NE171: Biologically Based IPM Systems for Management of Plant-Parasitic Nematodes
Annual/Termination Reports (SAES-422): [12/18/2000] [12/10/2001] [12/04/2002] [11/25/2003] [12/09/2004]
Date of Annual Report: 12/18/2000
Report Information:
Participants:
URL: Copy of participant list
Brief Summary of Minutes of Annual Meeting:
URL: Copy of minutes
Accomplishments:
Intended outcomes and potential impacts (based on projectmilestones):
Objective 1: Evaluate the effects of rotational
crops, organic amendments and host crop genetics on nematode
community structure.
Complementary or collaborative studies to assess the impact of
rotation and cover crops on plant-parasitic nematode populations
and nematode community structure:
- Milestone 2000: Establish a low soil
volume bioassay to evaluate nematode antagonistic crops.
developed (manuscript in preparation, PA) and will be
used in further studies to evaluate the toxicity of green
or freeze-dried plant extracts on a variety of plant
parasitic nematodes using soils and nematodes supplied by
cooperators in CT, MA, NY, and WV.
- Milestone 2000: Identify and evaluate
nematode resistant or tolerant varieties for inclusion in
an integrated management program.
early dying of potato caused by Verticillium dahliae
and P. penetrans was investigated in field
microplots infested with both pathogens. Polynema
marigold rotation crops significantly reduced the AUDPC
for early dying symptoms and increased total, and
marketable tuber yields.
(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.
Objective 2: Characterization of biological control
agents for suppression of plant-parasitic nematodes.
Sardanelli (UMCP) laboratories continue to refine
previously developed soil moisture control system
materials and methods (Sardanelli and Kenworthy 1997) for
ongoing evaluations of various fungi (Verticillium,
Fusarium, Cladosporium) and their potential use as
biocontrol agents.
(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.
Obj. 2.1) Survey plant-pathogenic nematodes for
occurrence of Pasteuria spp.
- Milestone 2000: Conduct a workshop
for all group members to present protocols for Pasteuria
penetrans recognition, research and surveys.
regional meeting of the new project to teach members how
to recognize Pasteuria spp. on different species
of plant-parasitic nematodes. A pamphlet will be prepared
and distributed to each member of the technical committee
for use as a guide for proper handling of Pasteuria
spp. The goal of the workshop and pamphlet was to ensure
that all members follow prescribed methods in documenting
the occurrence of Pasteuria on plant-parasitic
nematodes in northern regions of the United States.
Survey plant-pathogenic nematodes for occurrence of Pasteuria
spp.
attached to males and juveniles of the turf cyst nematode
Heterodera iri in samples from a commercial golf
course. The course superintendent indicated that the
green had previously been damaged by high nematode
densities, but had recently recovered. Clean juveniles
added to soil and recovered by pie pan extraction had a
low incidence of infection. Infested soil was inoculated
with H. iri cysts and planted with Penncross
bentgrass to increase the parasite population.
(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.
Objective 3: Comparison and evaluation
of IPM system management of plant-parasitic nematodes based on
crop rotation, organic amendments, host crop resistance and
biological control agents.
- Milestone 2000: Initiate collaborative
rotation and cover crop system research in field plots
and microplots in multiple states.
perennial strawberry caused by Rhizoctonia fragariae
and the lesion nematode Pratylenchus penetrans. Rhizoctonia
infection of structural and feeder roots increases during
secondary growth when the cortex is cut off by suberized
tissues, during harvest, and when lesion nematodes are
present in roots. The effects of inundative releases of
entomopathogenic Steinernema carpocapsae and S.
feltiae infective juveniles on lesion nematode (Pratylenchus
penetrans) populations in strawberry roots were
determined in field microplots and small plots.
Application of entomopathogenic Steinernema
carpocapsae and S. feltiae nematodes did not
affect populations of migratory endoparasitic lesion
nematodes in strawberry. We were able to demonstrate
reduced mobility associated with dead insect nematodes,
and this effect was greater in water than in soil.
Bacteria associated with the insect parasites may cause
nematode suppression, but the suppression appears to be
temporary.
(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.
Deliverables (stakeholder items):
densities in soils infested with a history of black root
rot were incorporated into a strawberry economics model
developed by Alison DeMarree & Regina Rieckenberg at
Cornell University. Initial lesion nematode densities as
low as 12 per g root resulted in an 11% loss over 4 years
and densities as high as 125 per g root resulted in 100%
loss in profit over the same time.
(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.
Plans for the coming year:
Connecticut will be tested for ability to parasitize
cyst, root knot or lesion nematodes in greenhouse and
laboratory assays.
(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.
Impact Statements:
Date of Annual Report: 12/10/2001
Report Information:
Participants:
- url
URL: Copy of participant list
Brief Summary of Minutes of Annual Meeting:
URL: Copy of minutes
Accomplishments:
NE171 Accomplishments and Impacts
Impact Statements:
Date of Annual Report: 12/04/2002
Report Information:
Participants:
- Louis Magnarelli, Administrative Advisor Connecticut Agricultural Experiment Stn.
- George S. Abawi * Cornell University, Geneva, NY
- George W. Bird * Michigan State University
- Don W. Dickson * University of Florida
- John M. Halbrendt * Penn State University
- Jim Kotcon * West Virginia University
- Jim LaMondia * Connecticut Agricultural Experiment Stn
- Susan L. Meyer USDA, ARS, Beltsville, MD
- James F. Preston University of Florida
- Nathaniel A. Mitkowski * University of Rhode Island
- Sandra Sardanelli * University of Maryland
- Judy A. Thies *, Secretary USDA, ARS, Charleston, SC
- Robert L. Wick * University of Massachusetts
- Janet Chen Cornell University
- Bess Dicklow University of Massachusetts
- J. Hunter Cornell University
- J. W. Ludwig Cornell University
- Karen Snover Cornell University
- Fred Warner Michigan State University
Brief Summary of Minutes of Annual Meeting:
Action Items/Assigned Responsibility/Deadlines/Target DatesThe participants introduced themselves. The minutes of the 2001 Annual Research Technical Committee meeting were approved for posting on the NE-171 website. George Abawi, Local Arrangements, welcomed everyone to New York.
