Tylenchorhynchus claytoni Steiner, 1937
Length, female: 0.64-0.73 mm; length, male:
Body cylindroid, only weakly curved
ventrally when relaxed.
Cuticle about 1.5 Âµm thick, with coarse
transverse striae about
2 Âµm apart, increasing to 2.9 Âµm on distal part of female tail.
with 4 longitudinal lines. Apart from these, the cuticle bears 23-29
longitudinal striae, giving it a
Lip region rounded, offset by slight constriction, composed of 3-4 annules.
Labial sclerotization weak.
Stylet slender with round basal knobs.
Orifice of dorsal esophageal gland less than 2 Âµm behind spear base.
Median bulb oval;
its valve located halfway along esophagus.
Isthmus long and narrow, terminal bulb pyriform, with conspicuous dorsal
gland nucleus; other gland nuclei not observed. Esophago-intestinal
valve small, hemispheroid.
opposite posterior end of isthmus.
annules long, located immediately anterior to excretory pore.
Vulva a transverse slit. Vagina less than one-half body width
Diovarial, amphidelphic, ovaries outstretched; uteri spacious; spermathecae
almost round, 10-13 Âµm in diameter, filled with sperm; ovaries consisting of
single row of oocytes, except for a short zone near the blind end.
Rectum about one-half the anal body width long.
Tail tapering regularly
to large, rounded, smooth terminus.
Phasmids opening in anterior
fourth of tail.
single, outstretched. Spicules
curved, with offset capitulum and acute tip. Gubernaculum
large, distinctly curved proximally. Bursa well developed, enveloping
tail, with transverse cuticular striae.
Phasmids opening in anterior
third of tail.
[Ref: CIH Descriptions of Plant-parasitic Nematodes, Set 3, No. 39 (1974)]
Reported median body size for this species (Length mm; width micrometers; weight micrograms) - Click:
Eastern U.S.; also found in Canada, Denmark, Netherlands, and Japan.
In the southeast US, azaleas are susceptible to damage by T. claytoni.
Leaves turn yellow and plants are stunted and gradually die. They fail to
respond to fertilizer and water.
Ectoparasite on epidermal cells between root
hairs in zone of elongation.
Turf, potato, tobacco, corn, wheat, oats, azaleas, trees in tree
In addition to hosts listed, Krusberg [Phytopath.
46:18 abstr. (1956)] showed that Sudan grass and Irish potato
(4400 to 6400 nemas per pot) were good hosts.
Poor hosts included Crotalaria spectabilis, peanut, pepper, cucumber, and mustard (15 to 90 nemas per pot).
About 39 days at 24 C. Males are common and are necessary for
reproduction. Maximum reproduction rates occur at 90 degrees F
(highest temperature studied); range is from 65 to 90 degrees F.
From 1 to 15 eggs per day are laid 8 to 10 days after the last molt. The
first molt occurs inside the egg.
The sexes can be recognized in the third juvenile stage by the
Nematode can survive at least 10 months in the absence of a host.
Causes damage to young corn in North Carolina [Nelson, 1956], but older
plants can tolerate larger populations; lines were selected which were resistant
to T. claytoni. Evidence from pot culture indicates changes in size and
shape of nuclei in corn roots.
In the 1950s, Graham reported 67% of 175 collections in tobacco
fields in South Carolina were infested and plants stunted. Pathogenicity
tests positive on tobacco roots stunted; no lesions. Results were
confirmed in pot tests, but researchers used small pots which may have
caused additional plant stress [Phytopath. 46: 12-13 (1954)].
Mountain [Can. J. Bot. 32:737-759 (1954)] in Canada observed T. claytoni
attacking wheat and oats, but not tobacco.
In Wisconsin and California, this species was found to injure azaleas [Sher,
Nematicides are effective; ethylene
was better than D-D
mixture for control.
(1,3-D), and Aldicarb
have also been used for control.
Host Plant Resistance, Non-hosts
CIH Descriptions of Plant-parasitic Nematodes, Set 3, No. 39 (1974)
Hodges, C.S. 1962. Diseases in southeastern forest nurseries and their
control. Station Paper 142./