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POSTERS: Chemical control

Where does your fungicide go? Fungicide fate following various mowing and irrigation treatments
Cameron Stephens - North Carolina State University. James Kerns- North Carolina State University, Travis Gannon- North Carolina State University

Irrigation is typically applied immediately following fungicide applications when targeting root diseases in golf course putting greens. However, the fate of fungicides following post-application mowing and irrigation is not well documented. The objective of this study was to determine the influence of post-application mowing and irrigation timing on fungicide amounts in turfgrass clippings and the soil profile. Single fungicide applications of pyraclostrobin, triadimefon, and penthiopyrad were applied and 0.64 cm of post-application irrigation was applied either immediately or 6 hours following fungicide application. Turfgrass clippings were collected at 0, 1, or 3 days after treatment (DAT). Soil cores were collected 0, 1, 3, 7, and 14 DAT and dissected into remaining above ground vegetation (RAV), 0-2.54cm, 2.54-5.08cm, and 5.08-7.62cm depths. All samples were homogenized and fungicide residue was analyzed using liquid chromatography mass spectrophotometry. Fungicide recovery as percent of applied ranged from 90-93%, 92-99%, and 92-95% at 0 DAT for pyraclostrobin, triadimefon, and penthiopyrad, respectively. Only a minor amount of fungicide (0.19-2.31%) was removed with turfgrass clippings regardless of mowing and irrigation treatment. Fungicide was detected in the 5.08 to 7.62-cm depth at 14 DAT only when irrigated immediately. Less penthiopyrad was detected in the RAV and total fungicide recovery was greater through 5 DAT compared to pyraclostrobin and triadimefon. More penthiopyrad was detected in the 0-2.54cm depth at 1 DAT compared to pyraclostrobin and triadimefon.