Lou Magnarelli distributed a timetable for rewriting the NE-171 Project and discussed procedures for rewriting. A brief discussion ensued about the potential rewrite or revision of the project.
Jim LaMondia will be the Chair of the Committee for the next two years and Judy Thies will be the Chair-Elect. Nathan Mitkowski volunteered to be the next Secretary (replacing Judy Thies) and he was unanimously approved for the position by the Committee.
Judy Thies, Jim LaMondia, and Don Dickson were nominated and unanimously approved to serve on the writing committee. Judy Thies will chair the committee.
George Bird presented an excellent workshop titled The Identification of Free-Living Nematodes. The topic of the workshop was highly relevant to the NE-171 Committee because the first objective of the NE-171 project is to evaluate the effects of rotational crops, organic amendments and host crop genetics on nematode community structure, which includes free-living nematodes. George Abawi had arranged for a local microscope company to provide microscopes and video equipment for the workshop.
The 2003 meeting will be held in Rhode Island and Nathan Mitkowski will be the Local Arrangements Chair.
Summary of Discussions (Append distributed information):
Project members and collaborators from each of the states and USDA, ARS reported on their research during the previous year. Progress reports distributed during the meeting can be obtained from Lou Magnarelli, Sandra Sardanelli, or the respective project members.
The project milestones were reviewed and a consensus was reached that the current milestones have been met.
The theme and objectives for the new Project were discussed. Topics discussed included the role of nematode communities in soil health, sustainable soil management, and alternative strategies for managing nematodes.
Between Meeting Information and Exchange/Development Information:
The meeting report and minutes will be prepared by Jim LaMondia and Judy Thies, respectively, and sent electronically to Lou Magnarelli, Administrative Advisor, for approval. Jim LaMondia will post the approved report and minutes on the project web site.
The writing committee (Jim LaMondia, Don Dickson, and Judy Thies) will contact potential reviewers for the Project proposal in November and December 2002. Names, addresses, fax, and telephone numbers of at least 6 reviewers will be provided to Lou Magnarelli. The writing committee will also prepare and submit a request to write a proposal to Lou Magnarelli (for approval), who will then submit the approved request to the Directors Multistate Activities Committee for review in February or March 2003. After approval to write the project proposal is received, the writing committee will develop the proposal using input from NE-171 members, a CRIS search will be done, and the proposal will be distributed to NE-171 members for review (April August 2003). Lou Magnarelli will electronically submit the project proposal to National Information Management and Support System (NIMSS) and reviewers and notify all Directors to enter scientists (Appendix E). NE-171 members will ask their Deans or Directors to complete Appendix E electronically. NE-171 members will discuss final changes for new project at the annual meeting in October 2003.
Accomplishments:
Objective 1: Evaluate the effects of rotational crops, organic amendments and host crop genetics on nematode community structure.Complementary or collaborative studies to assess the impact of rotation and cover crops on plant-parasitic nematode populations and nematode community structure:
Dr. George Bird, Nematologist at Michigan State Univ., conducted a successful half-day workshop on the Characteristics of the Orders and Selected Taxa of the Nematoda at the 2002 NE-171 Technical Committee Meeting in Geneva, NY. The identification of free-living nematodes will assist researchers evaluating the impact of nematode management tactics on nematode community structure in soil. Dr. Bird has prepared chapters on ‘nematode biology and management‘ & ‘nematodes and soil quality‘ in two interdisciplinary MSUE Bulletins: Michigan Field Crop Ecology E-2646, and Michigan Field Crop Pest Ecology and Management E-2704.
Milestone 2002: Initiate research to determine the mechanism of nematode antagonism in rotation and cover crops.
(MD) An interdisciplinary IPMSARE team is now into the third year of a MD grower-generated project entitled Development and Evaluation of Management Alternatives for Root Knot Nematodes and Volunteer Potatoes. Fields in Maryland (MD) cropped repeatedly to vegetables have experienced significant losses due to root knot nematodes (RKN), Meloidogyne spp. Maryland growers have expressed concern over sporadic but widespread surges of lesion nematode populations (Pratylenchus spp.), often associated with RKN from symptomatic fields. Both RKN and lesion nematodes have broad host ranges. Cooperators on the project include specialists in Field Crops, Entomology, Nematology and Vegetable Pathology along with the Dorchester County Extension Agent, IPM Scout and Dorchester County Growers. In this project, using a combination of on-farm (natural infestations) and micro-plot (artificially infested) experiments, sustainable management alternatives and their effect(s) on the plant-parasitic nematodes are being evaluated. Of all seasonal samplings and RKN life-stage evaluations (including root gall indices and root/egg harvest), Fall soil J2 sampling is showing the greatest significance as an indicator for detection and population evaluation purposes in MD.
7Milestone 2002: Evaluate the impact of rotation and cover crops and soil amendments on nematode populations.
(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. Dagger nematode population levels were extremely variable and only very large differences were shown to be statistically different. Nevertheless, plots treated with five inches of mushroom compost consistently had the lowest nematode numbers and mushroom compost applied at two inches also showed relatively low nematode numbers throughout the study. Although no conclusions can be drawn, these data hint at the possibility that mushroom compost is suppressive to dagger nematodes. Likely candidates would be either the chemical composition or antagonistic microflora.
(PA) Treatment of orchard replant sites with Telone II soil fumigant reduced all plant-parasitic nematode populations to nearly undetectable levels. Rapeseed green manure treatments also reduced dagger and lesion nematodes but not as effectively as fumigation. However, in addition to nematode suppression, the rotation also provided an opportunity to bring broadleaf weeds under control, a major concern for the prevention of Peach Stem Pitting Disease. Tree growth data indicate that tree performance is nearly the same under all preplant treatments. Another year of observation is needed to determine if stem-pitting is confirmed in untreated fallow plots.
