The interaction of pyroxasulfone and flumioxazin applied pre-emergence for the control of multiple-herbicide-resistant waterhemp in soybean

Abstract Six field experiments were conducted to investigate any interaction between pyroxasulfone and flumioxazin on soybean tolerance control of multiple-herbicide-resistant (MHR) waterhemp in during 2016 2017 Ontario, Canada. There was a synergistic increase injury with the co-application at all rates evaluated 2 wk after emergence (WAE), two highest (134/106 268/211 g ai ha –1 ) 4 WAE, rate (268/211 8 WAE. Soybean treatments transient had no adverse effect grain yield. Pyroxasulfone applied preemergence 45, 89, 134, 268 controlled MHR up 72%, 89%, 92%, 95%, respectively. Flumioxazin 35, 70, 106, 211 78%, 90%, 93%, 96%, Pyroxasulfone/flumioxazin 45/35, 89/70, 134/106, 98%, 100%, significant antagonistic or interactions for pyroxasulfone/flumioxazin except , which provided The biomass density reductions followed trend similar visible control. caused response reduction (9% difference). Based these results, there is an additive potential plus flumioxazin.