Weed Control with Halosulfuron Applied Preplant Incorporated, Preemergence or Postemergence in White Bean

Abstract

Four field trials were conducted over a three-year period (2011-2013) at various locations in Ontario to evaluate the level of weed control provided by halosulfuron applied PPI,PREor POST at 17.5, 35 and 70 g &middot ai &middot ha - 1 in white bean. Halosulfuron applied PPI or PRE at 17.5, 35 and 35 g &middot ai &middot ha - 1 caused 2% or less visible injury 1 and 4 WAA in white bean. However, halosulfuron applied POST at 17.5, 35 and 70 g &middot ai &middot ha - 1 caused 2% - 8% and 1% - 3% white bean injury at 1 and 4 WAA, respectively. There was no decrease in white bean seed yield relative to the weed free check due to weed interference with halosulfuron applied PPI or PRE at doses evaluated, except when applied PRE at 17.5 g &middot ai &middot ha - 1 which resulted in a decrease in seed yield of 25%. Weed interference caused a decrease in white bean yield of 47%, 42% and 44%, when halosulfuron was applied POST at 17.5, 35 and 70 g &middot ai &middot ha - 1 , respectively. Halosulfuron applied PPI, PRE and POST controlled AMARE 92% - 100%, 8 5% - 99% and 47% - 75%; CHEAL 95% - 100%, 83% - 99% and 36% - 51%; and SIN AR 97% - 100%, 99% - 100% and 100%, respectively. Halosulfuron applied PPI and PRE reduced AMARE density 93% - 97% and 75% - 95%; CHEAL density 89% - 98% and 81% - 93%; and SINAR density 99% - 100% and 99% - 100%, respectively. Halosulfuron applied PPI and PRE reduced dry weight of AMARE 96% - 98% and 86% - 96%; CHEAL 96% - 98% and 87% - 93%; and SINAR 100% and 100%, respectively. Halosulfuron applied POST at rates evaluated reduced SINAR density and dry weight 100% but caused no significant reduction in AMARE and CHEAL density or dry weight compared to the weedy check. Based on these results, halosulfuron applied PPI orPREat 35 g &middot ai &middot ha - 1 can be used safely for the control of selected broadleaf weeds in white bean production.