Sub-doses of 2-chloroethylphosphonic acid in vegetative stages of corn cultivation 1 Subdoses do ácido 2-cloroetilfosfônico em estádios vegetativos da cultura do milho

The use of ripeners has been common practice in sugarcane cultivation. The application of these products is often performed through aerial spraying, which increases the chances of molecules from the ripener drifting into other crops, such as corn. With the aim of studying possible phytointoxication in corn caused by ethephon drift, a field experiment was conducted in order to evaluate the effect of ripener sub-dosing when applied in the V4 and V8 development stages of corn cultivation. The experiment was set up in a randomized block design, with four replications. Treatments were arranged in a 2 x 5 factorial scheme, with first factor corresponding to the corn growth stages in which the ripener was applied (V4 and V8), and the second factor referred to the ethephon sub-doses (0; 14.26; 28.51; 42.77, and 57.02 g ha a.i.). Visual phytotoxicity effects were not perceptible when sub-doses were applied in the V4 and V8 corn growth stages. Similarly, agronomic characteristics and grain yield were not altered by ethephon sub-doses of up to 57.02 g ha a.i.