VIEW ARTICLE

Responses of Beans and Peas to Root Pathogens Accumulated during Monoculture of Each Crop Species. D. W. Burke, Research Plant Pathologist, ARS, USDA, Western Region, Irrigated Agriculture Research and Extension Center, Prosser, Washington 99350; J. M. Kraft, Research Plant Pathologist, ARS, USDA, Western Region, Irrigated Agriculture Research and Extension Center, Prosser, Washington 99350. Phytopathology 64:546-549. Accepted for publication 1 November 1973. DOI: 10.1094/Phyto-64-546.

Dry beans and peas were planted two successive seasons, in fields where populations of root pathogens had previously accumulated during 15 and 6 yr of monoculture of the respective crops, and in nearby control fields of similar soil type where neither crop had been grown. Pythium ultimum, Rhizoctonia solani, and Thielaviopsis basicola infected many plants of both crop species in both previously monocultured fields; whereas Fusarium solani f. sp. phaseoli was prevalent only in the bean field, and F. solani f. sp. pisi only in the pea field. Populations of pathogens in the control fields were comparatively small. Yields of both beans and peas were high in fields previously monocultured to the other host, but were drastically reduced in their respective original fields. Activity of pathogens common to both crop species had no detectable effects on crop vigor or yields in the absence of the respective host-specific forms of F. solani.