(MD) Maryland is participating
in an interdisciplinary three-year grower-generated
project entitled "Development and Evaluation of
Management Alternatives for Root Knot Nematodes and
Volunteer Potatoes." Cooperators on the project
include specialists in Field Crops, Entomology,
Nematology and Vegetable Pathology along with the County
Extension Agent, IPM Scout and County Growers. Field and
microplot evaluations initiated in 2000 include the use
of cover crops, soil amendment, alternative economic
crops, and tillage practices to manage root knot nematode
populations. Also examined are currently used rotations,
herbicide use, and tillage practices for impact on
reducing volunteer potatoes.

(MI) The impacts of sub-surface irrigation and tillage
on nematode community structure were investigated in a
corn-soybean rotation system. The water table was
maintained at 50 and 75 cm below soil surface in two
treatments and compared to a drainage tile system, under
both conventional and reduced tillage. The sub-surface
irrigated treatments had a higher percent of total
population of bacterial-feeding nematodes and a lower
percent of plant-parasitic and plant-associated nematode
genera compared to the drainage tile treatment. The 50-cm
water table treatment had a significantly higher percent
of the population as bacterial feeders than the 75-cm
water table system. Conventional tillage resulted in more
genera of nematodes, and a higher percentage of both
bacterial-feeding and plant-associate genera than reduced
tillage. The percent of carnivorous nematodes was higher
in the tilled than the reduced tillage system. In a
22-acre soybean variety trial to evaluate soybean
varieties for resistance to Heterodera glycines, both
Pratylenchus penetrans and Meloidogyne hapla were
commonly associated with various varieties. It appears
that all three species impact bean productivity, and
could be a partial explanation to the issue of why
various soybean cyst nematode resistant varieties perform
well in some locations and not as well in other
locations. A ten-year potato farming system trial
indicated that crop rotation, variety and soil amendments
influenced nematode community structure, soil quality and
crop productivity.

(NY, Geneva) Using perineal pattern analysis, SEM
observations and host range assays, it was determined
that Meloidogyne hapla was the only species of
root-knot nematode currently present in the vegetable
producing areas of New York State. A search was initiated
for resistance to the northern root-knot (Meloidogyne
hapla in onion breeding lines available at Cornell
and Wisconsin as well as large number of Plant
Introduction accessions of onions. To-date, 31 breeding
lines and 54 Plant Introduction accessions have been
tested in the greenhouse in artificially infested soil. A
number of the Plant Introduction accessions evaluated
appeared to be tolerant to this nematode including PI
272255, PI 273212, PI 355047, PI 546115, PI 546174.
Tissue culture systems were developed using onion,
dandelion and tomato root explants for the maintenance
and propagation of M. hapla.

(PA) Four different sources of compost were evaluated
for ability to suppress plant-parasitic nematodes and
weeds in a young apple orchard. Three composts were from
commercial sources and one was a spent mushroom compost.
The treatments consisted of four different compost
sources each applied at two rates. Checks consisted of
plots without compost and either left untreated or
treated once with herbicide. Composts were applied at
depths of 2 inches and 5 inches in late spring. Compost
analysis showed minor variations in pH, mineral content
and other character. Nematode assays showed that the only
plant-parasitic nematode present to any significant level
was Xiphinema americanum. Data showed that
one application of compost was beneficial in controlling
weeds throughout the growing season and performed better
than a single spring herbicide application. The abundance
of weeds was correlated with increases in the dagger
nematode population. Neither compost source nor rate of
application had any significant effect on apple size or
increase in tree growth although the trend suggested that
higher rates of compost were beneficial.

(RI) The efficacy of direct application of
butyric acid was evaluated as a preplant treatment for
nematode management. An assortment of nematode species
and pathogenic fungi were screened for sensitivity to
butyric acid, both contact with the acid and exposure to
its volatiles. To date, 2 days exposure to 8.8 or 88 mg
butyric acid/10 g sand reduced densities of Hoplolaimus,
Tylenchorhynchus, Helicotylenchus, Aphelenchoides (fungivore),
and Heterorhabditis (bacterivore) nematodes.
Volatiles of butyric acid also proved lethal to Tylenchorhynchus
nematodes. The same concentrations (8.8 and 88 mg/10 g
sand) effectively killed sclerotia of Rhizoctonia
solani, a damping-off fungus.

