BIOLOGY, HOST RANGES, AND DAMAGE LEVELS
OF ROOT-PARASITIC NEMATODES ON PACIFIC NORTHWEST GRASSES
Kathy Merrifield
Oregon State University Nematode Testing Lab
1089 Cordley Hall, Corvallis OR 97331-2903
March 1999: Version 2
Contents of this Survey:
Damage Levels: An Introduction
Host designations based on gall ratings
Host designations based on Reproductive factor (Rf)
Host designations based on number of plants infected
compared to number of plants inoculated
Biology of Nematode Genera:
Criconemella
Heterodera
Longidorus and Xiphinema
Meloidogyne
Paratylenchus
Pratylenchus
Trichodorus and Paratrichodorus
Tylenchorhynchus
Host Ranges and Damage Levels Listed Alphabetically
by Grass Genus and Species
Aegilops
Agropyron
Agrostis
Alopecurus
Arrhenatherum
Avena
Beckmannia
Bouteloua
Brachypodium
Bromus
Cenchrus
Cynodon
Dactylis
Digitaria
Echinochloa
Eleusine
Elytrigia
Elymus
Elytrigia
Eragrostis
Eremochloa
Festuca
Hordeum
Koeleria
Lolium
Panicum
Pascopyrum
Pennisteum
Phalaris
Phleum
Poa
Polypogon
Pseudoroegneria
Secale
Setaria
Sorghum
Spartina
Thinopyrum
Triticum
Vulpia
Zea
Literature Cited
DAMAGE LEVELS: AN INTRODUCTION
How many plant-parasitic nematodes will damage a particular plant
species? This is the most frequently asked question of the
Nematode Testing Service at Oregon State University. This
literature survey is an attempt to answer that question for grass
species including cereals that grow in the Pacific Northwest.
Non-quantitative host range information is also included to
facilitate control through crop rotation: if remaining weeds
are host to a plant-parasitic nematode, the nematode population
can be maintained in the weeds even if the crop itself is not a
host.
Most information listed below is from replicated studies or
systematic surveys. Studies conducted in pots or microplots are
indicated. Study conditions may deviate from local Oregon
conditions in soil type, climate, moisture, and other factors.
Cultivars often vary in susceptibility to parasitic nematode
damage and in the number of nematodes they will support.
Numbers of most plant-parasitic nematodes vary seasonally. In
many of these studies, the season at which samples were taken is
not indicated. In some, however, nematode numbers are designated
as initial or as final levels.
These studies report levels at which damage has occurred rather
than predict damage that will occur. Therefore, these data are
presented only to give suggestions of nematode levels at which
damage may occur.
If a particular crop is not included in the list, no information
has been found for that crop. If a nematode species of concern is
not listed under a particular crop, no information has been found
on the species for that crop. A lack of information does not
necessarily imply a lack of damage.
Nematode damage numbers in this survey are expressed in this
survey as nematodes/100 grams (g) soil or number of nematodes/100
cubic centimeters (cm3 or cc) soil. Numbers/100 g soil may be
multiplied by 20 to give the number of nematodes/2000 g soil
(traditionally designated by the OSU Nematode Testing Lab as one
"quart"). Nematode numbers from the OSU Nematology Lab are
reported as number/100 g and are corrected for soil moisture.
Nematode numbers/100 cm3 soil can provide a rough estimate of
numbers/100 g soil corrected for dry weight but should be divided
by the soil bulk density for accuracy. Bulk densities of clay,
clay loam, and silt loam surface soils range from about 1.0 to
1.6 g/cm3, and those of sands and sandy loams range from about
1.2 to 1.8 g/cm3 (Buckman and Brady 1969). However, the bulk
density of the sample actually processed is dependent upon
packing density during measurement. Since bulk densities are
not frequently reported in studies in which nematode numbers are
expressed on a volume basis, accurate conversion of numbers/100
cm3 to numbers/100 grams soil is not usually possible.
Nevertheless, since the variation associated with bulk density
conversions is generally less than the variation associated with
field sampling, numbers/100 cm3 soil provide an acceptable
approximation of numbers/100 g soil for making management
decisions.
HOST DESIGNATIONS BASED ON GALL RATINGS: These designations
apply only to Meloidogyne. A rating of "1" = no galls
(resistant); "2" = 1 to 10 galls; "3" = 11 to 100 galls;
"4" = more than 100 galls (susceptibile) (LaMondia 1995, LaMondia
1996).
HOST DESIGNATIONS BASED ON REPRODUCTIVE FACTOR (Rf). Rf = final
population/initial population. An Rf of over 10 indicates an
excellent host; an Rf of 1 to 10 indicates a good host; an Rf of
about 1 indicates a maintenance host; and an Rf of between 1 and
0 indicates a poor host or nonhost (Ferris et al. 1993).
HOST DESIGNATIONS BASED ON NUMBER OF PLANTS INFECTED COMPARED TO
NUMBER OF PLANTS INOCULATED. This is expressed as a fraction.
If 10 plants were inoculated and 5 were infected, then 5/10
inoculated plants were infected (Faulkner and McElroy 1964).
BIOLOGY OF NEMATODE GENERA
CRICONEMELLA
Criconemella, the ring nematodes, are migratory
root ectoparasites. Plump, stubby bodies, coarsely and strongly
annulated ("ringed") cuticles, and long, heavy stylets render
them distinctive even under the dissecting microscope. Adults of
C. xenoplax are about 0.4 mm long.
The life cycle of Criconemella is typical of all migratory root
ectoparasites considered in this survey. They spend their entire
lives in the soil outside the root, puncturing cells and sucking
out cell liquids. Females lay eggs in the soil. The first of
four molts occurs inside the egg, and the nematodes hatch as
second stage juveniles (J2). The juveniles enlarge during the
next two molts. Sex organs do not appear until after the fourth
and final molt to adulthood. Males are necessary for reproduction
in some species but not in others. Females lay eggs, and the
cycle begins again.
Criconemella spp. are often found in various mosses including
Sphagnum and also in riverside and lakeside mud (Goodey 1951).
They are often found in turf, sometimes in large numbers (Christie
1959). Criconemella curvatum and an unidentified Criconemella
species have been recovered from turf in coastal and central
Oregon in 1997 and 1998. Much more information on C. xenoplax
exists than on most other species in the genus, and it is the only
species addressed in this survey.
HETERODERA
This genus comprises the cyst nematodes, sedentary
endoparasites named for the fat, exposed mature female. J2 and
adult females are about 0.5 mm long, and males reach about 1.0 mm.
Second stage juveniles hatch from eggs and enter new host roots
near the tips, destroying cells in their paths. They establish a
permanent feeding site of several cells with partially dissolved
walls. Both males and females fatten at first, but during
subsequent molts, the male becomes thin and motile; it leaves the
root as an adult and mates with a female. The female continues to
fatten in this, her permanent home, achieving nearly spherical
plumpness by adulthood following the fourth molt. Cortical cells
are destroyed, and the root cracks to accomodate the flourishing
female, exposing all but her anterior end, which is still feeding.
Eggs may remain alive packed inside the female for several years,
protected by her cuticle, which becomes a leathery "cyst" after
her death. J2 become active in response to root exudates. Life
cycles take about 3 to 4 weeks. Most cyst nematode species have
narrow host ranges.
Heterodera avenae has been known in Ontario, Canada for decades
(Norton et al. 1984). It was reported in Oregon in 1975 (Jensen
et al. 1975). Its primary host crop is oats, but other cereals
and other grasses are also parasitized. Many grasses are hosts,
and even those that are not good hosts can maintain populations
between cereal crops (Williams and Siddiqi 1972). Higher numbers
and more severe damage have been reported in lighter soils. It
completes only one generation per year (Norton et al. 1984).
