Potential Movement of Dithiopyr following Application to Golf Courses

Abstract

AbstractResearch was conducted to evaluate the potential movement of dithiopyr [S,S‐dimethyl2‐(difluoromethyl)‐4‐(2‐methylpropyl)‐6‐(trifluoromethyl)‐3,5‐pyridinedicarbothioate] from golf courses. Dithiopyr was applied as granule and emulsifiable concentrate (EC) formulations to ‘Penncross’ creeping bentgrass (Agrostis stolonifera L.) and ‘Tifdwarf’ hybrid bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt‐Davy] in simulated greens. Less than 0.6% of the dithiopyr was transported through the rooting media (a mixture containing at least 97% coarse sand by weight with sphagnum peat moss). Dithiopyr concentrations in the leachate, transported through the greens, did not exceed 3 µg L−1. Most of the dithiopyr (11–31%) was detected in the top 0 to 12.5 cm of rooting media at the end of the greenhouse experiments and as much as 20% of the applied dithiopyr was removed with the leaf clippings over the duration of the greenhouse experiments. The highest concentration of dithiopyr transported in the runoff water from simulated golf course fairways did not exceed 40 µg L−1. Generally, the concentration of dithiopyr in the runoff water was higher when applied as an EC formulation compared with the granule formulation at 1 d after treatment (DAT). The dithiopyr concentration, in the runoff water, had decreased to near 9 µg L−1 at the 8 DAT sampling period and less than 2.0% of the applied dithiopyr was transported from the simulated fairways.