VIEW ARTICLE

Disease Control and Pest Management

Effect of Dibromochloropropane Fumigation on the Growth of Sclerotium rolfsii and on the Incidence of Southern Blight in Field-Grown Peanuts. R. Rodríguez -Kábana, Professor, Department of Botany and Microbiology, Auburn University, Auburn, AL 36830; M. K. Beute(2), and P. A. Backman(3). (2)Professor, Department of Plant Pathology, North Carolina State University, Raleigh, NC 27650; (3)Associate professor, Department of Botany and Microbiology, Auburn University, Auburn, AL 36830. Phytopathology 69:1219-1222. Accepted for publication 25 May 1979. Copyright 1979 The American Phytopathological Society. DOI: 10.1094/Phyto-69-1219.

The fumigant nematicide 1,2-dibromo-3-chloropropane (DBCP) was applied to soil infested with Sclerotium rolfsii contained in standard petri dishes. DBCP at concentrations less than 9.6 mg/dish (11.5 L/ha) resulted in stimulation of mycelial growth and production of sclerotial initials by S. rolfsii as measured 4 days after application; higher concentrations of DBCP resulted in either no change or less mycelial growth, and in fewer initials than those for the control. Counts of mature sclerotia at the 10th day were in indirect proportion to DBCP concentration and the number of colonies of Trichoderma spp. found on colonies of S. rolfsii increased. When sclerotia produced on nonsterile soil were exposed to vapor from 1 ml of emulsions containing 0–8% (v/v) DBCP in 24-cm-diameter desiccators with moist BaO₂ (O₂ supply), sclerotial germination was significantly stimulated by the vapor from emulsions containing 1–4% DBCP. Natural sclerotia on soil amended with decomposed peanut crop residue produced significantly more new sclerotia when exposed to DBCP vapor from 1 ml of a 1% (v/v) emulsion in the desiccators than those in desiccators without DBCP. Incidence of disease caused by S. rolfsii generally increased in Florunner peanut fields treated with DBCP over a 5-yr period.