Hatch in increased by cereal root exudates and occurs best at 10
C, although temperature relationships are complex (Norton et al.
1984).
Heterodera goettingiana, Heterodera humuli, Heterodera schachtii,
and Heterodera trifolii are also present in Oregon, but they do
not usually parasitize grasses. Heterodera trifolii may be the
most widespread cyst nematode in North America (Norton et al.
1984), and it may be detected in grass or grain soil samples due
to its parasitization of legumes which may be weeds.
Recovery of Heterodera is unusual in OSU Nematode Testing Service
samples.
LONGIDORUS AND XIPHINEMA
The life histories of these two migratory ectoparasic genera,
the needle and dagger nematodes, respectively,
resemble that of Criconemella, but their anatomy is
different. Their long stylets enable them to feed on deep
tissues, and they may even penetrate the stele. This feeding
causes necrosis, shrivelling, and stunting of young roots and
reduction of above-ground growth as well as root galls in some
cases. Both genera can vector viruses, but grasses do not appear
to be hosts of the viruses vectored.
Members of both genera are larger than other plant parasites,
sometimes exceeding 5 mm. They are barely visible to the unaided
eye when floating in clear water, but they are not visible when
in soil.
Xiphinema species included in this survey are limited to those
detected on Pacific Northwest grasses: X. americanum, X. bakeri,
and X. index (reported for Oregon (Norton et al. 1984) but rare).
Longidorus elongatus is the only species known to parasitize
grasses in Oregon. Longidorus sylphus and L. menthosolanus are
synonyms of L. elongatus.
MELOIDOGYNE
The sedentary endoparasitic root-knot nematodes
(Meloidogyne spp.) hatch from eggs and enter roots as second
stage juveniles (J2), select a feeding site of three to eight
cells, and swell in their chosen site as they progress through
two more juvenile stages towards adulthood. They introduce
hormone-like substances into the plant cells, causing the
formation of a rich feeding site containing multiple nuclei and
excess proteins. The resulting swellings are called galls or
knots. Males regain their slender profiles and leave the root
at adulthood, but the fattened adult females remain inside,
exuding eggs into the soil within a gelatinous matrix. First
stage juvenile nematodes (J1) develop within the eggs, undergo
their first molt to J2, hatch, and migrate through soil before
entering host plant roots. Adult females are about 0.7 mm long,
J2 are about 0.4 mm long, and males are 1-2 mm long.
Roots inhabited by root-knot nematodes often have visible galls
and may exhibit excessive branching. Parasitized plants may be
weak and stunted, and root systems may be deformed. However,
galling is not essential for nematode feeding, and gall
development may be inconspicuous or absent on some hosts
(Kleynhans et al. 1996).
Meloidogyne species included in this survey are those detected on
or associated with Oregon agricultural crops, weeds, and native
plants. These are M. hapla, M. chitwoodi, and M. naasi.
Meloidogyne chitwoodi reproduces better during cool growing
seasons than does M. hapla, but both species have a higher
tolerance for cooler soil temperatures than most other common
North American Meloidogyne species (Nyczepir et al. 1982, Norton
et al. 1984). The optimum temperatures for M. hapla life cycle
completion are 25 to 30o C (Norton et al. 1984). Meloidogyne
naasi survived well at 16o C and reproduced between 16 and 32o C,
but reproduction was best at 27o C (Norton et al. 1984).
Small grains and cereals are good hosts for M. chitwoodi, but
most are non-hosts for M. hapla (Nyczepir et al. 1982), as are
other grasses. Meloidogyne naasi is a parasite primarily of
Poaceae and Chenopodiaceae, often doing greater damage in wet and
compacted soils.
PARATYLENCHUS
The life cycle of the migratory ectoparasitic
pin nematodes resembles that of Criconemella. Adults are about
0.4 mm long. Paratylenchus in our area cannot be identified to
species because they belong to one or more undescribed species.
Thus, damage levels by nematode species cannot be listed.
Paratylenchus is not considered damaging on most crops except
in high numbers, usually 500/100 g soil or more. They have been
recovered from grass samples by the OSU Nematode Testing Service.
PRATYLENCHUS
The migratory endoparasitic root-lesion nematodes
(Pratylenchus spp.) create holes in root cells and crawl inside.
They move longitudinally through the cortex, piercing, sucking,
and leaving behind a trail of eggs and toxic metabolites. Eggs
deposited in both roots and soil hatch, and the life cycle
continues through four molts to sexual maturity and reproduction.
Root cell death results in brown longitudinal root lesions, which
begin on one side but may eventually encircle a root and thereby
girdle it. The overall effect is a weak, shallow root system
with extensive dead areas. Pratylenchus spp. are disseminated by
transportation of soil or plant parts and by surface or irrigation
water (Evans et al. 1993). Adults are about 0.5 mm long.
Pratylenchus species included in this survey are limited to those
detected on Oregon agricultural crops: P. crenatus, P. neglectus,
P. penetrans, and P. thornei.
Pratylenchus crenatus, formerly known as P. pratensis, reproduces
best at 10-15o C in sand or silt loam (Norton et al. 1984). Its
wide host range includes many grasses.
Pratylenchus neglectus is synonymous with P. minyus (Norton et
al. 1984). It has a very wide host range. Populations after 70
days were highest on peppermint at 24o C when both the nematode
and Verticillium dahliae were present (Faulkner and Bolander
1969). It penetrated host roots better in sandy loam than in
silt loam soils (Brown et al. 1980).
Pratylenchus penetrans also has a very wide host range. Its
density does not appear to be affected by soil texture (Norton et
al. 1984). Reproduction in peppermint was much greater at 30o C
than at 22.5o C and 15o C (Patterson and Bergeson 1967). However,
population increase was greatest on potatoes at 16 C and on corn
at 24o C (Acosta and Malek 1979).
Pratylenchus thornei has been recovered from a variety of plant
species but is most commonly associated with grasses. It can
cause marked damage on wheat and barley.
TRICHODORUS AND PARATRICHODORUS
These two genera, the stubby-root
nematodes, are distinguished only by characteristics visible under
high compound microscope magnification. Adults are about 0.7 mm
long. They have slender, curved stylets and stout, blunt-ended
bodies. Species included in this survey are limited to those
detected on Oregon agricultural crops or those in nearby states
and provinces: P. allius, P. minor (formerly T. christei), P.
teres, Trichodorus aequalis, and T. obscurus. Only P. allius has
been positively identified by the OSU Plant Clinic Nematode
Testing Lab.
The life cycle of this migratory ectoparasite resembles that of
Criconemella. The nematodes feed mostly at root tips but also
along the sides of young, succulent roots. Root tip growth is
slowed or stopped, resulting in a generally stunted root system
or in short, stubby roots. Like Xiphinema and Longidorus, stubby-
root nematodes can vector plant viruses, but none appear to be
problems on grasses.
According to Norton et al. (1984), Paratrichodorus allius
reproduced between 21 and 26o C. Lighter textured soils supported
the highest numbers. The life cycle of P. minor is completed in
21-22 days at 22 C and in 16 - 17 days at 30 C; the optimum
temperature for reproduction is 25 C. Optimum soil moisture for
reproduction is near 10%. In cranberry bogs, populations peaked
in November and December. In Georgia, they peaked in June.
Tylenchorhynchus and similar genera. These are migratory root
ectoparasites whose life cycle resembles that of Criconemella.