(NY) Onion germplasm consisting of >50 accessions of A. fistulosum, two sources of A. roylei, and several A. cepa were evaluated against M. hapla. All the materials evaluated were susceptible, but several accessions were found to be higher in tolerance than the commercial varieties in the tests. A cross of A. roylei and A. cepa (provided by Dr. Martha Mutchler at Cornell) was among the best materials tested.
(NY) Eight selected soybean cultivars were found to be good hosts to Pratylenchus penetrans. Incorporation of these cultivars as green manures 4 weeks before planting did not reduce the number of lesion nematodes in snap bean roots.
Objective 2: Characterization of biological control agents for suppression of plant-parasitic nematodes.
(USDA-ARS) Strains of rhizosphere-inhabiting bacteria, known to act against certain soilborne plant-pathogenic fungi, were tested in the greenhouse for ability to suppress root-knot nematode populations on cucumber roots. The greenhouse assay system identified a potentially useful bacterium. This bacterium was tested in the lab to determine whether natural products in culture filtrates suppressed egg hatch and juvenile mobility. A strain of Trichoderma virens was also tested for activity against Meloidogyne incognita on cucumber. Collaborators: Daniel Roberts (USDA ARS Sustainable Agriculture Systems Laboratory, Beltsville).
Obj. 2.1) Survey plant-pathogenic nematodes for occurrence of Pasteuria spp.
(FL) Environmental detection of endospores of Pasteuria spp. Conditions have been defined for the quantification of endospores of Pasteuria spp. using a monoclonal antibody directed against an epitope associated with the parasporal fibers that cover mature endospores. An amplification ELISA assay using biotinylated secondary antibody allows quantification to a minimum of 300 endospores per gram of soil. The assay is not affected by organic matter and is applicable to soils conducive to infestations with plant-parasitic nematodes. The assay has also been used to quantify the level of endospores in root tissues, and should be useful in assessing the potential levels of soil-borne endospores in subsequent plantings. The assay should be useful in assessing the extent to which soils are or may become suppressive for nematode infestations and thereby limit the need for other control measures.
Obj. 2.2) Determine the survivability and host preference of isolates of Pasteuria spp. from different geographic regions.
(MD) Populations of Meloidogyne incognita have been established and are maintained in laboratory, greenhouse and field sites for in preparation for cooperative studies with multistate researchers involving Pasteuria penetrans. Once sufficient inoculum is obtained, the bacterial nematode parasite will be introduced into root-knot nematode-infested microplots in the field. Both the nematode and its parasite will be monitored over time to determine whether the parasite will increase to suppressive levels and whether it will survive the winter season. Cooperating states are FL, MD, and MI.
Obj. 2.3) Evaluate different crops and methods for growing Pasteuria penetrans.
Rutgers tomato and PA136 Bell pepper have been selected as hosts for in house culture of Meloidogyne incognita on the basis of root vigor and overall cultural manageability, and are being grown in a soil moisture control system (Sardanelli and Kenworthy, 1997) and in a standard greenhouse environment. Meloidogyne incognita cultures are being maintained and increased in preparation for Trichoderma evaluations and also for microplot overwintering evaluations and/or production of P. penetrans endospores planned for Florida isolates of Pasteuria penetrans.
Objective 3: Comparison and evaluation of IPM system management of plant-parasitic nematodes based on crop rotation, organic amendments, host crop resistance and biological control agents.
(NY) Assessing the incidence and severity of root-galling on carrots as well as conducting a soil bioassay with lettuce (indicator host) at harvest were highly effective in determining the need for root-knot nematode control on the following crop cycle of carrots or other susceptible hosts.
(NY) A combined in-furrow and foliar spray application of Vydate C-LV increased potato tuber number and weight as well as slightly reduced the number of root-knot nematode in soil and roots. No root-galling symptoms were observed on infected potato roots.
Impact Statements:
- Drs. J. A. LaMondia (CT) and J.M. Halbrendt (PA) and co-investigators were awarded a competitive grant to find alternative methods of nematode control as a part of the Methyl Bromide Transition Program. Collaborative studies from NE-171 enabled these scientists to secure additional funds for further research to help solve immediate stakeholder problems.
- Drs. G.S. Abawi (NY), G.W. Bird (MI), and N.A. Mitkowski (RI) were awarded a competitive grant for research on alternative methods of nematode control as a part of the Methyl Bromide Transition Program. Their collaborative work in NE-171 helped them secure these funds for additional studies to assist stakeholders.
- A workshop conducted during the NE-171 meeting provided specific training for participants to improve their skills on identifying nematodes. This knowledge will assist scientists in the evaluation of impact of nematode management tactics in growers' fields.
- Field studies on mechanisms of nematode antagonism in rotation and cover crops revealed that lesion nematodes from strawberry roots were highest for Dwarf Essex canola and oats. However, the incorporation or removal of shoots had a significant effect on nematode numbers, indicating that plant breakdown products may be nematicidal. Results were shared with vegetable and fruit growers.
- A bioassay technique, using freeze-dried plant material and sand, successfully detected potential nematicidal compounds, which may be useful in future control efforts.
- Application of Telone II as a soil fumigant reduced all plant-parasitic nematode populations to nearly undetectable levels in orchard replant sites. Growers now have a new option for control.
- The identification of root-knot resistant bell pepper cultivars provides growers with economically and environmentally compatible alternatives to the use of methyl bromide and other nematicides to control Meloidogyne incognita.
