Model
14
1346.28 96.163 2.4 0.0192
Block
3
102.395 34.132 0.85 0.4755
INOC
1
78.541 78.541 1.96ns
0.01708
TRT
5
1106.97 221.394 5.53** 0.0008
INOC*trt
5
58.37 11.674 0.29ns 0.913
Error
33
1321.78 40.054
Corrected Total
47
2688.05
ns-not significant Coefficient of variance-25.85%
**- highly significant
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
30
Table 3. Effect of P. penetrans on weight of fruits (g) of six strawberry cultivars
TREATMENT
REPLICATION
COMBINATION
I II III IV
TOTAL
MEAN
T1V1
72.8 47.7 26.15 57.2
203.85
50.96
TIV2 104.85
91.3
100.6
95.45
392.2
98.05
T1V3
46.55
72.4 51.4 43.7
214.05
53.51
T1V4 54.75
31.55
49.8
56.7
192.8
48.2
T1V5 44.25
35.6
68.35
22
173.2
43.3
T1V6 39.6
38.25
60.3
59.3
197.45
49.36
Sub-Total 362.8
316.8
356.6
334.35
1373.55
57.23
T1V1
52.2
56.25 28.1 18.25
154.8 38.7
TIV2 73.05
88.3
76.65
50.05
288.05
72.01
T1V3
46 18.5 38.95 43.6
147.05
36.76
T1V4 12
51.2
42.35
21.65
127
31.75
T1V5 21.3
18.75
45.2
25.9
11.15
27.79
T1V6 50.8
32.15
23.45
35.2
141.6
35.4
Sub-Total
255.35
265.15 254.7 194.65
869.65 40.4
ANALYSIS OF VARIANCE
SOURCE OF
DF
SS
MS
F value
Pr > F
VARIANCE
Model
14
17163.9 1225.95
5.48
0.0001
Block
3
411.323 137.108
0.61
0.6113
INOC
1
3345.01 3345.01 14.96**
0.0005
TRT
5
13170.5 2634.1 11.78**
0.0001
INOC*trt
5
236.441 47.288 0.21ns 0.9552
Error
33
7378.27
223.584
Corrected Total
47
24541.5
ns-not significant Coefficient of variation- 48.76%
**-highly significant
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
31
Table 4. Effect of P. penetrans on number of fruits of six strawberry cultivars.
TREATMENT
REPLICATION
COMBINATION
I II III IV TOTAL MEAN
T1V1 4.5
3.5
1.5
4.5
14
4
TIV2 12.5
10
10.5
7.5
40.5
10
T1V3 3.5
5.5
4
5.5
18.5
5
T1V4 4.5
3.5
4.5
6
18.5
5
T1V5 4.5
4
5.5
2
16
4
T1V6 5
3.5
4
5
17.5
4
Sub-Total 34.5
30
30
30.5
125
5.33
T1V1 6
7
2
2.5
17.5
4
TIV2 8
3
2
7
20
5
T1V3 4.5
2
3.5
5
15
4
T1V4 1
5
4.5
2.5
13
3
T1V5 4.5
2.5
4.5
3.5
16
4
T1V6 5
3.5
3.5
4
16
4
Sub-Total 29
23
20
24.5
97.5
4
ANALYSIS OF VARIANCE
SOURCE OF
VARIANCE
DF
SS
MS
F value
Pr > F
Model 14
152.323
10.88
4.02
0.0005
Block 3
8.391
2.707
1.03
0.3904
INOC 1
16.922
16.922
6.25**
0.0175
TRT 5
84.151
16.83
6.22**
0.0004
INOC*trt 5
42.859
8.572
3.17*
0.0192
Error 33
85.297
2.706
Corrected Total
47
241.619
*-significant Coefficient of variation- 35.65%
**-highly significant
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
32
Table 5. Effect of P. penetrans on final nematode population in roots
TREATMENT
REPLICATION
COMBINATION
I II
III
TOTAL MEAN
IV
Raw Data
T2V1 4550
6115.88 8711.55
5096
24473.4
6118.36
T2V2 1829
1935
