Submitted to: American Chemical Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: June 1, 2000
Publication Date: June 1, 2000
Citation: POTTER, T.L., WAUCHOPE, R.D., CULBRETH, A.K. FIELD DISSIPATION OF CHLOROTHALONIL FOLLOWING SEQUENTIAL CHEMICAL APPLICATION: A CASE STUDY OF FUNGICIDE USE IN PEANUT PRODUCTION. AMERICAN CHEMICAL SOCIETY ABSTRACTS. PP. 287-303. 2000. Technical Abstract: Peanut growers depend heavily on fungicides to control a variety of economically significant diseases. Typically 7 to 8 applications are made on a 10 to 14 day cycle until two weeks before harvest. The most commonly used active ingredient is chlorothalonil, (CAS #1897-45-6). An estimated 72 to 93% of peanut acreage is treated with up to 9 pounds per acre of the product annually (USEPA, 1999). Sequential applications during the growin season create a complex setting for active ingredient deposition on soil and foliar surfaces, its decay and metabolite accumulation and decay. An investigation conducted in Tift County Georgia during the 1999 growing season has elucidated key processes under three application scenarios. During the investigation, bulk soil samples were collected for 2.5-m experimental plots within 24 hours after each application. Samples incubated aerobically in the laboratory at 30 degrees Celsius at constant moisture content. Subsamples were analyzed for the parent compound and tw primary metabolites at 0,2,5,7,14,21,28 and 35 days after collection. In this presentation we describe identification of the metabolite, their accumulation and decay and temporal degradation dynamics using field and laboratory data.