- Enzyme-linked immunosorbent assays and DNA probes have been developed to detect endospores and vegetative stages of Pasteuria species, an important biocontrol agent of nematodes. These tests improve detection of Pasteuria in field plots and enable more accurate assessments of which soils are or may become suppressive for nematode infestations. Incorporation of these methods into IPM programs should help growers reduce amounts of pesticides used where Pasteuria is active.
Date of Annual Report: 11/25/2003
Report Information:
Participants:
URL: Copy of participant list
Brief Summary of Minutes of Annual Meeting:
URL: Copy of minutes
Accomplishments:
Objective 1: Evaluate the effects of rotational crops, organic amendments and host crop genetics on nematode community structure.Milestone 2003:Integrate plant resistance with rotation crops to predict nematode population decline under integrated management systems. An interdisciplinary IPMSARE team completed a three-year MD grower-generated project entitled Development and Evaluation of Management Alternatives for Root Knot Nematodes and Volunteer Potatoes. This project evaluated on-farm and micro-plot experiments, sustainable management alternatives and their effect(s) on plant-parasitic nematodes. Of all seasonal samplings and Meloidogyne spp life-stages (gall indices and eggs/root), Fall soil J2 sampling was the most accurate indicator for population evaluation.
(PA) Dagger nematodes (Xiphinema americanum) are the most important nematode problem in orchard sites in PA. Nearly 85% of samples contain dagger nematodes, which are usually below 25 per 100 cm3 soil but problematic as virus vectors. Preplant rotations with rapeseed reduce dagger nematodes, but but only after being turned in as a green manure. A bioassay technique using freeze-dried plant material was used to detect the presence of nematicidal compounds in a number of plants.
(CT) In cooperation with PA, the influence of rotation and green manure crops on early dying of potato caused by Verticillium dahliae and P. penetrans was investigated. Pipersudangrass, Rudbeckia hirta, Saia oat, Dwarf Essex canola, Polynema marigold, Haychow sorgho-sudangrass, Pearl Millet 101, Trudan 8 sudangrass, Standard oat, and Kennebec potato were grown. All rotation crops but oat reduced lesion nematodes; Rudbeckia hirta, and Polynema marigold had few or undetectable levels of nematodes.
(NY) Reaction of twelve commercial varieties of potatoes to M. hapla: Damage by the northern root-knot nematode to onion, carrots, lettuce and other susceptible crops is most severe when grown after potatoes, especially on organic soils. Potato is a host for M. hapla, but root-galling symptoms and yield losses have not been observed in New York. Thus, 12 varieties of potatoes were rated for root-galling severity on a scale of 1 (no galling) to 9 (>80% roots with galls). Eggs were extracted. All the potatoes exhibited extensive root-galling on the fine fibrous roots, but not coarse roots.
(NY) Evaluation of twenty-one commercial carrot varieties for resistance to M. hapla: The northern root-knot nematode is a major pathogen of carrots grown in New York. Twenty one carrot varieties were evaluated for M. hapla. Six weeks after inoculation, carrots were rated for root-galling severity, and eggs were extracted from roots. All varieties were susceptible hosts to M. hapla.
(RI) The effect of nematicidal applications of the organic butyric and propionic acids against Meloidogyne hapla and Pratylenchus penetrans was investigated. Concentrations of butyric acid and propionic acid were employed as a preplant nematicidal treatment, in conjunction with an untreated and a Vydate control. Butyric acid acted as a biocide, and nematode control was equivalent to Vydate.
(USDA-ARS SC) Root-knot nematodes (Meloidogyne arenaria, M. incognita, M. javanica and M. hapla) reduce yields of vegetables worldwide. Resistant cultivars of many crops to different root-knot species are not available. There was significant genetic variability within the U.S. PI Citrullus germplasm collection for resistance to M. arenaria race 1. The C. lanatus var. citroides accessions are potential sources for resistance to M. arenaria race 1 in improved watermelon cultivars. Peppers with the N gene for resistance to southern root-knot nematode have been effective in nematode management. A pepper PI with moderate resistance to the northern root-knot nematode M. hapla has been identified and may be a useful management alternative in the Northeast.
Objective 2: Characterization of biological control agents for suppression of plant-parasitic nematodes.
(CT) A possible northern root-knot nematode-suppressive soil was identified. Soils with M. hapla present at high densities for over a decade exhibited a population decrease after being planted to hosts. M. hapla juveniles were exposed to soil for 24 hours and examined microscopically. Pasteuria endospores were present on the cuticles of 60% of the J2, perhaps explaining the reduction in nematodes.
(USDA-ARS) Strains of rhizosphere-inhabiting bacteria, known to act against certain soilborne plant-pathogenic fungi, were tested for ability to suppress root-knot nematodes on cucumber roots. A greenhouse assay system identified a potentially useful bacterium, which was tested in the lab to determine whether natural products in culture filtrates suppressed egg hatch and juvenile mobility. A strain of Trichoderma virens was also tested for activity against Meloidogyne incognita on cucumber. Collaborators: Daniel Roberts (USDA ARS Sustainable Agriculture Systems Laboratory, Beltsville).
(USDA-ARS, FL) Field trials were conducted in Florida to evaluate the effects of tomato and pepper transplants treated with biological control agents and planted into solarized soil on root-knot nematodes, plant growth and yield. Formulations of plant growth-promoting rhizobacteria (PGPR) increased tomato and pepper transplant growth. Transplant vigor and survival in the field were improved by PGPR in both tomato and pepper and on pepper, one PGPR formulation reduced root-knot galling. Yield of pepper was increased with two PGPR. Soil solarization did not control the root-knot nematode on tomato. However, solarization combined with PGPR on pepper produced yields comparable to untreated plants grown in methyl bromide fumigated soil.