Because their feeding can result in a stunted root system, they
are called "stunt nematodes." Adults are about 0.6 to 0.8 mm
long. Tylenchorhunchus and related genera are commonly recovered
from Pacific Northwest soils. Because they appear to do little
damage, however, little attention is paid to them, and the genera
involved remain in question. Tylenchorhynchus claytoni occurs in
Oregon (Norton et al. 1984).
HOST RANGES AND DAMAGE LEVELS LISTED BY GRASS GENUS AND SPECIES
AEGILIPS CYLINDRICA (jointed goatgrass)
Meloidogyne chitwoodi
In pots, trace reproduction: very poor host (O'Bannon et
al. 1984).
AGROPYRON COMPLEX (wheatgrasses): A. cristatum, A cristatum X
desertorum, A desertorus, A. riparium, A. trachycaulum, A.
trichophorum, Elymus lanceolatus, Elytrigia repens, Pascopyrum
smithii, and Thinopyrum intermedium
Heterodera avenae
Host; can maintain populations between cereal crops (Williams and
Siddiqi 1972)
Meloidogyne chitwoodi
Nordan, Fairway, and Highcrest were suppressed about 24 to
40% at 185 eggs/100 cc and about 29 to 56 % at 926 eggs/100 cc
inoculations of Utah, Idaho, California, and Washington
populations at planting (Griffin and Asay 1989).
Mean Rf: 16.5 (Jensen and Griffin 1994).
Nordan is a good host (Rf = 2.8) (Griffin et al. 1984).
Meloidogyne hapla
In pots, Agropyron cristatum, A. desertorum, A. riparium, and A.
trichophorum were not susceptible, and no inoculated plants were
infected (Faulkner and McElroy 1964).
Pratylenchus neglectus
Initial density of 400/100 cm3 soil reduced cv. Hycrest Crested,
Fairway Crested, Nordan Crested, Greenar Intermediate, and Secar
Snake River shoot weights by 22 to 49% and root weights by 26 to
42% (Griffin 1992b).
Greatest yield reduction was at 800/100 cm3 soil, but
damage observed at 200/100 cm3 (Griffin & Jensen 1997).
Pratylenchus penetrans
A. cristatum, A. intermedium, and A. trachycaulum Primar
were experimentally infected with P. penetrans (Jensen 1953).
Xiphinema americanum
Fairway crested (Agropyron cristatum), Hycrest crested (A.
cristatum X A desertorum), "Rosana" western (Pascopyrum smithii),
"Oahe" intermediate (Thinopyrum intermedium), and RS-1 hybrid
(Elytrigia repens X Pseudoroegneria spicata) are hosts (Griffin
et al. 1996).
Agropyron mongolicum (Mongolian wheatgrass)
Meloidogyne chitwoodi
Mean Rf: 4.5 (Jensen and Griffin 1994).
AGROPYRON REPENS (quackgrass)
Meloidogyne chitwoodi
In pots, trace reproduction: very poor host (O'Bannon et al.
1984).
Meloidogyne naasi
Host for 4 US and 1 English population (Michell et al. 1973a).
AGROSTIS CANINA (Astoria bentgrass)
Meloidogyne naasi
Host for 4 US and 1 English population (Michell et al. 1973a).
Xiphinema americanum
In pots, 169 days after inoculation with 72/100 g soil, the
final population was 8/100 g soil (Miller 1980).
AGROSTIS PALUSTRIS (= A. alba; creeping bentgrass, redtop)
Meloidogyne hapla
In pots, redtop as not susceptible, and none of 23
inoculated plants were infected (Faulkner and McElroy 1964).
Penncress and Seaside are hosts (Radewald et al. 1966, Radewald
et al. 1970).
Meloidogyne naasi
67/100 cm3 soil in pots alone and with 67/100 ml of both
Pratylenchus penetrans and Tylenchorhynchus agri significantly
reduced top growth and in root weight after 10 but not 6 months
(Sikora et al. 1972).
24/100 cm3 soil in pots resulted in densities of 84 to
1763/g root after 8 months; all but one of 5 races caused
significant reduction in top weights but usually not root
weights (Michell et al. 1973b).
Causes severe damage (Franklin 1973).
Toronto C-15 is a host for 3 US but not California and
English populations (Michell et al. 1973a).
Host for 4 US and 1 English population of redtop (Michell
et al. 1973a).
Pratylenchus penetrans
In pots, inhibited top growth only when co-inoculated with
Meloidogyne naasi. A.s palustris is a poor host for Pratylenchus
penetrans (Sikora et al. 1972).
AGROSTIS TENUIS (colonial bentgrass)
Meloidogyne naasi
Highland is a host (Radewald et al. 1970).
AGROSTIS SP. (Bentgrass, unspecified)
Heterodera avenae
Host; can maintain populations between cereal crops
(Williams and Siddiqi 1972).
Longidorus elongatus
Associated (Norton et al. 1984).
Pratylenchus thornei
Host in Mexico (Fortuner 1977).
ALOPECURIS PRATENSIS (meadow foxtail)
Meloidogyne chitwoodi
In pots, no reproduction: non-host (O'Bannon et al. 1984).
Pratylenchus penetrans
Tualatin was experimentally infected with P. penetrans
(Jensen 1953).
ALOPECURIS SPP. (Foxtail)
Heterodera avenae
Host; can maintain populations between cereal crops
(Williams and Siddiqi 1972)
ARRHENATHERUM ELATIUS(onion twitch, tall oatgrass)
Meloidogyne chitwoodi
In pots, no reproduction: non-host (O'Bannon et al. 1984).
Meloidogyne naasi
Host (Franklin 1965).
Pratylenchus penetrans
Experimentally infected with P. penetrans (Jensen 1953).
AVENA FATUA (wild oats)
Heterodera avenae
Host; can maintain populations between cereal crops
(Williams and Siddiqi 1972).
Host in New Zealand (Knight et al. 1997).
Heterodera schachtii
Host (Bendixen et al. 1979)
AVENA NUDA
Xiphinema americanum
In pots, 169 days after inoculation with 72/100 g soil, the
final population was 0/100 g soil (Miller 1980).
AVENA SATIVA (oats)
Heterodera avenae
Causes stunting and chlorosis, branched root systems, and
patchy growth, grain formation is inhibited (Kleynhans et al.
1996).
Its main effect is suppression of root elongation (McGawley
and Overstreet 1998).
Host (Williams and Siddiqi 1972).
Severely affected (Christie 1959).
Heterodera schachtii
Host (Bendixen et al. 1979)
Meloidogyne chitwoodi
In pots, Ottawa and Cayuse were good hosts (Rf = 6.5 and
4.2) for race 1 (Ferris et al. 1993).
In pots, Park was a is a suitable host (Rf = 24.5) for
Race 2 (alfalfa race) (Mojtahedi et al. 1988b).
In pots, cv. Appaloosa, Cayuse, Corbit, Markton, Menominee,
Otana, Random, and Terra suppored high reproduction: very good
hosts. Park supported high reproduction: good host (O'Bannon
et al. 1984).
At 500 eggs/liter soil, Park roots but not top growth
weighed less than uninoculated controls; at 5000 eggs/liter,
total plant dry weight was less than uninoculated controls M.
chitwoodi increased from 8 to 11 times on Park oats (Santo and
O'Bannon 1981).
In pots, Rf of 2.3 on Park from inoculation of approximately
200/100 cm3 soil (Santo et al. 1980).
Meloidogyne hapla
In pots, not susceptible, and 0/16 inoculated plants were
infected (Faulkner and McElroy 1964).
In pots, "Lee" was a host (Gaskin and Crittenden 1956).
