Submitted to: Northeast Potato Technology Forum Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: February 1, 2004
Publication Date: April 1, 2004
Citation: Larkin, R.P., Griffin, T.S. 2004. Brassica crop rotations for control of soilborne potato diseases. Northeast Potato Technology Forum Abstracts. 2004: 37-38 Technical Abstract: Crops in the Brassicaceae family, which include broccoli, cauliflower, turnip, radish, canola, rape, and various mustards, produce sulfur compounds that break down in soil to yield compounds that are toxic to many soil organisms, and have been used to reduce soilborne populations of fungal pathogens, nematodes, and weeds. In these studies, we evaluated selected Brassica rotation crops for their ability to inhibit multiple soilborne potato pathogens in vitro, reduce soilborne pathogens and disease development in greenhouse trials, and reduce soilborne disease in on-farm field trials. Macerated leaves from a high-glucosinolate Chinese mustard (B. juncea) significantly inhibited growth of the potato pathogens R. solani, P. erythroseptica, P. ultimum, S. sclerotiorum, F. sambucinum, and F. oxysporum in culture (60-100% inhibition). Turnip, rapeseed, canola, and, surprisingly, barley also inhibited most pathogens, although to a lesser extent (15-50%). In greenhouse trials, all Brassica crops, including canola, rapeseed, oilseed radish, turnip, yellow mustard, and chinese mustard, reduced inoculum levels of Rhizoctonia solani (20-65% reduction) relative to a potato crop, and radish, rapeseed, and chinese mustard reduced subsequent potato seedling disease by 30-85%. In on-farm trials at sites with substantial disease problems, chinese mustard, rape, and canola grown as a green manure rotation crop reduced powdery scab by 15-40% and black scurf by 50-85%, and Chinese mustard reduced common scab by 25% in the subsequent potato crop relative to a standard oats or ryegrass rotation crop. These results indicate that Brassica crops have potential for use in the control of powdery scab, Rhizoctonia disease, common scab, and other soilborne disease problems.