Eficácia do Herbicida Haloxyfop R (GR-142) Isolado e Associado ao 2,4-D no Controle de Híbridos de Milho RR® Voluntário

The volunteer corn Roundup Ready ® has been effective managed by ACCase graminicides as burndown prior to sowing soybean. However, before crop installation, there are other glyphosate-tolerant weeds in the field such as Conyza sp. , Commelina sp., Ipomoea sp., Spermacoce latifolia and Richardia brasiliensis . Thus, the tank mixture of ACCase inhibitor herbicides with 2.4-D, is increasing in this segment. The present study evaluated the efficacy of Haloxyfop (GF-142) isolated and with 2.4-D (DMA 806 BR ® ) to volunteer corn control sprayed at different stages. One trial was conducted in field conditions with the corn RR ® hybrids as DKB240PRO 2, AG8025RR2, Pioneer30F53HR and AG9045RR2 using a randomized block design in a split-plot factorial 8x2+1 with four replications. The main factor was the rate of haloxyfop GF-142 (25, 50 and 62 g a.i. ha -1 ) and clethodim (84 g a.i. ha -1 ) with or without the herbicide 2.4-D (670 g a.e. ha -1 ). The second factor was the application on volunteer corn stage at V 5 and V 7 . The herbicide GR-142 at 25, 50 and 62 g a.i. ha -1 , alone or with 2.4-D, was effective to control the volunteer corn plant hybrids DKB 240 PRO2, RR2 AG 8025, AG 9045 and RR2 Pioneer 30F53HR at both V 5 and V 7 stages. The same result was observed with the standard clethodim, alone and mixed with 2.4-D. However, the control at the V 7 stage was slight slower than at the V 5 stage.