Influence of Application Method on the Activity of Butylate and EPTC in Reduced-Tillage Corn (Zea mays)

Abstract

Weed control in reduced-tillage corn (Zea maysL. ‘Pioneer 3732′) with butylate [S-ethyl bis(2-methylpropyl) carbamothioate] and EPTC (S-ethyl dipropyl carbarnothioate) was not reduced when these herbicides were applied jointly with dry or liquid fertilizer. In most cases, application with fertilizer resulted in weed control similar to that observed when the herbicide was applied in water at 285 L/ha. Butylate applied as a granular formulation also gave weed control similar to the spray at 285 L/ha. Application in 95 L/ha of water consistently resulted in reduced weed control. Corn injury was not greatly influenced by application method, and differences in corn yield appeared to be due to differences in weed control. Growth chamber bioassays indicated that both butylate and EPTC dissipated more rapidly when applied in 95 L/ha of water than the other application methods, which may explain differences in weed control observed in the field.