(USDA-SC) Developed
and evaluated a core of the USDA Capsicum
germplasm collection for reaction to M. hapla in
greenhouse tests. The core included 440 PI accessions
that comprised approximately 10 percent of each of the
available Capsicum species or species/varieties
selected from all available geographic origins. None of
the 430 Capsicum spp. accessions evaluated
exhibited high levels of resistance to M. hapla. .
Eleven of the least susceptible (referred to hereafter as
"best") accessions and three of the most
susceptible (referred to as "worst") accessions
were selected for re-evaluation in a replicated
greenhouse test. The 11 best accessions exhibited
intermediate to susceptible reactions to M. hapla
and the three worst accessions were susceptible. Although
five accessions of the best accessions had root gall
severity scores <5.00 (moderately resistant
reactions), the reproductive indices for these accessions
ranged from 8.3 to 31.5, which indicates that the
accessions were susceptible. The next step in searching
for resistance to M. hapla would be to evaluate
the entire Capsicum spp. collection.

(WVA) A
large farming systems trial was initiated to evaluate
transition methods for conversion from conventional to
organic farming practices. A vegetable crop trial is
underway evaluating a high input, compost intensive
management system versus a low-input system that relies
on green manures and cover crops. In addition, earthworm
densities were monitored. Earthworm species identified
included Aporectodea caligenosa and Lumbricus
terrestris and population densities of both
species tended to be greater in compost amended plots
than unamended plots.

(NY, Geneva) A replicated
field test was conducted to determine the efficacy of a
drench application of abamectin (Novartis Agri-Mek, 0.15
EC; fermentation products of Streptomyces avermitilis)
against M. hapla on tomato at rates of 8 and 16
oz/A (100 ml water suspension/plant). Severe incidence
and damage by M. hapla was observed on tomato in
this test. Agri-Mek exhibited only limited activity
against M. hapla in this test.

(USDA, MD) 1) Rhizosphere bacteria were tested in
vitro for production of compounds inhibitory to
nematodes. A number of the isolates suppressed nematode
egg hatch or juvenile mobility; 2) isolated and
identified active compounds from a nematode-associated
fungus; 3) the gelatinous matrix of root-knot nematode
was studied as a structure for inhibiting growth of
bacteria and fungi on nematode eggs.

(FL) Pasteuria
penetrans cannot be cultivated in vitro and
enumerated by traditional bacteriological methods;
therefore, an accurate and efficient immunoassay to
quantify spore populations was sought to enhance field
research and development of Pasteuria as a biocontrol
agent. A monoclonal antibody (MAb) produced against whole
spores was shown to bind a putative glycan epitope
present as a component of the spore envelope. Following
SDS-PAGE of nematode cuticle extracts and immunoblotting
with spore extracts and the MAb as probes, these
glycopeptides were shown to bind to discrete polypeptides
derived from the nematode cuticle. Thus the MAb detects
an epitope of adhesins that are involved in the
attachment of Pasteuria endospores to the nematode
cuticle as a prerequisite to the infection process. An
indirect amplification ELISA was developed to quantify
spore adhesins in a soil matrix. Linear regression
analysis of spore concentration versus signal produced
line fits of 0.98 and indicated a minimum detection limit
of # 3000 spores/g of soil.
Western blot profiles of soil-extracted antigen were the
same as those provided by extracts of purified
endospores, confirming that the ELISA detects Pasteuria
antigens (adhesins) in soil extracts containing native
endospores. The MAb did not detect antigens on cells or
endospores derived from a number of endospore-forming
bacteria cultured from test soils. This establishes the
MAb as a definitive probe to detect adhesins as virulence
determinants on Pasteuria endospores in soil. This
sensitive quantitative immunoassay can be applied as a
tool for evaluating chemical and biological measures
required for control of root-knot nematodes.

