Bentazon Tank-Mixtures for Improved Redroot Pigweed (Amaranthus retroflexus) and Common Lambsquarters (Chenopodium album) Control in Navy Bean (Phaseolus vulgaris)

Abstract

Field studies were conducted from 1991 to 1994 to investigate the effectiveness of reduced rates of bentazon in tank-mixtures with imazethapyr, thifensulfuron, or HOE 075032 for improved control of redroot pigweed and common lambsquarters in navy bean. Tank-mixtures of bentazon at 600 g ai/ha plus imazethapyr at 25 g/ha or HOE 075032 at 5 to 15 g/ha controlled both redroot pigweed and common lambsquarters. These rates represent an approximate 45% reduction in total amount of active ingredient needed to control these weeds compared with full label rates. Bentazon tank-mixtures with 2 or 4 g/ha of thifensulfuron controlled these weeds but caused severe injury and delayed crop maturity. In greenhouse studies, the GR₂₅for HOE 075032 in navy bean was > 90 g/ha, while in soybean it was 16 to 24 g/ha.