Paratylenchus hamatus Thorne and Allen, 1950
Females: Gravid female may
swell anterior to vulva.
Strong stylet, usually about 36 Âµm.
single, prodelphic, outstretched.
Vulva a transverse slit with lateral membranes which may extend
inward over the vulval opening. In other literature these are
referred to as advulval flaps (Ghaderi et al., 2014).
Reported median body size for this species (Length mm; width micrometers; weight micrograms) - Click:
Europe and North America.
Widely distributed in California, but not usually found in cooler
Originally described from fig in soil samples taken by E.F. Serr near Planada,
California (11 miles west of Merced) and sent to Gerald Thorne in Salt Lake City
for diagnosis. From those samples,
Thorne and Allen
(1950) described both Xiphinema index and
Paratylenchus hamatus is apparently the most common
species of pin nematode in woody perennials of California (Raski, 1975).
occur in abundance in vineyards free of other vegetation, but it is not
associated with vine damage except when young grapevines have been planted into
very high population levels.
Highest population levels of this nematode are
often measured on the most vigorous vines and its presence appears to slow the
build-up of other endo- and ectoparasites (Ferris and McKenry, 1975; Ferris et
Feeding of large numbers produced shallow, localized lesions on
grape roots (Raski and Radewald, 1958).
Celery, figs, grapes, and peaches in the San Joaquin Valley of
It does not occur on Juglans spp.
Similar to P. neoamblycephalus, but has a different host range and
there are differences in the life cycle of the male.
Associated with crop decline in figs (Thorne and Allen,
1950), but a positive correlation
with vigor has been observed in grape and peach (Ferris and McKenry). McKenry
has suggested that P.hamatus may have an antagonistic or competitive
xenoplax - in field experiments
(1998-90) soil around peach roots was inoculated with P. hamatus after
fumigation, but results were not convincing.
This nematode also causes damage to celery in North Eastern U.S.
and the Netherlands; can also deform carrots.
Plant weights of mint may be reduced and flowering
delayed by P. hamatus infestation in the Yakima Valley of Washington
(Ingham and Merrifield, 1996).
In pot experiments, dry weights of peppermint and
scotch spearmint plants 22 weeks after inoculation were reduced 20%-34%.
Infected plants remain succulent longer which renders them susceptible to winter
injury (Faulkner, 1964).
In tall fescue grass, tillering was increased but
top growth is stunted (Coursen and Jenkins, 1958).
Tops of celery attacked by pin nematodes can
become stunted and chlorotic (Lownsbery et al., 1952). Figs infected by pin
nematodes become chlorotic with undersized fruit (Thorne and Allen, 1950).
Host Plant Resistance, Non-hosts
Coursen, B.W. and W.R. Jenkins. 1958.
Host-parasite relationships of the pin nematode, Paratylenchus projectus
on tobacco and tall fescue. Plant Disease Reporter 42:865-872.
Faulkner, L.R. 1964. Pathogenicity and population
dynamics of Paratylenchus hamatus on Mentha species.
Merrifield, K. 1996. A Guide to Nematode Biology and Management in
Mint. Integrated Plant Protection Center, Oregon State University,
Corvallis. Pub. No. 996. 38 p.
Lowensbry, B.F., E.M. Stoddars and J.W. Lownsbery.
1952. Paratylenchus hamatus pathogenic on celery. Phytopathology
Raski, D.J. 1975. Revision of the Genus Paratylenchus Micoletzky, 1922 and
Descriptions of New Species. Part II of Three parts. J. Nematology 7
Raski, D.J., Radewald, J.D. 1958. Symptomology of
certain ectoparasitic nematodes on roots of Thompson seedless grape. Plant
Disease Reporter 42:941-943.
Thorne, G. and M.W. Allen. (1950)
Paratylenchus hamatus n. sp.
and Xiphinema index n.sp., two nematodes associated with fig roots, and a
note on Paratylenchus anceps. Proc. Helminth. Soc. Wash 17:27-35.