(MI) Twenty-two LTER (Long-Term Ecological Research)
plots at the Kellogg Biological Research Station were
surveyed for Pasteuria penetrans during the summer
of 2000. The sites surveyed included old-field succession
(>30 years since the last disturbance), natural
succession (13 years since last disturbance), moderately
disturbed (mowed annually) and highly disturbed (annual
tillage) plots. P. penetrans was detected in 77%
of the sites. The incidence of occurrence was 1.07% (98
of 9,183 specimens). Although it was found primarily
associated with tylenchoid parasites of plants, it was
also found attached to both fungivores and bacterivores.
The incidence of occurrence of P. penetrans appeared
to be related to the extent of ecosystem disturbance. It
was most common in the highly disturbed ecosystems and
least common in old fields that had not been disturbed
for more than 30 years. Significant progress is being
made on producing 16S sequence data for the KBS LTER
strains of P. penetrans. The KBS LTER site will
also be used for evaluation of molecular probes specific
for isolates of Pasteuria. Soils from 15 Michigan
soybean fields were analyzed for occurrence of additional
parasites of Heterodera glycines second-stage
juveniles. All sites were infested with H. glycines. The
procedure consisted of microscopic observation followed
by confirmation on potato dextrose agar. The observations
were made by Dr. Senyu Chen at the University of
Minnesota. Hirsutella spp. were recovered from 47%
of the sites. Pasteuria was not detected in the
soils from these sites.

(NY, Ithaca) A survey for nematodes infected with Pasteuria-species
in New York detected infected stylet-bearing
nematodes from three different genera (Tylenchorhynchus
spp., Tylenchus spp., Meloidogyne sp.).
Also detected in this survey were infected free-living
bacteriophagous nematodes from two different genera: (Cephalobus
sp. and Eucephalobus sp.). The species have
not been confirmed.

(MA) Twenty-one soil samples received from putting
greens for routine nematode assays were examined for Pasteuria-infected
Tylenchorhynchus nematodes. All of the Tylenchorhynchus
in each soil assay were examined. Pasteuria on
other nematodes were noted but not quantified. All 21
samples had Pasteuria-infected Tylenchorhynchus.
On average, 26% of Tylenchorhynchus juveniles were
infected (0-82%); 40% of males (0-83%) and 40% of females
(0-89%). A severity index (SI) was also calculated (total
Pasteuria cells visible on cuticle divided by the
total number of Tylenchorhynchus in the sample).
Average SI for juveniles was 1 (0-2.9), females, 4
(0-10.6), and males, 3.6 (0-14.4). An additional putting
green was comprehensively sampled (20 soil cores assayed
separately, 2934 Tylenchorhynchus). Juveniles had
statistically lower incidence of infection (28.8%) than
males (64.45%) or females (56.66%). SI for juveniles,
males and females was 1.0,1.94 and 1.25 respectively.
Both Tylenchorhynchus and Pasteuria
populations had a clumped distribution in the
putting greens. Other nematodes with Pasteuria
included Helicotylenchus, Hoplolaimus and Meloidogyne.
A survey of a golf course in Rochester, New York was also
conducted. The property had two 18-hole courses.
Approximately 5 years ago, 18 greens (east course) were
fumigated with methyl bromide; the 18 greens of the west
course were not treated. Newly established turf on the
fumigated greens responded well and developed a deep root
system. In May 1999, assays were carried out at the
University of Massachusetts on 10 greens from the east
course and 3 greens from the west Course. The May 12
assay was carried out mostly on east course greens
because they were in bad condition and the superintendent
requested the assay. Three healthy greens from the west
course were included for comparison. Green 4, which had a
high population of root-knot was selected for a
fenamiphos-timing study which was carried out in 1999 and
2000. During this time, 3 greens from the east course and
3 greens from the west course were monitored for
root-knot activity. Root-knot nematode populations
appeared to be higher in the east course versus the west
course except in January and March. A possible
explanation for the differences in nematode populations
between the two courses is that natural enemies including
some of the Pasteuria population were destroyed by
the fumigation.

