Bioassay for Bensulide, DCPA, and Siduron in Turfgrass

Abstract

Seedlings of 22 plant species were evaluated in aqueous suspensions of N-(2-mercaptoethyl)benzenesulfonamide S-(O,O-diisopropyl phosphorodithioate) (bensulide), dimethyl 2,3,5,6-tetrachloroterephthalate (DCPA), and 1-(2-methylcyclohexyl)-3-phenylurea (siduron) to determine their value as indicator plants for bioassays. The species showing the greatest sensitivity by reductions in root or shoot lengths were evaluated in soil mixtures to determine the level of sensitivity under soil conditions. These indicator plants, in most cases, proved reliable in detecting the presence and movement of bensulide, DCPA, and siduron in soils from field-treated plots. There appeared to be no accumulation in soil treated with four annual applications of bensulide, DCPA, or siduron.