CORE CULTIVATION AND EFFICACY OF BENOMYL APPLIED TO CREEPING BENTGRASS

Hollow tine core cultivation is practiced for the management of creepi ng bentgrass [Agrostis stolonifera L, var. palustris (Huds,) Farw.; sy n, A. palustris Huds.] golf course greens and fairways to increase wat er infiltration, increase turf root and shoot growth, and control that ch. Benomyl [methyl 1-(butylcarbamoyl)-2-benzimidazole carbamate] is c ommonly used on turf as a soil drench for the control of disease such as dollar spot (caused by Sclerotinia homoeocarpa F.T. Bennett), Our o bjective was to determine the effect of core cultivation on the moveme nt of a systemic pesticide in thatch and soil and the uptake by turfgr ass using benomyl as a model. Core cultivation was conducted 1, 7, and 14 d before benomyl application in a field trial during 1992 and 1993 to study the effect of coring and time of coring on the movement and uptake of benomyl and control of dollar spot disease. Fungicide levels in turfgrass clippings, thatch and soil were determined by bioassay, Core cultivation I d before benomyl treatment provided the longest las ting uptake of benomyl and control of dollar spot disease compared wit h 7 and 14 d before benomyl treatment. Clipping, thatch, and soil samp les from areas close to the coring holes had significantly higher (P = 0.05) levels of fungicide residues than those farther from the coring holes. This study suggests that core cultivation shortly before benom yl application can increase movement of benomyl into thatch and soil, thereby increasing uptake of benomyl by turfgrass and improving diseas e control.