Obj. 2.2) Determine the survivability and host
preference of isolates of Pasteuria
spp. from different geographic regions.

(NY, Ithaca) Preliminary
setup of an in vitro model system to study Pasteuria-like
parasites of nematodes: A search within the Rhabditida
(especially Family Cephalobidae) resulted in the
discovery of a Pasteuria-like bacterium infecting Cephalobus
and Eucephalobus spp. (subfamily Cephalobinae).
Endospores from 10 nematodes were saved. In vitro
cultures of Cephalobus and Eucephalobus
have been initiated on modified media. Mutants that do
not allow attachment and mutants that allow attachment
but not infection will be generated and selected.
Cultures of two species from subfamily Acrobelinae (viz. Zeldia
punctata and Acrobeloides amurensis) have also
been initiated. We recently inoculated Cephalobus nematodes
in vitro with the first batch of endospores collected and
are currently building up Pasteuria-nematode
cultures. Observation of both infected males and females
(Cephalobus and Eucephalobus) suggests
factors required for endospore development may not be
sex-specific. Requirements for endospore production may
be confined to baseline components or conditions in the
pseudocoelomic fluid that are common to all nematode
species.

(MD) Once plant evaluations in Objective 2.3 indicate
the development of efficient methodology, populations of Meloidogyne
spp. will be established and maintained in greenhouse
and/or laboratory culture in cooperative studies of
multistate researchers involving Pasteuria penetrans. Space
allocations have been established and materials and
methods are in preparation to conduct survivability and
host preference studies with regional cooperation.

Obj. 2.3) Evaluate different crops and
methods for growing Pasteuria penetrans.

(MD) Various plants will be evaluated for production
of P. penetrans endospores using soil
moisture control. Plants currently in evaluation for root
growth and overall cultural manageability include Rutgers
tomato, and Ascanthus and Tradescantia (herbaceous
perennials). Additional hosts will be tested as acquired.

(CT) Meloidogyne hapla can be
spread in bare-root herbaceous perennial propagation
material and may be difficult to control once established
in new fields or in the landscape. Root pruning of
bare-root plants was previously demonstrated to reduce
spread and establishment of M. hapla. Planting M.
hapla-resistant plants such as Rudbeckia and Aster
into pots infested with M. hapla populations
virtually eliminated the nematodes after 2-6 months of
growth, demonstrating the potential of integrating
sanitation and resistance for management of M. hapla
in perennials.

(MD) Survey sampling for nematode evaluations of
fields using potato rotations is currently underway. One
approach to reduce the survival of volunteer potato
tubers is the installment of a hydraulic or chain-driven
chopper situated at rear end of the harvester to cut the
refuse and tubers into finer pieces. The rationale is
that the smaller pieces of tuber will be more prone to
desiccation and rots than whole tubers. Subsequent
reductions in volunteer growth should reduce potential
reservoirs for disease pathogens (i.e late blight) and
CPB recruitment, as well as hosts for nematodes.

(MI) The technologies of precision agriculture are
being evaluated in relation to crop productivity,
economics, nematode management, soil microbial
populations, and soil quality parameters in both potato
and soybean systems. Pratylenchus penetrans, Verticillum
dahliae, potato early-die risk and soil quality
characteristics for a 62-acre potato field was
geopositioned on a one-acre grid basis. A replicated
nematode management trial was designed using three
early-die risk levels and three nematode management
levels. The Michigan State University, Diagnostic
Services Potato Early-Die Risk Matrix was used as the
basis for the experimental design.

