VIEW ARTICLE

Disease Control and Pest Management

Soil Solarization: Effects on Verticillium Wilt of Cotton and Soilborne Populations of Verticillium dahliae, Pythium spp., Rhizoctonia solani, and Thielaviopsis basicola. G. S. Pullman, Postgraduate research plant pathologist, Department of Plant Pathology, University of California, Davis 95616; J. E. DeVay(2), R. H. Garber(3), and A. R. Weinhold(4). (2)Professor, Department of Plant Pathology, University of California, Davis 95616; (3)Research plant pathologist, AR-SEA-USDA, Cotton Research Station, Shafter, CA 93263; (4)Professor, Department of Plant Pathology, University of California, Berkeley 94720. Phytopathology 71:954-959. Accepted for publication 17 January 1981. Copyright 1981 The American Phytopathological Society. DOI: 10.1094/Phyto-71-954.

In field tests during the summers of 1977–1979, solarization of soil by covering it with transparent polyethylene tarps was examined for effectiveness in controlling soilborne pathogens. Propagules of Verticillium dahliae, Pythium spp., Thielaviopsis basicola, and Rhizoctonia solani were greatly reduced or completely eliminated 0–46 cm in soil tarped for 14–66 days. Higher soil temperatures and a more rapid decline in pathogen populations occurred in soils irrigated after placement of tarps than in those preirrigated and then tarped. Tarps 25 μm(1-mil) thick were more effective in heating soils and in killing soilborne fungi than were 100-μ (4-mil) tarps. The mycorrhizal fungus Glomus fasciculatus survived tarping treatments as measured by colonization of cotton (Gossypium hirsutum) roots. Incidence of Verticiilium wilt was reduced and cotton yields were increased in plants of cultivars Acala SJ-2 and SJ-5 planted in tarped compared with nontarped soil.