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Hemicycliophora arenaria Raski
Hemicycliophora arenaria was described by Raski (UC Davis), extensively researched by Van Gundy (UC Riverside).
Female and all juvenile stages have sheath; also sloping stylet knobs.
Males are rare, have degenerate esophagus and no stylet or sheath.
First reported from the Coachella Valley of California on rough lemon
rootstock (Citrus jambhiri).
A-rated pests in California.
Second and third juvenile stages must feed to develop.
Males have no stylet and do not feed.
Feeding Mechanism: stylet is inserted 2-3 cells deep - through and between cells. Dorsal esophageal gland secretions pass into food cell during 1-2 hour quiescent period; then cell contents are withdrawn over period of 2-6 days during which there is regular pumping of median bulb.
The nematode has a feeding tube similar to Trichodorus
polysaccharide tube) which becomes firmly attached to root, and nematode has to writhe and twist to detach. Nematodes may appear as a fringe around root tip.
Nurse cells increase in volume, and walls thicken; some cells are multinucleate. Cells collapse when depleted and are pushed to the surface by meristem activity, thus providing a continuous supply of new food cells for the nematode.
Root-tip galls are formed by increase in cell divisions (hyperplasia), giving
rise to enlarged cortex.
Citrus, tomato, beans, celery, squash, pepper, and Tokay grape.
Also Hymenoclea salsola (cheesebush) and coyote melon (Cucurbita palmata) on virgin desert soil.
Non-host crops include "Thompson Seedless" grape, cotton, and corn.
rootstocks include trifoliate orange, sweet orange, sour orange,
and Marsh grapefruit.
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
Greenhouse tests - 36% growth reduction in citrus and 28% in tomato.
Use trifoliate orange rootstocks in citrus.
Methyl bromide applied at rate of 200lb/acre eradicates nematodes to soil depth of 3 ft.
DBCP was used at rate of 2 to 4 gal/acre in 6 inches of water to kill 98.7 to 100% of the nematodes in the top 5 ft. of soil.
Hot water treatment of bare-root trees (10 min. at 46 C.) effective.
|Hemicycliophora arenaria is sensitive to reduced aeration, and mortality periods are associated with irrigation. Fewer nematodes are observed in summer when more water is applied; higher summer temperatures may also reduce numbers, although nematode is able to flourish at 30 C.|
|Van Gundy and students observed that frequent irrigation (saturated soil conditions) kept populations at lower levels.|
Note: In 1992, attempts to find H. arenaria in the Coachella grapefruit orchard in which Van Gundy worked have been unsuccessful. There have been annual applications of the nematicide Nemacur (phenamiphos) to the orchard.
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
Van Gundy, S.D. and S.D. McElroy 1969. Sheath nematode: its biology and control. Proc. 1st Int. Citrus Symp. 2:985-989.