ARS | Publication request: DEVELOPMENT OF STATEGIES TO EVALUATE BRASSICA OLERACEA L. VEGETABLE CROPS FOR WIRESTEM CAUSED BY RHIZOCTONIA SOLANI

Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: August 1, 1996
Publication Date: N/A

Technical Abstract: Wirestem, caused by Rhizoctonia solani, is a destructive disease of B. oleracea cole crops. Wirestem is controlled by soil fumigation and soil treatment with pentachloronitrobenzene, which are increasingly expensive and environmentally undesirable. Thus, alternative methods of wirestem control are needed. We conducted growth chamber and field experiments to develop methodology to study host-plant resistance and possible biocontrol agents as potential wirestem control alternatives. Seedlings of cultivars (three each of cauliflower, broccoli, cabbage, and collard) were transplanted to trays in a growth room or into field plots and covered with soil infested with AG-4 R. solani sclerotia. Disease progression was observed every three days for two weeks in the chambers and for three weeks in field trials. At the end, plants were dug and rated for disease using a 1 to 10 scale. In all trials, percent healthy plants stabilized at about two weeks after inoculation. Incidence of disease varied among experiment ranging from 70-100% diseased and dead plants in growth chambers, and from 51-88% and 33-65% in two field studies. Genotype by environment interaction was observed, but some cultivars (e.g. 'Snowcone' cauliflower) were always severely diseased, while others (e.g. 'Blue Max' collard) were consistently among the least diseased.