VIEW ARTICLE

Disease Control and Pest Management

The Influence of Several Crop Sequences on the Incidence of Verticillium Wilt of Cotton and on the Population of Verticillium dahliae in Field Soil. E. J. Butterfield, Department of Plant Pathology, University of California, Davis, CA 95616, Present address of senior author: Boyce Thompson Institute for Plant Research, Inc., Yonkers, NY 10701; J. E. DeVay(2), and R. H. Garber(3). (2)Department of Plant Pathology, University of California, Davis, CA 95616; (3)USDA-ARS, U.S. Cotton Research Station, Shafter, CA 93263. Phytopathology 68:1217-1220. Accepted for publication 27 February 1978. Copyright © 1978 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-68-1217.

Since Verticillium dahliae was not detectable by soil assay or by subsequent infection of cotton plants, it was considered to be eradicated from most field test plots following a 1-yr rotation between cotton and paddy rice (continuous flooding.) In contrast, populations of V. dahliae per gram of soil were increased with rotations to safflower or with continuous cotton. Keeping soil wet but not flooded for 6 wk and/or rotations with grain sorghum or dry fallow did not change the concentration of V. dahliae propagules in soil. Significant (P = 0.05) decreases in disease incidence and increases in cotton lint yields resulted from rotations with paddy rice, perennial ryegrass, and in some fields from safflower, grain sorghum, or frequent soil irrigation followed by grain sorghum.