In pots, Rf of 0 on Park from inoculation of approximately
200/100 cm3 soil (Santo et al. 1980).
Meloidogyne naasi
Wintok is a host for four US and one English population
(Michell et al. 1973a).
Sierra is a host (Radewald et al. 1970).
Red rustproof, Chinese Hull-less, Swedish select, Algerian,
Pusa Hybrid J. Canuck, Sure Grain, Avoine-crena, and Punjab
Algerian are resistant; some of these varieties are from Asia
and South America (Siddiqui and Taylor 1970).
Diane acts as a trap crop: it is heavily invaded by J2, none of
which was found to develop beyond the second stage (Franklin 1973).
Pratylenchus spp.
Moderately damaged (Kleynhans et al. 1996).
Pratylenchus crenatus
Damage occurs at 33/100 cm3 soil (Barker et al. 1976).
Pratylenchus penetrans
In pots, initial populations of 33/100 g soil resulted in
150/g root and little necrosis after 3 months (Miller 1978).
In pots, 796% increase of initial inoculum on Vicar
(McDonald and Mai 1963).
Pratylenchus thornei
Host in California (Siddiqui et al. 1973).
Serious parasite in Utah. Severe stunting follows attach
of young, succulent roots. Heads bore substandard grain numbers.
Associated with severe smut attack (Thorne 1961).
Xiphinema americanum
Host in commercial crops in California (Siddiqui et al. 1973).
BECHMANNIA SYZIGACHNE(sloughgrass)
Meloidogyne naasi
Host (Jensen et al. 1968).
BOUTELOUS CURTIPENDULA (side-oats, grama)
Tylenchorhynchus claytoni
Pathogenic (Bernard et al. 1998).
BOUTELOUS GRACILIS (side-oats, grama)
Xiphinema index
Associated (Norton et al. 1984).
BRACHYPODIUM SPP. (false brome)
Heterodera avenae
Host; can maintain populations between cereal crops
(Williams and Siddiqi 1972)
BROMUS INERMIS (smooth bromegrass)
Meloidogyne spp.
Host for all major Meloidogyne spp. (Cook and Yeates 1993).
Meloidogyne hapla
In pots, Manchar was not susceptible, and 0/3 inoculated
plants were infected (Faulkner and McElroy 1964).
Meloidogyne chitwoodi
Good host (Griffin et al. 1984).
Reproduces (Bernard et al. 1998).
Pratylenchus penetrans
In pots, initial populations of 33/100 g soil resulted in
40/g root and moderate necrosis on Smooth Saratoga after 3 months
(Miller 1978).
Pratylenchus neglectus
Reproduced well (Townshend and Anderson 1976).
BROMUS MOLLIS (Soft chess)
Criconemella xenoplax
In pots after senescence, Rf 0.53 from initial population
of 33/100 cm3 soil on cv. "Blando" (Zehr et al. 1990).
BROMUS TECTORUM (downy brome, downy chess)
Meloidogyne chitwoodi
In pots, trace reproduction: very poor host (O'Bannon et
al. 1984).
Meloidogyne hapla
In pots, non-susceptible, and 0/3 inoculated plants were
infected (Faulkner and McElroy 1964).
BROMUS SPP. (Brome, unspecified)
Heterodera avenae
Host; can maintain populations between cereal crops
(Williams and Siddiqi 1972)
CENCHRUS INCERTUS (field sandburr)
Meloidogyne chitwoodi
In pots, no reproduction: non-host (O'Bannon et al. 1984).
CYNODON DACTYLON(Bermuda grass)
Criconemella ornata
200-400/100 cc often occur without apparent damage (R M.
Giblin-Davis, pers. comm.).
The mininum number in turf in Florida that may justify
nematicide application is 500/100 cc (Dunn and Noling 1997.)
Criconemella xenoplax
In pots, after 90 days, Rf was 0.79 (common bermudagrass)
and 0.22 (coastal bermudagrass) times initial populations of
250/100 cm3 soil: non-hosts (Zehr et al. 1986).
Meloidogyne chitwoodi
In pots, trace reproduction: very poor host (O'Bannon et
al. 1984).
Meloidogyne hapla.
Can reproduce on bermudagrass (Riggs et al. 1962).
CYNODON SPP. (Bermuda grass)
Paratrichorodus minor
Pest (Cook and Yeates 1993).
DACTYLIS GLOMERATA (orchardgrass)
Criconemella xenoplax
In pots after senescence, Rf was 1.88 times initial
population of 33/100 cm3 soil on cv. Durar (Zehr et al. 1990).
D. glomerata did not suppress C. xenoplax when grown in
association with peach trees (Whittington and Zehr 1992).
In pots, after 90 days, Rf was 0.61 times initial
population of 250/100 cm3 soil: non-host (Zehr et al. 1986).
Densities were no higher than those in fallow treatments:
non-host (Lownsbery 1964).
Meloidogyne chitwoodi
In pots, moderate reproduction: moderate host (O'Bannon
et al. 1984).
Very good host (Griffin et al. 1984).
Meloidogyne hapla
In pots, Potomac was not susceptible, and 0/7 inoculated
plants were infected (Faulkner and McElroy 1964).
Meloidogyne naasi
Host for 4 US and 1 English population (Michell et al. 1973a).
Host (Franklin 1965).
Paratrichorodus minor
Pest (Cook and Yeates 1993).
Pratylenchus penetrans
In pots, initial populations of 33/100 g soil resulted in
270/ g root and moderate necrosis after 3 months (Miller 1978).
Pratylenchus neglectus
Reproduced well (Townshend and Anderson 1976).
Xiphinema americanum
In pots, 169 days after inoculation with 72/100 g soil,
the final population was 56/100 g soil (Miller 1980).
Supported densities 5 times higher than those in fallow
treatment (Lownsbery 1964).
Xiphinema bakeri
In pots, heavy damage and 360% population increase after
12 weeks (McElroy 1972).
DIGITARIA DECUMBENS (Digitgrass)
Criconemella xenoplax
In pots, after 90 days, Rf was 0.10 on Pangola and 0.06
on Transvala from initial population of 250/100 cm3 soil:
non-hosts (Zehr et al. 1986).
DIGITARIA ISCHAEMUM AND D. SANGUINALIS(crabgrasses)
Pratylenchus penetrans
Host; P. penetrans was more abundant where rye (Secale
cereale) and crabgrass (Digitaria ischaemum and D. sanguinalis)
had been grown than where buckwheat (Fagopyrum esculentum) and
pigweed (Amaranthus retroflexus) had grown the previous season.
Thereafter, P. penetrans remained high in crabgrass plots,
moderately low in buckwheat plots, and fluctuated in rye and
pigweed plots (Miller and Aherns 1969).
DIGITARIA SANGUINALIS (hairy crabgrass)
Criconemella xenoplax
In pots, after 90 days, Rf was 0.22 times initial
population of 250/100 cm3 soil: non-host (Zehr et al. 1986).
Meloidogyne naasi
Host for 4 US and 1 English population (Michell et al. 1973a).
DIGITARIA SPP. (crabgrasses)
Longidorus elongatus
Associated (Norton et al. 1984).
ECHINOCHLOA CRUSGALLE (barnyard grass or cockspur)
Criconemella xenoplax
In pots, after 90 days, Rf was 0.42 times initial
population of 250/100 cm3 soil: non-host (Zehr et al. 1986).
Meloidogyne chitwoodi
In pots, light reproduction: poor host (O'Bannon et al.
1984).
Meloidogyne hapla
In pots, Rf = 0 (Belair and Beniot 1996).
In pots, not susceptible, and 0/3 inoculated plants were
infected (Faulkner and McElroy 1964).