(FL) Long-term effects of peanut, Bahiagrass, and weed fallow on the levels of Meloidogyne arenaria race 1 and Pasteuria penetrans were investigated to determine the persistence of P. penetrans after 9 years. A soil test was developed to determine the suppressiveness of P. penetrans to M. arenaria. Over 4 years, the mean number of endospores per J2 and percentage of J2 with endospores increased greatly. Weed fallow plots had the highest percentage of J2 with endospores attached (75%). Bahiagrass and rhizomal peanut had lower percentages (7 and 2%, respectively). When water percolated through soils, most endospores stayed on the top layer of soil. The incidence of the bacterium is related to the density of the peanut root knot nematode.
(WV) Perennial ryegrass lines were inoculated with endophytic Neotyphodium lolii isolates genetically modified to suppress production of specific toxins for nematode suppression. P. scribneri increased on endophyte-free plants, but declined on all endophyte infected plants. Populations on plants where the endophyte was modified by a Lysergyl Peptide Synthetase gene knockout (LPS) were as low as on wild-type endophyte-infected plants. Plants where the endophyte was modified with either a failed LPS gene insert, or with a Di-Methyl Allyll-tryptophan synthetase gene knockout had intermediate populations, suggesting that nematode suppression is not related specifically to ergovaline production.
Obj. 2.1) Survey plant-pathogenic nematodes for occurrence of Pasteuria spp.
(FL) Development of DNA probes for the detection of vegetative stages of Pasteuria spp.is ongoing. Based upon 80% of sequence determined for the sigE gene in P. penetrans, primers were designed for the PCR amplification of this gene in M. arenaria derived from tomato plants. Using Real-Time PCR, the level of infection of M. arenaria by vegetative cells of P. penetrans was determined. An assay is available to complement the immunoassay that detects mature endospores through the recognition of an epitope present only on the mature spores.
Obj. 2.2) Determine the survivability and host preference of isolates of Pasteuria spp. from different geographic regions.
Milestone 2003: Evaluate the winter survival of Pasteuria penetrans in northern states.
(MA) Pasteuria penetrans parasitic on Meloidogyne graminis and Tylenchorhynchus has been found overwintering on turf in golf greens in MA. A correlation between the percent of Pasteuria-encumbered J2 and the density of Meloidogyne graminis J2 was present at high but not low densities. A correlation between Pasteuria- encumbered Tylenchorhynchus spp. and density was evident. In addition, Pasteuria spores appeared to be present on the cuticles of the M. hapla J2 in field microplots that had been exposed to winter conditions in CT. Pasteuria endospores appear to readily survive the winter in CT and MA.
Objective 3: Comparison and evaluation of IPM system management of plant-parasitic nematodes based on crop rotation, organic amendments, host crop resistance and biological control agents.
Efficacy of control products against M. hapla or Pratylenchus penetrans in field microplots. Researchers in MI, NY and RI, funded by the methyl bromide alternative program, was initiated in 2003. In spring 2003, plots were Methyl bromide-fumigated (350 lbs/A, under plastic), treated with Basamid (granular, 350 lbs./A), Vydate L (2,25 gal./A), Fosthiazate (11.5 pts./A), Agri-Mek (16 ozs/A, 2 apps) or an Untreated check. Tomatoes grown in the methyl bromide-treated plots did not exhibit root-galling symptoms and had the lowest number of M. hapla eggs. Root-galling ratings and egg recovery were reduced by Basamid, Fosthiazate, and Vydate. Only methyl bromide increased number and weight of fruit.
(MI) The persistence of Heterodera glycines under various crop rotation and H. glycines sources of resistance were studied at the Greg Mahoney Farm in St. Charles, Michigan in 1995. Soybean yields were greater after three years of corn, three years of clover, or one year of corn followed by two years of a resistant soybean cultivar, compared to yields after five years of continuous susceptible soybeans. There were no differences among the at-harvest nematode densities among any of the systems following a single year of a resistant cultivar. The at-harvest density of H. glycines associated with the mixture of PI 88788, Peking and Kenwood 94 was not different from any of the other systems in 2001.
Assessing the occurrence, damage and need for controlling M. hapla on carrots: The northern root-knot nematode has a wide distribution and causes yield losses to carrots in New York. A collaborative project was started to train carrot and onion growers to index their fields for root-knot. The latter involve collecting appropriate soil samples from fields and conducting a soil bioassay with lettuce for 28-42 days. The need to treat is based on the root-galling severity observed on lettuce roots {for carrots is only an average of >1 gall/root system; a rating of >2 (1-3% of roots galled)} on the 1 to 9 scale. The latter scheme is being compared to the extraction of J2 of M. hapla from soil sample to assess the need to treat.
(WV) The economic returns of low versus high input farming systems for transition to organic practices were comapared for a Market Garden system. Yields of various crops in organic farming systems were generally greater with the high input (with compost) system than in low input (cover crop only) farming systems. Yields were not correlated with any nematode pest, but were related to soil factors such as organic matter content and pH. Although the with compost treatment was highly significant in predicting yields, soil organic matter was not increased, nor was pest density or biocontrol agent activity affected. Leaf petiole nitrate in potato was lower in plots with compost, indicating that this nutrient does not explain crop yields.
Impact Statements:
- Validation of alternative nematode management tactics and demonstration of their economic benefits provides growers with additional tools for reducing pesticide use, lowering control costs and crop losses, reducing human health risk, increasing food safety and providing a more sustainable strategy for managing nematodes in vegetable and field crop rotation.
- Effective nonchemical controls will help to maintain production in the absence of methyl bromide, and enhance economic opportunity in rural communities. For example, the current application of Vydate (up to 4 gal/acre rate) on carrot for nematode control costs growers approximately $250.00 per acre per year. There is a great opportunity to develop a safer alternative to Vydate at a lower cost.
- Training of onion, carrot, and other vegetable growers to conduct their own bioassays for root-knot nematodes will allow targeted nematode management only in fields with damaging nematodes, reducing human health risk, environmental exposure, pesticide residues in food, and reduced production costs. The use of Vydate (up to 4 gal/acre) on carrot costs growers about $250.00 per acre per year.