(NY, Geneva) Limited information is available on the
pathology and damage of the lesion nematode (Pratylenchus
spp.) to onions. A replicated test in field
microplots was established at the Geneva Station to
assess the damage threshold density of this nematode to
onion. The initial densities established were 0, 1, 2, 4,
8, and 16 nematodes/cc soil. The effectiveness of Vydate
application against this nematode is also been assessed
in microplots and in heavily infested fields. Data
collection and analysis are still in-progress. A
collaborative project titled "Farm ecosystem and
management factors contributing to pest suppression on
organic and conventional vegetable farms" was funded
by NE-SARE program (2000-2002) to multidisciplinary
research and extension colleagues at Cornell. Potatoes
and winter squash are the primary vegetables on the
selected farms. Nematode number and density are been
determined at planting and harvest time on the 10
selected farms (5 organic and 5 conventional). In
addition, soil suppressiveness to root pathogens is also
being determined at harvest. Data collection and analysis
is on-going (NY, Geneva). A multidisciplinary project
titled "A partnership among eastern US carrot
stakeholders to develop and implement IPM" was
funded to Michigan State University in collaboration with
Wisconsin, New Jersey and New York. Management options
against the northern root-knot nematode is among the
contributions to be researched in New York. Initial
demonstration trials to be conducted in collaboration
with commercial growers will focus on the use of
rotational and cover crops, identified damage threshold
levels, and selected nematicides. Identification of
resistant carrot germplasm, evaluation of promising
biological control organisms, and assessing the efficacy
of natural products will be initially conducted in
greenhouse, field microplots and/or experimental fields.
(PA) Evaluation of green manure as a preplant treatment
for replanted orchards: First year activities: An
old cherry orchard with a history of tomato ringspot
virus was removed and subdivided into nine plots (three
treatments at three replicates each). The treatments
included: soil fumigation (Telone II), green manure
(Rapeseed cv. Dwarf Essex) and fallow. Nematode assays
were taken prior to initiating the project. Treatment of
orchard replant sites with Telone II soil fumigant
reduced all plant-parasitic nematode populations to
nearly undetectable levels. Rapeseed green manure
treatments reduced dagger and lesion nematode populations
but not as effectively as soil fumigation. Rapeseed green
manure had no effect on the spiral nematode population
although this nematode is not known to cause problems on
fruit trees. Practices used to prepare orchard replant
sites may affect soil characteristics such as compaction,
organic matter content and others in subtle ways. The
combined effect may affect tree establishment, vigor and
early yield. In subsequent years, data will be collected
on tree growth and yield along with nematode population
development.

(WVA) One unique finding of this research was that
mulch (plastic or straw) does not prevent disease,
rather, it was associated with increased disease. Mulch
is promoted as a cultural practice for prevention of
vegetable diseases by reducing soil splashing onto
foliage thereby inhibiting the spread of inoculum. In the
case of tomato diseases, particularly early blight, the
use of mulch was associated with increased disease.

(CT) Studies on the
interaction of the fungal and nematode pathogens in
strawberry black root rot will help to maximize sampling
to best determine if nematodes are present and involved
in black root rot, the contribution of the nematode to
disease, and may help to manage the disease complex. The
identification and use of rotation crops that reduce both
pathogen populations in soil will assist in the
development of nonchemical controls of black root rot of
strawberry.

(CT) Early dying of potato, also caused by a pathogen
complex including Verticillium and Pratylenchus,
is a major limiting factor of potato production and
is extremely difficult to control. The potential of
disease management by rotation, green manuring or organic
matter amendments would be important both in potato
production and the understanding of how soil ecology
influences pathogens and disease development.

(FL) The MAb has been established as a definitive
probe to detect adhesins as virulence determinants on Pasteuria
endospores in soil. This sensitive quantitative
immunoassay can be applied as a tool for evaluating
chemical and biological measures required for control of
root-knot nematodes.

(MD) The evaluation of rotational crops, organic
amendments and host crop genetics on nematode community
structure, and demonstration of their economic benefits,
will identify alternative tactics for reducing pesticide
use, lowering control costs and crop losses, and provide
a sustainable strategy for managing nematodes in
vegetable and field crops.

(MI) The technology of precision agriculture appears
to have excellent potential for use in management of
plant-parasitic nematodes and the potato early-die
disease complex .The data indicate that the techniques of
precision agriculture had the potential to increase 2000
net profit at this site by $304 per acre.

(MA) Demonstration that natural enemies for biological
control, such as Pasteuria, may be destroyed by
fumigation.