Xiphinema bakeri
In pots, light damage and 544 % population increase on
Danish after 12 weeks (McElroy 1972).
ECHINOCHLOA FRUMENTACEA (Japanese millet)
P. penetrans
207% increase over initial inoculum (McDonald and Mai 1963).
ECHINOCHLOA SPP. (barnyard grass)
Heterodera avenae
Host; can maintain populations between cereal crops
(Williams and Siddiqi 1972)
ELEUSINE INDICA (goosegrass)
Criconemella xenoplax
In pots, after 90 days, Rf was 0.00 times initial
population of 250/100 cm3 soil: non-host (Zehr et al. 1986).
ELYTRIGIA REPENS
See Agropyron complex.
ELYMUS CANADENSIS (wildrye)
Pratylenchus penetrans
Experimentally infected with P. penetrans (Jensen 1953).
ELYMUS CINEREUS (Great Basin wildrye)
Meloidogyne chitwoodi
Poor host (Rf = 0.1) (Griffin et al. 1984).
ELYMUS LANCEOLATUS
See Agropyron complex.
ELYMUS SIBERICUS (Siberian wildrye)
Meloidogyne hapla
In pots, not susceptible, and 0/4 inoculated plants were
infected (Faulkner and McElroy 1964).
Elymus spp.
See Pseudoroegneria spicata (bluebunch wheatgrass). (Elymus is
a synonym for Pseudoroegneria).
ELYTRIGIA INTERMEDIA (intermediate wheatgrass)
Meloidogyne chitwoodi
Nonhost (Rf = 0) (Griffin et al. 1984).
ERAGROSTIS ORCUTTIANA (lovegrass)
Meloidogyne chitwoodi
In pots, light reproduction: poor host (O'Bannon et al. 1984).
EREMOCHLOA OPHIUROIDES (Centipede Grass)
Criconemella xenoplax
Did not suppress C. xenoplax when grown in association with
peach trees (Whittington and Zehr 1992).
In pots, after 90 days, Rf was 0.12 times initial
population of 250/100 cm3 soil: non-host (Zehr et al. 1986).
FESTUCA ARUNDINACEA (tall fescue)
Criconemella xenoplax
In pots, after 90 days, Rf was 1.01 times initial
population of 250/100 cm3 soil: host (Zehr et al. 1986).
Meloidogyne chitwoodi
In pots, moderate reproduction: moderate host (O'Bannon et
al. 1984).
Meloidogyne hapla
In pots, Alta was not susceptible, and 0/3 inoculated
plants were infected (Faulkner and McElroy 1964).
Meloidogyne naasi
Reproduction and growth (Bernard et al. 1998).
Paratrichodorus minor
Host (Bernard et al. 1998).
Pratylenchus penetrans
Alta was experimentally infected with P. penetrans
(Jensen 1953).
Reproduced (Bernard et al. 1998).
FESTUCA ELATIOR (meadow fescue)
Meloidogyne naasi
Host (Radewald et al. 1970).
FESTUCA OVINA (Sheep Fescue)
Criconemella xenoplax
In pots after senescence, Rf was 0.77 times initial
population of 33/100 cm3 soil on cv. "Covar" (Zehr et al. 1990).
FESTUCA OVINA VAR. DIRIUSCULA (Hard Fescue)
Criconemella xenoplax
In pots after senescence, Rf 0.16 times initial population
of 33/100 cm3 soil on cv. "Covar" (Zehr et al. 1990).
FESTUCA PRATENSIS (meadow fescue)
Meloidogyne chitwoodi
In pots, trace reproduction: very poor host (O'Bannon
et al. 1984).
Meloidogyne naasi
N6-95 is a host for 4 US and 1 English population (Michell
et al. 1973a).
May cause failure of spring sowings, but fescues differ in
host status (Cook and Yeates 1993).
Host (Franklin 1965).
Pratylenchus penetrans
Root populations exist (Bernard et al. 1998).
FESTUCA RUBRA (red fescue)
Meloidogyne chitwoodi
In pots, light reproduction: poor host (O'Bannon et al. 1984).
Meloidogyne naasi
Host; vars. commutate (Chewings fescue), Ranier, and
Illahee are a hosts (Radewald et al. 1970).
Xiphinema americanum
In pots, 169 days after inoculation of Chewings with
72/100 g soil, the final population was 120/100 g soil (Miller
1980).
FESTUCA SPP. (fescue, unspecified)
Heterodera avenae
Host; can maintain populations between cereal crops
(Williams and Siddiqi 1972)
HORDEUM BOGDANII (wild barley)
Meloidogyne chitwoodi
Rf = 84.9 (Jensen and Griffin 1994).
HORDEUM BREVISUBULATUM (wild barley)
Meloidogyne chitwoodi
Rf = 22.9 (Jensen and Griffin 1994).
HORDEUM CALIFORNICUM (wild barley)
Meloidogyne chitwoodi
f = 0.5 (Jensen and Griffin 1994).
HORDEUM CHILENSIS (wild barley)
Meloidogyne chitwoodi
Rf = 0.1 (Jensen and Griffin 1994).
HORDEUM HYSTRIX (wild barley)
Meloidogyne naasi
Host (Jensen et al. 1968).
HORDEUM VULGARE (barley)
Heterodera avenae
Causes stunting and chlorosis, branched root systems, and
patchy growth, grain formation is inhibited (Kleynhans et al.
1996).
Host in New Zealand (Knight et al. 1997)
Longidorus elongatus
Host (Norton et al. 1984).
Causes damage (McGawley and Overstreet 1998).
Meloidogyne chitwoodi
In pots, tilleringwas was suppressed by M. chitwoodi but
was affected less than wheat by inoculum densities of 0 to
2000/eggs 100 cm3 soil. Heads/plant or head dry weight did not
correlate with inoculum level. M. chitwoodi inoculum prevented
head set of Kombar spring barley. Root weights were reduced at
all inoculum levels (Griffin 1992a).
In pots, Boyer was a suitable host (Rf = 13.4) for Race 2
(alfalfa race) (Mojtahedi et al. 1988b).
In pots, cvs. Advance, Boyer, Hesk, Klages, and Steptoe:
high reproduction: good hosts; and cvs. Kamiak, Mal, Morex,
Piroline, and Vanguard: very high reproduction: very good host
(O'Bannon et al. 1984).
At 500 and 5000 eggs/liter soil, Boyer total plant dry
weight was significantly less than uninoculated controls. M.
chitwoodi increased from 2 to 4 times on Boyer barley cultivars
(Santo and O'Bannon 1981).
In pots, Steptoe and Wocus 71 were maintenance hosts
(Rf = 1.44 and 1.31), and Briggs is a poor host (Rf = 0.29) for
race 1 (Ferris et al. 1993).
In pots, 50 J2/100 cm3 soil reduced shoot weight by 25% at
25oC but not root and head weight in Steptoe; yields were not
significantly different from uninoculated controls at 15 and 20oC (Umesh and Ferris 1994).
Yields of spring barley were reduced by 3.5% for every 1000
J2/100g, up to a maximum 50% loss at 15000/100g; winter barley
sustained less damage (Rivoal and Cook 1993).
In pots, Rf of 1.1 on Boyer from inoculation of
approximately 200/100 cm3 soil (Santo et al. 1980).
Meloidogyne hapla
In pots, not susceptible, and 0/20 inoculated plants were
infected (Faulkner and McElroy 1964).
In pots, cv. Wong is a host (Gaskin and Crittenden 1956).
In pots, Rf of 0 on Boyer from inoculation of approximately
200/100 cm3 soil (Santo et al. 1980).