- Cooperative research on PGPR formulations with Gustafson LLC has resulted in a new commercial product for use on transplanted crops, BioYieldTM, consisting of a formulation of plant growth and yield enhancing bacteria, reducing human health risk, environmental exposure, pesticide residues in food.
- Root-knot nematodes (Meloidogyne spp.) are a major constraint to production of vegetables. Host resistance is the most economical, environmentally benign alternative to methyl bromide. Root-knot nematode resistance conferred by the N gene is effective in field?planted bell pepper and should provide economical and environmentally compatible alternatives to methyl bromide and other nematicides for managing root?knot nematodes.
- The demonstration that rotation crops can control lesion nematodes and potato early dying disease may lead to effective non-chemical management, increasing yield and reducing pesticide use. The identification of strawberry cultivars resistant or tolerant to black root rot would greatly assist disease management.
- Validation of alternative nematode management tactics and demonstration of their economic benefits will provide growers with additional tools for reducing pesticide use, lowering control costs and crop losses, and providing a more sustainable strategy for managing nematodes in vegetable and field crop rotation.
- The immunoassay using a monoclonal antibody against an adhesin epitope on the surface of the endospores of P. penetrans provides a quantitative measure of the densities of endospores in soil and in infected nematodes. The assay should be useful to other scientists assessing the extent to which soils are or may become suppressive for nematode infestations and thereby limit the need for other control measures.
- The development of oligonucleotides complementary to DNA sequences of the sporulation genes of P. penetrans has provided probes and primers for quantifying P. penetrans infections in planta. A rapid method using real-time PCR has been developed. This provided an approach that is complementary to the immunoassay, allowing detection and quantification of P. penetrans at all stages of development.
Date of Annual Report: 12/09/2004
Report Information:
Participants:
- Magnarelli, Louis (Louis.Magnarelli@po.state.ct.us) - Connecticut Agric. Exp. Station
- Abawi, George (Gsa1@nysaes.cornell.edu) - Cornell University, Geneva, NY
- Bernard, Ernest - University of Tennessee
- Bird, George (birdg@msu.edu) - Michigan State University
- Desaeger, Johan - University of Georgia
- Dickson, Don (Dwd@ufl.edu) - University of Florida
- Green, James , CSREES Advisor - USDA-CSREES, Washington, DC
- Halbrendt, John (Jmh23@psu.edu) - Penn State University, Fruit Res & Ed Ctr
- Huettel, Robin - Auburn University
- Kotcon, Jim (Jkotcon@wvu.edu) - West Virginia University
- LaMondia, Jim, Chair (James.LaMondia@po.state.ct.us) - Connecticut Agric. Exp. Station
- Meyer, Susan (Smeyer@asrr.arsusda.gov) - USDA-ARS, Beltsville, MD
- Preston, James (Jpreston@ufl.edu) - University of Florida
- Thies, Judy (Jthies@saa.ars.usda.gov) - USDA-ARS, Charleston, SC
- Zasada, Inga , Secretary - USDA-ARS, Beltsville, MD
Brief Summary of Minutes of Annual Meeting:
URL: Copy of minutes
Accomplishments:
2000: " Establish a low soil volume bioassay to evaluate nematode antagonistic crops.A low volume soil bioassay developed in PA was used to evaluate toxicity of green or freeze-dried plant extracts on plant parasitic nematodes in CT, MA, NY, and WV.
" Conduct a workshop for all group members to present protocols for Pasteuria penetrans recognition, research and surveys.
A workshop conducted in FL to taught members to recognize Pasteuria spp. on different species of nematodes with the goal that all members follow prescribed methods in working with Pasteuria.
" Initiate collaborative rotation and cover crop system research in field plots and microplots in multiple states.
Collaborative multi-state interdisciplinary competitive projects were awarded to NE171 scientists. Maryland participated in a grower-generated project on the use of cover crops, soil amendment, and tillage to manage root knot. A multidisciplinary project was funded to Michigan, Wisconsin, New Jersey and New York. Grower trials were conducted on rotation and cover crops, resistance, biological control, and natural products. The host status of nematode-suppressive rotation crops or green manures was investigated on nematodes in CT and PA.
" Identify and evaluate nematode resistant or tolerant varieties for inclusion in an integrated management program.
A number of crops were evaluated for resistance or tolerance to nematodes, including the USDA Capsicum germplasm collection for reaction to Meloidogyne (USDA-SC); strawberry cvs were evaluated against black root rot pathogens in CT; Onion germplasm (>50 accessions of Allium spp.) were evaluated against M. hapla (NY); carrot cvs were evaluated against M. hapla (NY); and selected soybean cvs were found to be hosts to P. penetrans. Bell pepper (Capsicum annuum) cvs near isogenic for the N gene for resistance to root knot were evaluated (USDA-ARS-SC); and C. colocynthis (21) and C. lanatus var. citroides (88) accessions, and C. lanatus var. lanatus (155) accessions from the U.S. Citrullus collection were evaluated against M. arenaria race I. Results demonstrated resistance, tolerance, or genetic variability within the cultivars or PI's tested.
2001: " Survey northern states for the presence of Pasteuria penetrans using protocols identified in 2000.
