ALTERNATIVES FOR THE CONTROL OF VOLUNTARY SOYBEAN RR® IN COTTON CROP

With the advent of cotton cultivation in the second harvest, the control of volunteer soybean GR (R) has become an indispensable operation on cotton. So, this study had to evaluate the efficiency of different alternatives to chemical control of volunteer plants RR (R) soybean, through an assessment of herbicides used in cotton. Two experiments were established in greenhouse, one with soybean plants in stage V1 and the other in V2. There were evaluated 21 treatments, compounds by alone and in mixture of herbicides pyrithiobac-sodium, amonio-glufosinate, glyphosate and trifloxysulfuron-sodium at different rates. The variables analyzed were: control at 7 and 28 days after herbicide application (DAA), dry weight and plant height at 28 DAA. The results showed that none of the mixtures showed antagonism between the herbicides in control of GR (R) soybeans. Different levels of suppression can be obtained by application of the herbicides evaluated, but, only the amonio-glufosinate, isolated and associated with pyrithiobac-sodium controlled all volunteer plants, regardless of the application stage. In general, soybean was more tolerant to herbicides while in more advanced growth stage.