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

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 GR 25 for HOE 075032 in navy bean was &gt; 90 g/ha, while in soybean it was 16 to 24 g/ha.