Pasteuria penetrans or Pasteuria-like organisms were discovered attached to Heterodera iri from turf (CT). Pasteuria were detected in 77% of Long-Term Ecological Research plots in MI. Pasteuria spp. were associated with plant nematodes, fungivores and bacterivores. A New York survey detected Pasteuria from Tylenchorhynchus spp., Tylenchus spp., and Meloidogyne sp. Free-living Cephalobus sp. and Eucephalobus sp. were also found with endospores. Samples from putting greens in MA all had Pasteuria-infected Tylenchorhynchus. Other nematodes with Pasteuria included Helicotylenchus, Hoplolaimus and Meloidogyne. Conditions were defined for detection of Pasteuria spp endospores using a monoclonal antibody against an epitope of the parasporal fibers that cover mature endospores. An amplification ELISA using biotinylated secondary antibody quantified a minimum of 300 endospores per g soil, and may also quantify endospores in roots. FL developed DNA probes for detection of vegetative stages of Pasteuria using published genome sequences for Bacillus subtilis and B. halodurans, free-living endospore-forming bacteria, as a basis for designing primers for PCR amplification of orthologous genes from Pasteuria. Degenerate primers and anealing conditions were used to amplify PCR products using DNA templates obtained from P. penetrans P20 endospores. Using Real-Time PCR, M. arenaria infection level by vegetative cells of P. penetrans was determined. The assay selectivity was confirmed as primers did not detect DNA in uninfected M. arenaria. This work identified gene sequences unique to P. penetrans. Using these primers, the level of infection by P. penetrans may be determined before sporulation. This will be complementary to the immunoassay recognizing an epitope present on mature spores.
" Evaluate crops and greenhouse or growth chamber systems for the production of large numbers of Pasteuria penetrans endospores.
Rutgers tomato and PA136 Bell pepper were selected as hosts for culture of Meloidogyne incognita based on root vigor and cultural manageability, and grown in a greenhouse soil moisture control system (Sardanelli and Kenworthy, 1997).
Root-knot density and Nemacur treatment were evaluated in MA for impact on the incidence of infection by Pasteuria. There was an inverse relationship between nematode numbers and Pasteuria. Nematicide did not affect the incidence of Pasteuria infection.
2002: " Initiate research to determine the mechanism of nematode antagonism in rotation and cover crops.
A bioassay developed in PA using freeze-dried plant material was used to detect the presence of potential nematicidal compounds. Xiphinema americanum were exposed to freeze-dried leaf and root tissue. Nematodes were not killed in sterile sand or water, and mortality increased with amounts of tissue. The LC50 ranged from 0.6 mg (Nasturtium) to 13.2 mg (Sunn hemp) per cc of sand. Nasturtium leaves showed potent nematicidal activity with an LC50 of 0.6 mg.
(CT) In cooperation with PA, the host status of several rotation crops was evaluated against Pratylenchus penetrans and Meloidogyne hapla. Shoot incorporation indicated that plant breakdown products may be nematicidal.
" Compare isolates of Pasteuria penetrans for host preference and biocontrol potential.
The long-term persistence and suppression of Pasteuria penetrans against Meloidogyne arenaria were investigated over 9 years of crop cultivation and weed fallow in FL. FL developed a monoclonal to quantify Pasteuria endospores in soil. We also developed assays for DNA sequences unique to different species of Pasteuria to quantify host specificities. The incidence of the bacterium was related to the density of the peanut root knot nematode, but not M. javanica.
(MA) The relationship of Pasteuria penetrans to Meloidogyne graminis and Tylenchorhynchus spp was investigated on golf greens. A correlation between percent Pasteuria- encumbered juveniles and the density of M. graminis and Tylenchorhynchus was found.
" Evaluate the impact of rotation and cover crops and soil amendments on nematodes.
Experiments were conducted combining an alkaline-stabilized biosolid (ASB) amendment with Streptomyces sp. for M. incognita control. Only ASB at the highest rate (3% wt/g soil) reduced M. incognita. No suppression was achieved by applying Streptomyces sp. to soil (USDA ARS Beltsville).
(PA) Compost was evaluated for ability to suppress dagger nematodes in an apple orchard. Plots treated with five inches of mushroom compost consistently had the lowest nematodes, suggesting that mushroom compost is suppressive to dagger nematodes.
(CT) Rotation and green manure crops resulted in lower lesion nematode densities. Incorporation of crop shoots further reduced nematodes. Rudbeckia and marigold controlled nematodes without incorporation. A single season of marigold controlled P. penetrans and increased tuber yields in potato plots.
The effects of the organic butyric and propionic acids against Meloidogyne hapla on tomatoes and Pratylenchus penetrans on strawberries in RI indicated that Vydate and butyric acid treatments were similar.
2003: " Evaluate the winter survival of Pasteuria penetrans in northern states.
(MA) Pasteuria penetrans on Meloidogyne graminis and Tylenchorhynchus has overwintered on turf in golf greens in Massachusetts. Pasteuria spores were present on the cuticles of M. hapla juveniles after exposure to winter conditions in CT. Pasteuria endospores appear to readily survive the winter in CT, MA, NY and MI.
" Determine the sequence of events required for formation of endospore-associated proteins and adhesion to nematodes.
(FL) Pasteuria penetrans cannot be grown in vitro or enumerated by bacteriological methods; therefore, an immunoassay was developed to quantify spores. A monoclonal antibody (MAb) produced against whole spores was shown to bind a putative glycan epitope present on the spore envelope. Following SDS-PAGE of cuticle extracts and immunoblotting with spore extracts and the MAb as probes, the glycopeptides were shown to bind to discrete polypeptides derived from the nematode cuticle. The MAb detects an epitope of adhesins that are involved in the attachment of Pasteuria endospores to the nematode cuticle. An indirect amplification ELISA was developed to quantify spore adhesins. Regression of spore concentration versus signal produced line fits of 0.98 and indicated a detection limit of 3000 spores/g 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 adhesins in soil. The MAb did not detect antigens on cells or endospores derived from other endospore-forming bacteria. This establishes the MAb as a definitive probe to detect adhesins as virulence determinants on Pasteuria endospores in soil.
" Integrate plant resistance with rotation crops to predict nematode population decline under integrated management systems.
Potato cvs were rated for root-galling severity in NY. All potatoes tested had galls on fine fibrous, but not coarse roots. Large numbers of eggs were recovered from all cvs, which were hosts of M. hapla. Carrot cvs were evaluated against M. hapla. All cultivars tested were hosts of M. hapla.
