Type species of the genus
Stylet very short and delicate.
Glandular region of
esophagus abutting intestine.
Female monovarial, prodelphic.
Races or biotypes are morphologically similar.
Reported median body size for this species (Length mm; width micrometers; weight micrograms) - Click:
Cosmopolitan, especially in temperate regions where it is one of the most
devastating plant parasites.
In the western US, nematode populations can be dispersed by annual transport
and migration of sheep from Colorado and Utah, although the nematode does not
appear to pass through the gut alive. Probably also associated with hay
moved with sheep.
Sources of infestation
Spread to new areas
Spread within fields
pest in California Nematode Pest
Dieback and wilting of foliage in ornamental Phlox from many parks in
Japan causes causing significant commercial losses by reulting in reductions
in the thousands opf visitors who visit the area in the Spring (Ikuyo et
Nematode is a
At the beginning of the crop season, 4th-stage juvenile enters young
tissues, especially seedlings when below the soil surface.
Feeding breaks down middle lamellae; nematode probably secretes a
pectinase enzyme; plant parts become "crisp" and are easily
Migration on plant parts above ground requires free water, and may
occur after rain or sprinkler irrigation in alfalfa.
Nematode enters through stomata or by direct penetration.
Foliar dieback in Phlox subulata in Japan (Ikuyo et al.,
Over 450 hosts for genus, but 8-10 host races or biotypes, some with
limited host range.
Oat race: polyphagous on
cereals, most grains, rye, corn, and oats.
Alfalfa race: rather specific
on certain legumes, but alfalfa, many weeds, clovers.
Bulb race: most bulbs,
daffodil, narcissus, and tulip.
Other hosts of D. dipsaci
include onion, garlic, carrots, peas, potatoes, strawberry, sugarbeets; and
various weed species.
Monovarial, prodelphic, sexually reproducing.
Life cycle is 19-23 days at 15 C.
Nematodes live 45-75 days when sexually mature; females each produce 200-500
Fourth stage juvenile (J4) is survival stage; it can enter a state of
cryptobiosis (literally "hidden life") on or below surface of plant
tissue - "eelworm wool" - 3-5 years survival (up to 23 years in museum
specimens). Survives in soil without host for as long as 2
years, probably feeding on fungi.
Plants become distorted and stunted; infected tissues are spongy; damage can
predispose plants to other problems.
Infestation occurs readily in heavier soils and during times of high
rainfall or in sprinkler-irrigated areas.
Field shows irregular areas of sparse growth.
Clover and alfalfa show reduction of internode length and swollen
Nematode is spread around field by equipment, irrigation;
spreads readily in tail water.
Stand reductions up to 50% following high fall populations.
Predisposes alfalfa to Phytophthora megasperma.
Bloated, twisted, swollen leaves, distorted and cracked bulbs.
In garlic, infestation can become epidemic.
The nematode was introduced into Venezuela in Mexican varieties of
garlic; up to 90% crop loss can occur.
Cloves are infected through to the center where leaf primordia are
located; therefore, treatment is difficult without affecting
In 1999, growers in Kern County, California, bought
garlic "seed" (cloves) from a nursery in Nevada. The seed had not
been heat treated because the nursery had not seen stem nematode in
several years.. The growers sustained devastating crop losses and
the nursery was sued for $25 million. The nursery had liability
insurance through a large company but that company sold the policies to
several smaller companies. As of November 1999, the smaller
companies were demanding that every field from which losses were
reported be sampled to demonstrate the presence of D. dipsaci.
That proved possible since there was garlic plant residue present in all
symptoms on winter Barley by Chris Hogger (Switzerland).
Leaves distorted, yellowish swelling (Dutch call it "Spikkels"- see
symptoms on garlic leaves), bulbs with dark rings.
In some plant species, inflorescence becomes infested, and pests are spread
in the seed, e.g., beans, clover, and alfalfa; infestation can also be spread by
Damage to plants
Signs and symptoms of damage
Components of crop loss
Photographs by Chris Hogger, Switzerland. Effect of
Ditylenchus dipsaci on growth (left), tap-root rot (above).
Extracts from correspondence with Dr. Sikora, University
of Bonn, April 2003:
Losses can reach a level in which the total field is plowed under. The
nematode is reproducing in the beets after harvest and moving through the
piles of beets at the factories. The farmers and sugar beet factories are
in an uproar. No one has worked on it here in Europe for ages.
effective for dormant bulbs - narcissus - 44-45 C for 3 hours, but may be
ineffective for many other crops.
Hot water harmful to tulips, so cold water with addition of pesticide (e.g.,
thionazin) is recommended.
Hot water can be used for onions and garlic; formalin no longer used
(banned), so Dr Westerdahl
and others are refining procedures - see label.
Also, water immersion of garlic cloves activates nematodes, which emerge;
then follow with gutathion treatment - cost effective.
Systemic insecticides applied at very low rates (1 lb/acre) are also
alfalfa varieties include Washoe, Lahontan and Archer (Hafez, 1998).
In Europe, resistant varieties of cereals are grown.
Host Plant Resistance, Non-hosts and Crop Rotation alternatives:
fumigation is usually not economical.
Quarantines have been required in England and Holland to control spread of
Castillo, P., Vovlas, N., Azpilicueta, A., Landa, B. B., and Jimenez-Diaz, R. M.
2007. Host-parasite relationships in fall-sown sugar beets infected by the stem
and bulb nematode,
Plant Dis. 91:71-79.
Hafez, S. 1998. Fighting nematodes in alfalfa. UC Davis
Ikuyo, Y., Kabir, M.F., Ozawa, S., Koike, Y., Ishiguro, H. and Hasegawa,
K. 2018. Characterisation and pathogenicity of Ditylenchus dipsaci isolated
from Phlox subulata in Japan. Nematology 20:811-814.
Lucas, G.B. 1986. Plant-parasitic nematodes that attack tobacco. In
Plant-Parasitic Nematodes of Bananas, Citrus, Coffee, Grapes and Tobacco. Union
Carbide Agricultural Products Inc.
Vovlas, N., Melillo, V.A., Catalano, I. 1993. Ditylenchus dipsaci, causal
agent of severe damage in celery crops in Apulia (Southern Italy).
Nematologia Mediterranea 21:55-57.