Meloidogyne naasi
Trail is a host for 4 US and 1 English population (Michell
et al. 1973a).
Damages spring barley (Franklin 1973).
Where barley had been cropped continuously in California,
losses amounted to 50 to 75% of the crop (Franklin 1973).
Yields of spring barley were reduced by 3.5% for every
1000 J2/100 g soil up to a maximum 50% loss at 15,000 J2/100 g
soil; winter sown barley damage was apparently lower (Rivoal and
Cook 1993).
Tennessee winter barley is a good host (Golden and Taylor
1967).
enton and Trail are hosts; symptoms are worst in poorly
drained areas (Jensen et al. 1968).
Wocus is a host (Radewald et al 1970).
Pratylenchus spp.
Causes severe damage (Kleynhans et al. 1996).
Pratylenchus crenatus
At 500/g root in controls at harvest, yield correlated
negatively with initial population (Rivoal and Cook 1993).
Pratylenchus neglectus
150/100 cm3 soil at sowing decreased grain weight by 9% (Rivoal
and Cook 1993).
150/100 cm3 soil significantly reduced root but not shoot
or head weight at 20o C but not at 15o or 25o (Umesh and Ferris
1994).
Pratylenchus penetrans
Experimentally infected with P. penetrans (Jensen 1953).
Pratylenchus thornei
4/100 cm3 soil decreased grain weight by 10%. (Rivoal and
Cook 1993).
In pots, 42 and 420/100 cm3 soil decreased ear weight by
26 and 45 %. (Rivoal and Cook 1993).
Xiphinema americanum
Host in commercial crops in California (Siddiqui et al 1973).
HORDEUM SPP. (Barley)
Heterodera avenae
Host; can maintain populations between cereal crops
(Williams and Siddiqi 1972)
KOELERIA SPP. (Hair grass)
Heterodera avenae
Host; can maintain populations between cereal crops
(Williams and Siddiqi 1972)
LOLIUM MULTIFLORUM (Italian ryegrass)
Meloidogyne naasi
Host for 4 US and 1 English population (Michell et al. 1973a).
Pratylenchus neglectus
L. multiflorum is a host in California (Norton et al. 1984).
Pratylenchus penetrans
In pots, initial inoculum increased 50% (McDonald and Mai
1963).
Xiphinema americanum
In pots, 169 days after inoculation with 72/100 g soil,
the final population was 24/100 g soil (Miller 1980).
LOLIUM PERENNE (perennial ryegrass)
Criconemella xenoplax
Did not suppress C. xenoplax when grown in association
with peach trees (Whittington and Zehr 1992).
In pots, after 90 days, Rf was 2.17 times initial
population of 250/100 cm3 soil: host (Zehr et al. 1986).
Longidorus elongatus
Severely damaged (Hooper 1973).
Induces galls (Griffiths and Robertson 1984).
Meloidogyne hapla
In pots, not susceptible, and 0/3 inoculated plants were
infected (Faulkner and McElroy 1964).
Meloidogyne naasi
Host for 4 US and 1 English population (Michell et al. 1973a).
Host (Franklin 1965, Radewald et al. 1970).
Aldicarb applied at spring sowing of perennial ryegrass on
field plots with 3800 J2/100 cm3 soil increased first year
yields by 22%.(Cook and Yeates 1993).
In pots, 20000 J2/100 cm3 soil reduced yields by 51% after
3 months, but 6000/100 cm3 had no effect in the field (Cook and
Yeates 1993).
Pratylenchus penetrans
In pots, initial inoculum increased 37% (McDonald and Mai 1963).
LOLIUM SPP. (unspecified ryegrass)
Heterodera avenae
Host; can maintain populations between cereal crops
(Williams and Siddiqi 1972)
Pratylenchus penetrans
In pots, initial populations of 33/100 g soil resulted in
50/g root and little necrosis on Oregon ryegrass after 3 months
(Miller 1978).
PANICUM CAPILLARE (common or old witchgrass)
Meloidogyne chitwoodi
In pots, light reproduction: poor host (O'Bannon et al. 1984).
Meloidogyne hapla
Non-host (Rf = 0) (Belair and Benoit 1996).
PASCOPYRUM SMITHII (Barton western wheatgrass)
See also Agropyron compex.
Meloidogyne chitwoodi
Good host (Rf = 3.0) (Griffin et al. 1984).
PENNISETUM GLAUCUM (pearl millet)
Meloidogyne hapla
In pots, not susceptible, and 0/3 inoculated plants were
infected (Faulkner and McElroy 1964).
PHALARIS ARUNDINACEA (reed canary grass).
EXTREMELY SERIOUS WEED; CHECK WITH YOUR STATE DEPARTMENT OF
AGRICULTURE BEFORE PLANTING.
Meloidogyne hapla
In pots, not susceptible, and 0/3 inoculated plants were
infected (Faulkner and McElroy 1964).
Pratylenchus penetrans
In pots, initial populations of 33/100 g soil resulted in
50/g root and very little necrosis after 3 months (Miller 1978).
PHALARIS SPP. (canary grasses)
Heterodera avenae
Host; can maintain populations between cereal crops
(Williams and Siddiqi 1972).
Tylenchorhynchus claytoni
Pest (Cook and Yeates 1993).
Paratrichorodus minor
Pest (Cook and Yeates 1993).
PHLEUM PRATENSE (Timothy)
Meloidogyne hapla
In pots, Crummond was not susceptible, and 0/5 inoculated
plants were infected (Faulkner and McEvoy 1964).
Meloidogyne naasi
Poor host (Cook and Yeates 1993).
Pratylenchus crenatus
Survived and reproduced (Bernard et al. 1998).
Pratylenchus penetrans
In pots, initial populations of 33/100 g soil resulted in
50/ g root and very little necrosis after 3 months (Miller 1978).
Experimentally infected with P. penetrans (Jensen 1953).
Pratylenchus neglectus
Host; moderate reproduction (Townshend and Anderson 1976).
PHLEUM SPP. (Timothy)
Heterodera avenae
Host; can maintain populations between cereal crops
(Williams and Siddiqi 1972)
POA ANNUA (annual bluegrass)
Meloidogyne chitwoodi
In pots, light reproduction: poor host (O'Bannon et al.
1984).
Meloidogyne naasi
Host for 4 US and 1 English population (Michell et al.
1973a).
Host (Franklin 1965, Radewald et al. 1970, Radewald et al.
1966).
Pratylenchus crenatus
Has caused damage as a member of mixed populations (Cook
and Yeates 1993).
POA PRATENSIS (Kentucky bluegrass)
Criconemella xenoplax
In pots, after 90 days, Rf was 0.71 times initial
population of 250/100 cm3 soil (Zehr et al. 1986).
Meloidogyne chitwoodi
In pots, trace reproduction: very poor host (O'Bannon et
al. 1984).
Meloidogyne naasi
Filking is a host for 4 US and 1 English population
(Michell et al. 1973a).
Kentucky, Merion, Newport, and Park are hosts (Radewald et
al. 1970).
Host (Franklin 1965).
Tylenchorhynchus spp.
Pest (Cook and Yeates 1993).
Pratylenchus penetrans
xperimentally infected with P. penetrans (Jensen 1953).
POA TRIVIALIS (rough bluegrass)
Meloidogyne naasi
Host for 4 US and 1 English population (Michell et al. 1973a).
Host (Radewald et al. 1970).
