Poster Session: Diseases of Plants - Disease Detection and Diagnosis

59-P

The stem nematodes of Ditylenchus weischeri and D. dipsaci can be reared on carrot disks but not on fungal cultures.
A. HAJIHASSANI (1), M. Tenuta (1)
(1) University of Manitoba, Winnipeg, MB, Canada

Monoxenic cultures can provide sufficient amount of nematode inoculum in studying plant-nematode associations. Among species of Ditylenchus, some have been reared on callus of alfalfa, chicory or carrot as well as fungal cultures. A population of D. weischeri from creeping thistle in Manitoba and D. dipsaci from garlic in Ontario were examined for potential to be reared on carrot disks and fungal cultures. The nematodes were isolated from plant tissues, placed in streptomycin sulphate (4,000 mg L-1) and repeatedly rinsed in sterile distilled water. Eighty individuals (male, female and J4) of each species were then transferred to plates containing either surface sterilized carrot disks without nutrient agar or the fungi, Fusarium solani, Botrytis cinerea, Rhizoctonia solani, Verticillium dahliae, Sclerotinia sclerotiorum, Colletotrichum gloeosporioides, and an unidentified species from creeping thistle, cultured on PDA. The number of nematodes recovered from carrot disks varied significantly for the two species. The number of D. weischeri increased 51 times, however, the number of D. dipsaci increased more, being 238 times. D. weischeri and D. dipsaci couldn’t be reared on any of the fungal isolates examined. The results indicate feeding behaviour of D. dipsaci and D. weischeri is different from other Ditylenchus species capable of rearing on fungi. Rearing both nematode species on carrot disks will provide large numbers of individuals for plant host range studies.