Drift of 2,4-D and dicamba applied to soybean at vegetative and reproductive growth stage

Deriva de 2,4-D e dicamba aplicado em estágio vegetativo e reprodutivo da soja

ABSTRACT:

The introduction of dicamba and 2,4-D-resistant soybean will increase the use of auxin herbicides for management of herbicide-resistant weeds, increasing risk of drift in non-target crops. The field experiment was conducted in 2016/17 to evaluate injury, growth, yield, germination and seeds vigor of soybean effects to simulated drift of 2,4-D and dicamba applied to soybean at the V₃ and R₂ growth stages. To simulate drift, 2,4-D was applied at 0; 5.16; 10.4; 20.8 e 41.5g ae ha^-1 and dicamba at: 0; 3.7; 7.4; 14.9 e 29.8g ae ha^-1. The injury of the dicamba is greater than 2,4-D, and the V₅ stage is more susceptible to both herbicides. The greatest reductions in soybean yield follow the drift of dicamba in R₂ and 2,4-D in V₅. The physiological quality seeds of the soybean is reduced by dicamba and 2,4-D drift at both the V₅ and R₂ stages of the soybean. Soybean is highly sensitive to low rates of 2,4-D and dicamba at the vegetative or reproductive growth stages. Dicamba causes greater negative effects than 2,4-D on soybean. The low rate of 2,4-D and dicamba reduce germination and vigor seed on soybean offspring.

Key words:
dose response; injury; germination; vigor; synthetic auxin