Adjuvant association with herbicides in burndown and post-emergency control of weeds in wheat crop

Abstract

This work aimed to evaluate associations between adjuvant to herbicides used in burndown and weeds control in post emergence conditions in wheat crop. The experiment was conducted by using randomized complete blocks with four repetitions, in factorial scheme 2 x 5 + 1, constituted by two burndown forms in pre sowing, represented by only one application and in sequence, with five adjuvant combinations (without adjuvant; Triunfo 515^®; Grap Super Gun^®; Assist^® and Fulltec^®) and a check without application. All treatments developed in burndown were submitted to the complement of post emergence control with metsulfuron-methyl or metsulfuron-methyl + 2.4-D, join to adjuvant from the respective burndown treatments. Triunfo 515^®, Grap Super Gun^® and Assist^® (70 mL ha^-1) adjuvant provided increased  in Digitaria insularis control for glyphosate Polaris^® and Atanor 480^® (2.25 L ha^-1) formulations, in unique application in pre sowing. For Commelina benghalensis, besides burndown reduction efficiency in pre sowing conditions, the use of adjuvant increased glyphosate action isolated and/or in mixture with 2.4-D and 2.4-D + metsulfuron-methyl. Associations between metsulfuron-methyl + 2.4-D, with the adjuvant, controlled satisfactory C. benghalensis in post emergency. Metsulfuron-methyl (2.4 g ha^-1) and metsulfuron-methyl + 2.4-D (2.4 + 322.4 g ha^-1), associated to the studied adjuvant did not cause harmful plant toxic action to wheat crop  BRS 220 genotype.