(NY, Geneva) Assessing the genetic and pathological
characteristics of nematode populations, such as those
reported here for Meloidogyne hapla, is critical
for identifying resistant crop germplasm, designing
effective crop rotations, and developing diagnostic
tools. Determining threshold damage level, identifying
resistant cultivars, and searching for effective natural
products against nematodes are important for the
development of IPM programs against plant-parasitic
nematodes. Documenting the impact of management options
on nematodes and the validation of developed IPM programs
in commercial fields and in collaboration with growers
are much needed for the promotion of sustainable nematode
management programs.

(NY, Ithaca) Discovery of Pasteuria on as yet
unidentified root knot and free-living nematodes. Pasteuria
was found not to digest organ systems of the nematode
host. Though Pasteuria penetrans is a very
promising biocontrol agent for certain plant parasitic
nematodes, the nature of host preference is not
understood. Current findings about the nature of the
nematode and bacterial surfaces will contribute to our
understanding of Pasteuria attachment, infection,
and requirements for endospore development and will
facilitate strain enhancement and development of
efficient mass culture systems for Pasteuria.

(PA) Natural
products, green manures and rotation crops can be useful
tools for nematode management in fruit crops. These
practices can be used to develop IPM and
organic production programs with reduced use
of synthetic pesticides.

(RI) Short chain fatty acids, formed from the
fermentation of organic compounds in the soil, are
readily oxidized to carbon dioxide and water by soil
microorganisms. Published experiments have demonstrated
the nematicidal properties of organic acids, with butyric
acid being the most effective. We have confirmed this
effect in golf course soil. Butyric acid holds promise as
a biorational alternative to synthetic fumigants.

(USDA , MD) Rhizosphere bacteria possessing an ability
to colonize crop plant roots have the potential to be
useful biocontrol agents for plant-parasitic nematodes. In
vitro assays followed by growth chamber and
greenhouse tests aid in determining which microbes
demonstrate activity against nematodes. Application of
active natural compounds produced by microbes eliminates
the need to be concerned about packaging, shipping, and
shelf-life of live organisms. Studies of the gelatinous
matrix and egg masses contribute knowledge about
interactions between nematodes and microbes.

(USDA , SC) The northern root-knot nematode causes
serious damage to pepper (Capsicum spp.) in the
U.S. and worldwide. The development of cultivars with
genetic resistance to root knot nematodes is the most
efficient and environmentally benign way of controlling
this production problem. Host resistance also provides
the most viable and easily implemented alternative to the
use of methyl bromide soil fumigation to control
root-knot nematodes. Because there are no sweet or hot
pepper cultivars with resistance to M. hapla
available to pepper growers, it is important to search
for resistance in available pepper germplasm collections,
such as the USDA pepper germplasm collection.

(CT) The effects of rotation crops
on black root rot pathogens in soil will continue to be
evaluated. The effects of plant residues on pathogens
will be distinguished from the effects of plant growth.
Saia oats, sorgho-sudangrass, canola and Polynema
marigold and plants in the Asteraceae will be examined.
The effects of resistant perennial ornamental plants and
incorporating plant residues on root-knot nematodes will
be determined.

(CT) The effects of rotation and antagonistic crops on
potato early dying caused by Verticillium dahliae
and P. penetrans will continue to be investigated
in microplots. The effects of a single season of rotation
crops in 1999 on early dying symptom development will be
determined in 2000.

(FL) Studies for the next year will seek to develop
bivalent F(ab)₂ and monovalent F(ab)
forms of the IgM MAb to allow a better definition of the
epitope recognized by the MAb. Recombinant antibodies
bearing the Fv region of the MAb will be engineered and
expressed in E. coli to develop alternative
reagents for field tests to detect P. penetrans.

(MD) Continuation of field and microplot evaluations,
and expansion of host selection for maintenance and
increase of Meloidogyne and Pasteuria
cultures.