Black root rot is a strawberry disease caused by Rhizoctonia fragariae and Pratylenchus penetrans. Cultivars that performed well in yield and vigor after 3 years in infested soils in CT were Latestar, Primetime, Annapolis, Lester, Idea, Winona and Earliglow.
Results from USDA-ARS SC demonstrated genetic variability within the U.S. PI Citrullus germplasm collection for resistance to M. arenaria race 1. The C. lanatus var. citroides accessions are sources of resistance to M. arenaria race 1 in watermelon. Peppers with the N gene for resistance to southern root-knot nematode have been useful in management. A pepper PI with moderate resistance to M. hapla has been identified for use in the Northeast.
2004: " Evaluate rotation and cover crop effects on nematode community structure in soil.
A workshop on identification of free-living nematodes at the 2002 Technical Committee Meeting was held to assist researchers evaluating the impact of nematode management on nematode community structure. Dr. Bird has prepared chapters on 'nematode biology and management' & 'nematodes and soil quality' in two interdisciplinary MSUE Bulletins. The effects of seasonal changes in nematode community structure were determined in long-term ecological plots in MI.
" Determine the morphological and phylogenetic relations among Pasteuria penetrans isolates.
Phylogenetic analysis of the sigE gene from gram-positive endospore-forming bacteria finds Pasteuria penetrans most closely related to Paenbacillus polymyxa. SigE is a sporulation gene with sequence diversity for species and biotype differentiation of Pasteuria. The development of a DNA library from Pasteuria represents a special case. The GenomiPhi process was evaluated from Bacillus subtilus cells and indicates that a complete Pasteuria library may be prepared from as little as 1000 bacterial genomes from single nematodes.
" Develop an economic analysis of rotation and soil amendment tactics for nematode control.
The analysis of nematode community structure in long-term ecological sites in MI has led to 5 proposed categories of soil health and quality based on disturbance, soil nutrient/amendment inputs, and system degradation. Within a category, rotation with nematode-resistant soybeans has shown an economic advantage of 9 to 26%.
Impact Statements:
- (CT) The effect of initial Pratylenchus penetrans densities in soils infested with a history of black root rot were incorporated into a strawberry economics model developed by Alison DeMarree & Regina Rieckenberg at Cornell University. Initial lesion nematode densities as low as 12 per g root resulted in an 11% loss over 4 years and densities as high as 125 per g root resulted in 100% loss in profit over the same time.
- (CT) Studies on the interaction of the fungal and nematode pathogens in strawberry black root rot will help to maximize sampling to determine if nematodes are involved in black root rot, the contribution of the nematode to disease, and may help to manage the disease complex.
- (CT) The identification and use of rotation crops that reduce both strawberry black root rot pathogen populations in soil will reduce the use of soil fumigants. The identification of strawberry cultivars resistant or tolerant to black root rot would further reduce pesticide use and economic losses to disease.
- (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. Precision agriculture techniques had the potential to increase net profit at the study site by $304 per acre.
- (MA) The demonstration that natural enemies for biological control, such as Pasteuria, may be destroyed by fumigation may encourage growers to use fewer broad spectrum pesticides and adopt biological or cultural controls.
- (NY, Geneva) Assessing the genetic and pathological characteristics of nematode populations, such as Meloidogyne hapla, is critical for identifying resistant crop germplasm, designing effective crop rotations, and developing diagnostic tools.
- (NY, Geneva) The development of a simple bioassay to predict damaging nematode population levels by growers has reduced crop losses, environmental exposure to pesticides and human health risks.
- (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.
- (USDA, SC) The northern root-knot nematode causes serious damage to pepper in the U.S. and worldwide. The development of cultivars with genetic resistance to root knot is the most efficient and environmentally benign way of controlling this problem without to the use of soil fumigation. As there are no pepper cultivars with resistance to M. hapla, the identification of a PI with moderate resistance to M. hapla is a significant and important finding.
- (FL) The monoclonal antibody 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 by researchers for evaluating chemical and biological measures required for control of root-knot nematodes.
- (FL) The immunoassay using a monoclonal antibody against an adhesin epitope on the surface of the endospores of P. penetrans provides a quantitative measure of the densities of endospores in soil and in infected nematodes. The assay should be useful in assessing the extent to which soils are or may become suppressive for nematode infestations and thereby limit the need for other control measures.
- (FL) The development of oligonucleotides complementary to DNA sequences of the sporulation genes of P. penetrans has provided probes and primers for quantifying P. penetrans infections in planta. A rapid method using real-time PCR has been developed. This provided an approach that is complementary to the immunoassay, allowing detection and quantification of P. penetrans at all stages of development.
- (FL) The determination of the sequences of genes from other species/strains of Pasteuria should allow the development of probes with which to distinguish and identify host specific strains in different ecological settings.
- (MD) The refinement of nematode sampling recommendations, validation of alternative nematode management tactics and demonstration of their economic benefits provide growers with additional tools for reducing pesticide use, lowering control costs and crop losses, and providing a more sustainable strategy for managing nematodes in vegetable and field crops.
- (MI) Data on the influence of management systems on nematode community structure confirm that impacts on soil biology can be detected and predicted through the use of nematode community structure analysis.
- (USDA-ARS, FLA) Cooperative research on PGPR formulations with Gustafson LLC has resulted in a new commercial product for use on transplanted crops, BioYieldTM, consisting of a formulation of plant growth and yield enhancing bacteria. This product will be a low toxicity alternative to pesticides, reducing environmental and human exposure.
- (USDA-ARS, SC) None of the bell pepper cultivars currently available have sufficient resistance to Meloidogyne incognita. Results of controlled environment studies indicate that root-knot resistant cultivars such as Charleston Belle that are homozygous (NN) for the N gene value as parental lines for developing resistant F1 hybrid (Nn) bell pepper cultivars. These hybrids should exhibit the same level of resistance as the Charleston Belle parent.