Impact of adjuvants on bentazon efficacy on selected broadleaf weeds

摘要

Tank-mix adjuvants can increase the efficacy of herbicides. Therefore, the effects of different rates of bentazon alone or tank-mixed with ammonium sulfate, non-ionic (0.25% Induce) or organosilicone (0.1% Kinetic) adjuvants were investigated on cocklebur (Xanthium strumarium), black nightshade (Solanium nigrum), velvetleaf (Abutilon theophrasti), and stranglervine (Morrenia odorata) under greenhouse condition. There were variations in susceptibility of the four weed species to bentazon-adjuvants tank-mixture treatments. Black nightshade control never exceeded 55% with all bentazan treatments rates from 0.84 to 2.24kg ha^-^1 with or without the adjuvants. While cocklebur was completely controlled with the application of bentazon at 1.12kg ha^-^1, or with bentazon at 0.84kg ha^-^1 plus one of the three adjuvants, with insignificant differences between adjuvants. The limited factor of controlling velvetleaf and stranglervine is the bentazon rate. Complete foliar death (98-100%) of velvetleaf and stranglervine was with bentazon at 1.68kg ha^-^1 alone or with Induce or Kinetic adjuvant. The results suggested that black nightshade was difficult-to-control weed, while cocklebur was susceptibility to bentazon at lowest rate (0.84kg ha^-^1) plus adjuvant. Mixing adjuvant with bentazon generally enhanced common cocklebur and black nightshade control, while addition of adjuvant to bentazon at all rates for controlling stranglervine did not cause any significant difference.