POA SPP. (Bluegrass, unspecified)
Heterodera avenae
Host; can maintain populations between cereal crops
(Williams and Siddiqi 1972)
POLYPOGON SPP. (beard-grass)
Heterodera avenae
Host; can maintain populations between cereal crops
(Williams and Siddiqi 1972)
PSEUDOROEGNERIA SPICATA (bluebunch wheatgrass). (Pseudoroegneria is a synonym for Elymus).
Meloidogyne chitwoodi
Nonhost (Rf = 0) (Griffin et al. 1984).
Rf = 1.2 (Jensen and Griffin 1994).
SECALE CEREALE (rye)
Criconemella xenoplax
In pots, after 90 days, Rf on Wre's Abruzzi was 0.84 from
initial population of 250/100 cm3 soil (Zehr et al. 1986).
Heterodera avenae
Causes stunting and chlorosis, branched root systems, and
patchy growth, grain formation is inhibited (Kleynhans et al.
1996).
Longidorus elongatus
Host (Norton et al. 1984).
Meloidogyne chitwoodi
In pots, maintenance host (Rf = 1.07) for race 1 (Ferris
et al. 1993).
Meloidogyne hapla
In pots, not susceptible, and 0/15 inoculated plants were
infected (Faulkner and McElroy 1964).
In pots, Imperial was a host (Gaskin and Crittenden 1956).
Meloidogyne naasi
Balboa is a host for 4 US and 1 English population
(Michell et al. 1973a).
Paratrichodorus allius
Merced is a host (Norton et al. 1984).
Paratrichodorus minor
Host (Hooper 1977).
Pratylenchus penetrans
In pots, initial populations of 33/100 g soil resulted in
220/g root and moderately severe necrosis after 3 months (Miller
1978).
P. penetrans was more abundant where rye (Secale cereale)
and crabgrass (Digitaria ischaemum and D. sanguinalis) had been
grown than where buckwheat (Fagopyrum esculentum) and pigweed
(Amaranthus retroflexus) had grown the previous season.
Thereafter, P. penetrans remained high in crabgrass plots,
moderately low in buckwheat plots, and fluctuated in rye and
pigweed plots (Miller and Aherns 1969).
Pratylenchus neglectus
Host (Townshend and Anderson 1976).
Xiphinema bakeri
In pots, moderate damage and 285% population increase after 12 weeks on cv "Storm" (McElroy 1972).
SETARIA LUTESCENS (yellow or green foxtail)
Meloidogyne chitwoodi
In pots, trace reproduction: very poor host (O'Bannon et al. 1984).
In pots, moderate reproduction: moderate host (O'Bannon et
al. 1984).
Meloidogyne hapla
In pots, not susceptible, and 0/3 inoculated plants were
infected (Faulkner and McElroy 1964).
Setaria viridis (green bristlegrass or foxtail)
Criconemella xenoplax
In pots, after 90 days, Rf was 0.07 times initial
population of 250/100 cm3 soil: non-host (Zehr et al. 1986).
Meloidogyne hapla
In pots, Rf = 0 (Belair and Beniot 1996).
0 galls/g root after 50 days in pots inoculated with 3600
J2 (Townshend and Davidson 1962).
SETARIA SPP. (foxtail; German or Italian millet)
Heterodera avenae
Host; can maintain populations between cereal crops
(Williams and Siddiqi 1972)
SORGHUM BICOLOR (sorghum)
Criconemella xenoplax
On Pioneer 8333, root dry weight was reduced 20-27% by
Tylenchorhynchus annulatus. The reduction was greater (35%,
p = 0.001) when T. annulatus was combined with C. xenoplax,
although C. xenoplax alone did not reduce root weight. DK 50
plants generally were larger than those of P8333 (Wenefrida et
al. 1995, 1997).
Heterodera avenae
Host; can maintain populations between cereal crops
(Williams and Siddiqi 1972)
Longidorus elongatus
Host (Norton et al. 1984).
Meloidogyne naasi
RS-610 is a host for Kansas but not California, Illinois,
Kentucky, or English populations (Michell et al. 1973a).
SORGHUM HALPENSE (Johnsongrass)
Criconemella xenoplax
In pots, after 90 days, Rf was 0.41 times initial
population of 250/100 cm3 soil (Zehr et al. 1986).
SORGHUM SUDANENSE OR SUDAN X DRUMMONDII (Sudan grass)
Meloidogyne chitwoodi
In pots, Sudan grass (unspecified cultivar) was a is a
poor host (Rf = 0.4) for Race 2 (alfalfa race) (Mojtahedi et al.
1988b).
In pots, trace reproduction: very poor host (O'Bannon et
al. 1984).
Meloidogyne hapla
In pots, not susceptible, and 0/4 inoculated plants were
infected (Faulkner and McElroy 1964).
Meloidogyne naasi
Trudan I is a non-host (Radewald et al. 1970).
Paratrichodorus allius
Host (Norton et al. 1984).
Pratylenchus neglectus
Host in California (Siddiqui et al 1973).
Pratylenchus penetrans
In pots, initial populations of 33/100 g soil resulted in
40/ g root and very severe necrosis after 3 months (Miller 1978).
Sorghum spp. and their hybrids are possible rotation crops
for suppression of P. penetrans in potato production (Cook and
Yeates 1993).
In pots, 23% increased of initial inoculum (McDonald and
Mai 1963).
Pratylenchus thornei
Host in California (Siddiqui et al. 1973).
Xiphinema americanum
In pots, 169 days after inoculation of Sudanese with
72/100 g soil, the final population was 0/100 g soil (Miller
1980).
Associated with commercial crops in California (Siddiqui
et al. 1973).
SPARTINA SPP. (Cordgrass)
Trichodorus obscurus
Host (Norton et al. 1984).
THINPYRUM INTERMEDIUM
See Agropyron complex.
TRITICUM AESTIVUM (bread wheat); T. turgidum: (durum group)
Criconemella xenoplax
Populations were lower in Stacey plots than in non-
fumigated peach plots after three years (peach is a good host)
(Nyczepir and Bertrand 1994).
In pots, after 90 days, Rf on Coker 6815 was 0.25 from
initial population of 250/100 cm3 soil (Zehr et al. 1986).
Heterodera avenae
Causes stunting and chlorosis, branched root systems, and
patchy growth, grain formation is inhibited (Kleynhans et al.
1996).
Host in New Zealand (Knight et al. 1997)
Longidorus elongatus
Host (Norton et al. 1984).
Meloidogyne chitwoodi
In pots, Nugaines was a maintenance host for race 1. In
field trials, population levels on Russet Burbank were
significantly higher following wheat cv. Fieldwin and Austrian
winter peas and fallow than following other crops. (Ferris et
al. 1993).
In pots, tillering, heads/plant, head length, and dry
weight were negatively correlated with inoculum level (from 0 to
2000/100 eggs cm3 soil). The greatest plant height reduction
was at 2000/100 cm3 soil. Head development was reduced on
spring cultivars Fremont, Twin, Borah, and Fielder. Winter
cultivars Nugaines and Wanser were better hosts for the Utah
population than were Manning, Dusty, or Daws (Griffin 1992a.)
In pots, Fielder (spring) was a suitable host (Rf = 36.8)
for Race 2 (alfalfa race). Nugaines (winter) (Rf = 17.3) is a
is a suitable host for Race 2 (alfalfa race) (Mojtahedi et al.
1988b).
In pots, the relationship between top dry weight and
initial nematode density suggests a tolerance limit for Nugaines
wheat of between 3 and 18 eggs/100 cm3 soil at planting;
tolerance in February was greater than tolerance in April.
