Efficiency and deposition of paraquat application with adjuvant and nozzles inclination angle over Digitaria spp., Sonchus oleraceos and Amaranthus viridis

Abstract

The use of contact action herbicides with paraquat usually requires more attention with application technology aspects in relation to the systemic action ones. In order to evaluate the efficiency and deposition of paraquat application associated with adjuvant and nozzles inclination angle in weeds control, an experiment was conducted in field conditions using a factorial scheme 2 x 3 +1, with five repetitions. Seven treatments were constituted by two conditions of Gramoxone^® herbicide (paraquat, 150 g a.e. ha^-1), used with Agral^® (0.1% v/v) and Fulltec^® (0.05% v/v;) adjuvant, three nozzles inclination angle in direction of application offset (+30°; 90°; -30°) and a check without application. Natural targets were Digitaria spp., Sonchus oleraceos and Amaranthus viridis and artificial targets, plastic covers positioned over soil surface, with 10 repetitions. No significant differences were observed between application medium deposition of paraquat with adjuvant and nozzles inclination angles for A. viridis plastic covers. For Digitaria spp., paraquat deposition with Agral^® was superior to Fulltec^® using +30° and 90° angles. For S. oleraceos there was increased in paraquat deposition with Fulltec^® for -30° angle. All treatments presented efficient management (³ 91.0%) for weeds control at 3 days after application, with no significant differences regarding the studied conditions.