LAUSR

Fungicides are routinely applied to golf course putting greens throughout the growing season. Gaining a better understanding of fungicide fate can improve fungicide use and stewardship. Therefore, optimizing fungicide applications with post-application management practices may enhance fungicide movement and limit potential off-target effects. Two field studies were initiated on a golf course putting green to evaluate the influence of post-fungicide application irrigation and mowing timing on fungicide movement into the soil profile and removal in turfgrass clippings. Plots were treated with a single application of either pyraclostrobin, triadimefon, or penthiopyrad and received 0.64 cm post-application irrigation immediately, six hours after application, or no post-application irrigation. Clippings were collected 0, 1, and 3 days after treatment (DAT) and cores were harvested 0, 1, 3, 5, 7, and 14 DAT then dissected into the remaining above ground vegetation (RAV; verdure/thatch), 0-2.5, 2.5-5.1, 5.1-7.6 cm soil subsections. A small amount of fungicide (<3.6%) was removed with clippings regardless of mowing and irrigation treatment. Post-application irrigation treatment influenced fungicide movement; however, >50% of fungicide remained restricted to the RAV for the first three DATs. Less fungicide remained restricted to the RAV and more fungicide was detected in deeper soil depths when plots were irrigated immediately after application. Fungicide was only detected in 5.1-7.6 cm depth when plots were irrigated immediately. Applying post-application irrigation immediately may result in more fungicide moving down to soilborne targets. Irrigating six hours after application facilitated moderate fungicide movement compared to irrigating immediately but was better than no post-application irrigation. Management practices affect fungicide movement and removal with turfgrass clippings. Limited fungicide (<3.6%) was removed with clippings regardless of mowing timing. Moving fungicides past the verdure/thatch is difficult regardless of post-application practice Irrigating immediately after fungicide application resulted in the most fungicide movement. This article is protected by copyright. All rights reserved.