Nugaines withstood up to 900/100 cm3 soil with no effect on
yield. In microplots, yield of Fielder spring wheat was
decreased by 41% and 73% by 75 and 900 eggs/100 cm3 soil,
respectively. M. chitwoodi reproduced on cvs. Fielder,
Fieldwin, Hyslop, Gaines, and Nugaines, but fewer eggs were
recovered from Gaines and Nugaines, confirming that Nugaines is
a poor host compared to Fielder (Nyczepir et al. 1984).
In pots, spring wheat cvs. Borah, Dirkwin, Fielder,
Fieldwin, Owens, Sawtell, Sterling, and Twin: very high
reproduction: very good hosts. Cv. Twin: high reproduction:
good host. Winter wheat cvs. Faro: moderate reproduction,
moderate host. Cv. Barbee, Hylsop, Luke, Moro, Neeley, Palouse,
Tyee, and Wanser: high reproduction, good hosts. Cvs. Nugaines, Prodax, and Stephens: very high reproduction, very good hosts (O'Bannon et al. 1984).
At 500 and 5000 eggs/liter soil, Wanser wheat total plant dry
weight weighed significantly less than uninoculated controls.
Roots but not top growth of Prodax and Nugaines weighed less
than uninoculated controls. M. chitwoodi increased from 11 to
65 times on wheat cultivars (Santo and O'Bannon 1981).
Meloidogyne hapla
Cvs. Fielder, Fieldwin, Hyslop, Gaines, and Nugaines are
not hosts (Nyczepir et al. 1984).
In pots, Omar winter wheat and Federation, Marfed, and
Pilcraw spring wheat were not susceptible, and no plants
inoculated were infected (Faulkner and McElroy 1964).
In pots, cvs. "Thorne", "Nured", and "Seneca" were not
hosts (Gaskin and Crittenden 1956).
Meloidogyne naasi
Damages spring wheat (Franklin 1973).
Pawnee is a host for 4 US and 1 English population
(Michell et al. 1973a).
amona 50 is a host (Radewald et al. 1970).
Paratrichodorus allius
ar. vulgare is a host (Norton et al. 1984).
Trichodorus obscurus
ost (Norton et al. 1984).
Pratylenchus spp.
Causes severe damage (Kleynhans et al. 1996).
Pratylenchus crenatus
Associated with yellowing and stunting of wheat (Kleynhans
et al. 1996).
Pratylenchus neglectus
Relatively weak pathogen on Stephens wheat (Mojtahedi and
Santo 1992).
Host in California (Siddiqui et al 1973).
Associated with yellowed and stunted patches of plants in
wheat fields during spring in southrn Ontario, Canada.
(Townshend and Anderson 1976).
Pratylenchus thornei
0 to 100/100 cm3 soil (Rivoal and Cook 1993).
In pots, 667/100 cm3 soil caused stunting and chlorosis on
"Stephens". 67/100 cm3 caused no noticeable damage (Mojtahedi
et al. 1988).
Associated with wheat exhibiting unthrifty patches and
stunted and chlorotic growth, sometimes in low spots, and in
Madsen wheat with intermittent yield problems, in SE Washington
(W. T. Cobb, pers. comm., 1997).
In Mexico, on wheat cultivars Tobari and Inia, 42, 420,
and 4,200 P. thornei/100 cc soil reduced heat weight 26, 45, and
34%, respectively, after 60 days. Yields of cultivars Inia,
Tobari, Azteca, Norteno, Lerma Rojo, and Siete Cerros on
fumigated soils were from 19 to 30% higher than yields on soils
with 173-229 P. thornei/100 cm3 soil (Van Gundy et al. 1974).
Probably reduces yield in wheat grown during relatively
dry seasons and in soil with a relatively high nematode
population at seeding (Baxter and Blake 1968).
Serious parasite in Utah. Severe stunting follows attack
of young, succulent roots. Heads bore substandard grain numbers
(Thorne 1961).
Xiphinema americanum
Associated with commercial crops in California (Siddiqui
et al. 1973).
VULPIA SPP. (Annual fescue)
Heterodera avenae
Host; can maintain populations between cereal crops
(Williams and Siddiqi 1972)
ZEA MAYS (corn, maize)
Heterodera avenae
May be severely damaged by invading J2, but the life cycle
is not completed. Heavy infestations result in root death, and
new roots are subsequently invaded (Dropkin 1980).
May be damaged when heavily infested (Kleynhans et al 1996).
Corn is sometimes attacked, but it is not usually a good
host (Williams and Siddiqi 1972).
Longidorus elongatus
Rugosum is a host (Norton et al. 1984).
Meloidogyne spp.
Species other than M. hapla usually decrease under corn
(Baldwin and Barker 1970).
Meloidogyne chitwoodi
In pots, Idahybrid 303, Northrup King 497, and Pioneer
3232 were suitable hosts (Rf = 12.1, 6.9, and 8.6) for Race 2
(alfalfa race) (Mojtahedi et al. 1988b). Idahybrid 303 and
Northrup King 497 were suitable hosts (Rf = 6.5 and 2.2) for for
Race 1 (non-alfalfa race) (Mojtahedi et al. 1988b).
In pots, cv. Northrup King 497: trace reproduction, very
poor host. Cvs Cenex 2119, Funks G4574, JX 122A, JX 1153, and
Northrup King PX 46: moderate reproduction, moderate hosts.
Cvs. Funks G-4444 MF, Idahybrid 216, and Northrup King 589:
high reproduction, good hosts (O'Bannon et al. 1984).
At 500 and 5000 eggs/liter soil, PX 46 total plant dry
weight was significantly less than controls; Jubilee root weight
but not dry weight dry weight was not reduced. M. chitwoodi
reproduced but did not increase on PX 46 and Jubilee (Santo and
O'Bannon 1981).
In pots, Rf of 1.9 on PX 46 from inoculation of
approximately 200/100 cm3 soil (Santo et al. 1980).
Meloidogyne hapla
Does not reproduce on corn (Baldwin and Barker 1970,
Sasser 1966).
In pots, Dwarf, Medium Hat 354, and Nestam 101 were not
susceptible, and no inoculated plants were infected (Faulkner
and McElroy 1964).
In pots, Rf of 0 on PX 46 from inoculation of approximately
200/100 cm3 soil (Santo et al. 1980).
Meloidogyne naasi
Non-host (Radewald et al. 1970).
Paratrichodorus allius
Host (Norton et al. 1984).
Pratylenchus spp.
Moderately damaged (Kleynhans et al. 1996).
Pratylenchus crenatus
Recorded (Kleynhans et al. 1996).
Pratylenchus neglectus
Recorded (Kleynhans et al. 1996).
Host in California (Siddiqui et al 1973).
Pratylenchus penetrans
In pots, 25/100 cm3 soil significantly reduced root growth
at 20 and 24 but not 16 and 28o C and top growth at 20o C only;
stem diameter was not reduced (Dickerson et al. 1964).
In pots, initial populations of 33/100 g soil resulted in
70/g root and little necrosis on "Butter and Eggs" after 3
months (Miller 1978).
Pratylenchus thornei
Associated with corn in Wisconsin (Norton et al. 1984).
Serious parasite in limited areas of Salt Lake County,
Utah; associated with severe smut infestation (Thorne 1961).
Xiphinema americanum
On Funk's G4444 Hybrid, X. americanum populations reached
maxima of about 15 to 55 from early August through early
September and minima of about 1 to 4 from April through July.
Densities were greater in no-till ridge plots. Densities in
till-plant plots were greater than those in fall-plowed plots
Thomas 1978).
Cv. A619Ht X A632Ht is a host (Norton and Edwards 1988).
In pots, 169 days after inoculation of an unspecified
cultivar with 72/100 g soil, the final population was 0/100 g
soil (Miller 1980).
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