The selectivity of post-emergence applied herbicides in the corn crop (Zea mays L.) when mixed in tank with insecticides used to control Spodoptera frugiperda (J.E. Smith) was verified. The experiment was carried out in off-season maize, seeded in February 2004, using the hybrid AGN 2012, in conventional system. The experimental design was randomized blocks with split-plots scheme, on double check model, four replicates and 15 treatments. The treatments were constituted by the combination of three levels of the factor herbicide (g ha-1): mesotrione (120) + atrazine (1500) + Assist 0,5%, nicosulfuron (20) + atrazine (1500) and hand-weeded checks; with five levels of the factor insecticide: lambdacyhalothrin (10), chlorpyrifos CE (240), chlorpyrifos EC (225), lambdacyhalothrin + thiamethoxam (12,5 + 5,5) and checks without insecticide application. Moderate phytotoxic symptoms were observed to mesotrione treatments and severe symptoms were observed to nicosulfuron caused by the interaction of these herbicides with the insecticide chlorpyrifos (formulations CE and EC). No yield losses were recorded as due to phytotoxicity.
interaction; phytotoxicity; yield; Zea mays