822.9
1370
5956.9
1489.23
T2V3 1354.5
7360
3094
5250
17058.5
4264.63
T2V4 2575.93
4806.4
3209.5
1889.4
12481.2
3120.31
T2V5 1748.25
3775
807.68
3937.5
10268.4
2567.11
T2V6 1735.75
1747.88 20158.5 3253.25
26895.4
6723.85
Sub-total 13793.4
25740.2 36804.1 20796.2
97133.9
4047.24
Transfomed Data
T2V1 3.66
3.79
3.94
3.71
15.09
3.77
T2V2 3.26
3.29
2.92
3.14
12.6
3.15
T2V3 3.13
3.87
3.49
3.72
14.21
3.55
T2V4 3.41
3.68
3.51
3.28
13.88
3.47
T2V5 3.24
3.58
2.91
3.6
13.32
3.33
T2V6 3.24
3.24
4.3
3.51
14.3
3.57
Sub-total 19.95
21.44
21.06
20.95
83.4
20.85
ANALYSIS OF VARIANCE
SOURCE OF
VARIANCE
DF SS MS
Computed
F
Block
3 0.208 0.0609 0.7473
Trt 5
0.919
0.184
1.9810ns
Error 15
1.392
0.093
Corrected Total
23
2.520
ns- not signicant Coeffecient of variation= 8.77%
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
33
Table 6. Effect of P. penetrans on final nematode population in soil.
TREATMENT
REPLICATION
COMBINATION I
II III IV
TOTAL
MEAN
Raw Data
T2V1 64.50
127.50
142.50
112.50
447.00
111.75
T2V2 123.75
393.75
101.25
48.75
667.50
166.88
T2V3 56.25
465.00
266.25
67.50
855.00
213.75
T2V4 56.25
33.75
33.75
30.00
153.75
38.44
T2V5 116.25
172.50
123.75
183.75
596.25
149.06
T2V6 56.25
116.25
67.15
15.00
254.65
63.66
Sub-total 473.25
1308.75 734.65
457.50
2974.15
123.92
Transfomed Data
T2V1 1.81
2.11
2.15
2.05
2.650
2.030
T2V2 2.09
2.60
2.01
1.69
2.824
2.095
T2V3 1.75
2.67
2.43
1.83
2.932
2.168
T2V4 1.75
1.53
1.53
1.48
2.187
1.571
T2V5 2.07
2.24
2.09
2.26
2.775
2.165
T2V6 1.75
2.07
1.83
1.18
2.406
1.705
ANALYSIS OF VARIANCE
SOURCE OF
VARIANCE DF
SS
MS Computed
F
Block 3
1.97
0.22
0.5949
Trt 5
0.67
0.26
8.8936**
Error 15
1.3
0.62
Corrected Total
23
2.91
**-highly significant Coeffecient of variation-21.58%
Effect of Lesion Nematode(Pratylenchus penetrans Filipjev and Shuurmans Stekhoven)on the
Growth and Yield of Six Strawberry Cultivars(Fragaria x ananassa Duch)/ Maricar F. Flores. 2007
Document Outline
- Effect of Lesion Nematode (Pratylenchus
penetrans Filipjev and Shuurmans Stekhoven) on the Growth and Yield of Six Strawberry
Cultivars (Fragaria x ananassa Duch)
- BIBLIOGRAPHY
- ABSTRACT
- TABLE OF CONTENTS
- INTRODUCTION
- REVIEW OF LITERATURE
- MATERIALS AND METHODS
- Source of Nematode Inoculum
- Sterilization of Nematodes
- Inoculation of the Lesion Nematode
- Data Gathered
- RESULTS AND DISCUSSIONS
- Fresh Top Weight
- Fresh Root Weight
- Number of Fruits
- Fruit Weight
- Number of Nematodes in the Roots
- Number of Nematodes in the Soil
- SUMMARY, CONCLUSION AND RECOMMENDATION
- Summary
- Conclusion
- Recommendation
- LITERATURE CITED
- APPENDICES