Root Diseases of Cucumber in Irrigated Multiple-Cropping System with Pest Management. Donald R. Sumner, Department of Plant Pathology, University of Georgia Coastal Plain Experiment Station, Tifton 31793. Clyde C. Dowler, Agronomist (USDA-ARS), A. W. Johnson, Nematologist (USDA-ARS), Norman C. Glaze, Plant Physiologist (USDA-ARS), Sharad C. Phatak, Department of Horticulture, and R. B. Chalfant, Department of Entomology, University of Georgia Coastal Plain Experiment Station, Tifton 31793, and J. E. Epperson, Department of Agricultural Economics, Georgia Station, Experiment 30212. Plant Dis. 67:1071-1075. Accepted for publication 31 March 1983. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1983. DOI: 10.1094/PD-67-1071.

Cucumber for pickles was planted each of 6 yr in a 2-yr multiple-cropping sequence of turnip-peanut-cucumber-turnip-cucumber-soybean with four types of soil pest management. Treatments were: 1) soil fumigation with 98% methyl bromide + 2% chloropicrin (MBR-CP) each winter; 2) soil fumigation with 20% methyl isothiocyanate + 80% chlorinated C₃ hydrocarbons (DD-MENCS) each winter + maximum pest control with herbicides and a nematicide; 3) no soil fumigation, but herbicides and a nematicide used for an intermediate level of pest control; and 4) no soil fumigation or nematicide, but one herbicide and cultivation used as needed on each crop for a minimum level of weed control. Root diseases and postemergence damping-off were caused primarily by Pythium aphanidermatum, P. irregulare, and Rhizoctonia solani AG-4. The highest yields of cucumber and the lowest incidence of root disease severity and postemergence damping-off were in the MBR-CP treatment. Chloramben caused swollen, fan- to club-shaped root enlargements and apparently increased root disease severity in cucumber in the maximum and intermediate treatments. Root enlargements were no longer observed when ethalfluralin was substituted for chloramben. Turnip preceding cucumber reduced root disease severity and postemergence damping-off compared with peanut, but the difference in yield of marketable cucumbers was not significant.

Keyword(s): Meloidogyne incognita.