(MA) Stunt nematodes: Six greens have been
selected that have a range of Pasteuria-infected
stunt nematodes. Two greens have low (3.4 and 8.3%), two
have medium (14 and 22%), and two have high levels of
infection (70% each). On one each of the low, medium and
high sites, Nemacur-treated and non-treated plots (six
replications of each) will be established. On each green,
composite samples will be taken every 5 weeks from May
until November to assess the population dynamics of Pasteuria
and stunt nematodes. Root-knot nematodes: Six greens have
been selected that represent a range of root-knot
populations and Pasteuria infections. These greens
will be sampled when root-knot juveniles are most
prevalent in the soil, September through June. Sampling
frequency will depend on weather (frozen ground)
conditions. Nemacur will be applied to two of the root
knot infested greens. These greens will have six treated
and six untreated plots.

(NY, Geneva) Onion Plant Introduction accessions
tested and exhibiting tolerance to the northern root-knot
nematode (Meloidogyne hapla) will be re-evaluated
in the greenhouse and in field microplots. Tests will
identify and will characterize suppressive soils against
major plant-parasitic nematodes to vegetables in New
York. Assess the effect of the inclusion of appropriate
crops (rotational or antagonistic cover crops) in
suppressing nematode populations and their damage to
vegetables. Research efforts will be continued to
identify resistance factor(s) against the northern
root-knot nematode in onions and other vegetables.
Efficacy of natural products and promising biological
control organisms will be determined against root knot
and lesion nematodes on vegetable crops. IPM programs
will be designed and will be evaluated against the root
knot and lesion nematodes on carrots, onions and other
vegetables grown in New York.

(NY, Ithaca) In vitro method for maintaining
free-living nematodes infected with Pasteuria will
be refined to facilitate studies of host-parasite
interactions and requirements for endospore development.
Studies will determine the role (if any) of sialylated
residues in the epicuticle of "stripped" Meloidogyne
incognita second-stage juveniles (J2).
"Stripped" J2 refers to J2 with surface coat
removed. Anti-P20 IgM will be tested on
"stripped" Mi J2. The use of differential mass
spectrometry will be explored to identify specific
cuticular epitopes involved in the attachment of P.
penetrans endospores to the nematode surface.

(PA) Field testing green manure treatments of rapeseed
and other cover crops for ability to control Xiphinema
will be continued as well as evaluation of different
preplant treatments on orchard establishment and early
crop yields. Research on the biology and phylogenetic
relationships of Xiphinema americanum - group
nematodes, including virus associations, will continue.

(RI) Screening nematode species and pathogenic fungi
for sensitivity to butyric acid will continue. Based on
those results, a greenhouse trials will be conducted to
evaluate the effectiveness of butyric acid as a preplant
treatment for strawberries. Parasites and pathogens of
interest on strawberries include Pratylenchus
penetrans, Meloidogyne hapla, Phytophthora fragariae,
Pythium, Rhizoctonia solani, Fusarium oxysporum, and Verticillium
dahliae. The persistence of butyric acid in soil will
be quantified.

(USDA, MD) Studies will continue on fungi and
on rhizosphere bacteria to determine whether selected
microbes produce nematode-antagonistic compounds.
Promising natural compounds and/or live agents will be
investigated to determine whether they are useful for
management of plant-parasitic nematodes.

(WVA) Population density and activity of nematode
trapping fungi will be monitored in apple blocks with and
without ground cover of endophyte-infected and
endophyte-free fescue. Research will also continue in an
effort to determine the mechanism of suppressiveness of
endophyte infected fescues and to determine how best to
integrate this rotation crop with orchard management
systems. Farming systems research to compare compost
amendments and rotations in organic vegetable and field
crop production systems will be continued. Soil
suppressiveness to nematodes and population dynamics of
indigenous biocontrol agents will be compared in sites
receiving compost amendments versus grass-legume
rotations during a three-year transition phase from
conventional to organic farming systems.

(USDA, SC) Evaluate the next 25% of USDA pepper (Capsicum
spp.) collection for resistance to northern root-knot
nematode (M. hapla) and determine heat stability
of N gene (for root-knot nematode resistance) in
heterozygous pepper genotypes.