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Dolichodorus heterocephalus Cobb, 1914
The genus Dolichodorus was erected by Cobb ( 1914) when he
named D. heterocephalus from fresh water at Silver Springs, Florida and
Douglas Lake, Michigan.
Length, female: 2.1-2.7 mm; length, male: 1.7-2.2 mm.
[Ref: CIH Descriptions of Plant-parasitic Nematodes,
Set 4, No. 56 (1974)]
Drawing from Cobb, 1914
Source: CIH Descriptions of Plant-parasitic Nematodes, Set 4, No. 56 (1974)
Eastern U.S., especially Florida (wet areas); also in virgin soil in South Africa, Zimbabwe (Julbernardia - 7 ft. below soil surface near water table, although species unconfirmed).
Cranberry bogs in Massachussetts.
Related genus Neodolichodorus occurs in wet areas of Napa Valley and Coastal range, for example a citrus tree near a well in Yountville, on a bay tree next to a stream near Lake Berryessa.
A-rated pest in California.
Ectoparasite mainly at root tip; nematode has long stylet.
Celery, sweet corn, water chestnut, bean, tomato, pepper, cranberry, cabbage, balsam, and carnation.
For an extensive list of host plant species and their susceptibility, copy the name
select Nemabase and paste the name in the Genus and species box
Nematode prefers wet locations with high soil moisture.
Field infestations in Florida may be due to soil spreading from riverbanks onto fields and into irrigation water (Christie, 1959).
Males and females are both present.
Life history parameters not well known. Paracer et al. (1968) gives some information on the biology of Massachusetts populations: the first larval molt occurs in the egg; second stage juveniles hatch after 14-17 days at 20-23 C.
Males, females, and all larval stages feed, individuals sometimes remaining at one location on the root for up to 7 days.
The nematode does not survive in fallowed pots for longer than 3 months.
Several different biotypes of D. heterocephalus may be present (Florida and Massachusetts populations) (Paracer et al., 1968); they are distinguished by the host status of celery to them.
Feeding causes brownish cortical lesions and enlarged cortical nuclei; root elongation ceases; secondary roots are attacked, resulting in stubby-root symptoms; some terminal galling may be observed.
Perry (1953) observed severe stunting, accompanied by depleted root systems of celery and corn, in field infestations of D. heterocephalus in Florida. Celery yield was reduced by 50% in one field.
Water chestnut growing in hydroponic beds was also stunted; nematode feeding
also causes stunting of tomato, bean, and pepper (Perry, 1953).
Use of nematicides, such as 1,3-Dichloropropene (Telone) or, earlier, ethylene dibromide (EDB).
Drying of moist soil areas gives effective control.
[Would dry fallow for at least 3 months also be effective under field conditions?]
Host Plant Resistance, Non-hosts and Crop Rotation alternatives:
For a list of plant species or cultivars (if any) reported to be immune or to have some level of resistance to this nematode species, copy the name
select Nemabase Resistance Search and paste the name in the Genus and species box
CIH Descriptions of Plant-parasitic Nematodes, Set 4, No. 56 (1974)
Cobb, N.A. 1914. The North American free-living fresh-water nematodes. Transactions of the American Microscopical Society, 33: 69-133.