Patrícia Aparecida de Carvalho Felisberto
Abstract:
In aerial application of sugarcane ripeners, the spray should reach its target without drift, avoiding contamination of surrounding crops. The objective was to evaluate the effect of sugarcane ripening underdoses on corn crop when applied in development stages V4 and V8. Three trials were installed at the Federal University of Goiás Farm, UFG, Jataí Regional. Each plot contained 10 lines of the SYN 7G17 corn hybrid. Each trial consisted of eight treatments established in a randomized block design in a 2 x 4 factorial scheme plus a control treatment (without maturation), with four replications. The first factor corresponds to the application in the V4 and V8 stages of maize crop and the second factor to the subdoses of 3; 6; 9 and 12% of ethephon 475.2 g ai ha-1 (Test I), 216.0 g glyphosate ea ha-1 (Test II) and 15.0 g ai ha-1 methyl sulfometuron (Test III) . At 20 and 36 days after sowing, when the corn plants were in V4 and V8, respectively, the ripeners were applied. Phytotoxicity effects were noticeable at both stages at 7, 14, 21, 28 and 42 days after application only for Test III. For glyphosate, ear length and diameter were affected for both stages. Corn crop is sensitive to underdoses from 0.45 g i.a.ha-1 of methyl sulfometuron at developmental stages V4 and V8. Grain yield was lower only for plants submitted to methyl sulfometuron subdoses, with less effect when drift occurs at development stage V8 compared to stage V4.
