SELETIVIDADE INICIAL DE MESOTRIONE EM DIFERENTES MODALIDADES DE APLICAÇÃO PARA A CULTURA DO MILHO DOCE

Abstract

Sweet corn is classified as a vegetable crop due to the high value it adds, to intensive cultivation and exclusive destination to human consumption, it is a vegetable for industry processing. Brazil has a high potential for sweet corn production and unlike common corn there is still a lack of technical information related to your cultivation. The interference of weeds is a factor of great importance to the cultivation of sweet corn, which can cause damages in yield and quality. The sweet corn may present varying levels of tolerance to mesotrione treatment, resulting from the application of increasing dosages and different growth stages of the crop. Due to the lack of information concerning herbicide selectivity in sweet corn, the aim of this work was at evaluate the selectivity of the herbicide mesotrione to sweet corn, by dose-response curves, sprayed in different application modalities. The experiment was conducted in a greenhouse in the experimental area of Instituto Federal Goiano (IF Goiano), Campus Morrinhos - GO. The experimental design was a randomized complete blocks, in factorial scheme 5x3, with five replications. The factors were constituted by five dosages of mesotrione (0, 72, 144 – recommended dosage, 288 and 576 g ha-1) and three periods of application of the herbicide (pre-emergence - post-sowing, post-emergence - V3 and post-emergence - V6), with 15 treatments in total. The evaluations of intoxication, chorophyll (SPAD index), growth and biomass of the aerial part of the plants were carried out in order to study the effects of mesotrione on the crop. No relevant interaction was detected in the study (p<0,05) between the assessed factors (periods of application and herbicides dosages). On average, there was a relevant effect to the periods of application depending on the response variable. Mesotrione is selective to Tropical Plus hybrid sweet corn up to four times the recommended dosage of the herbicide (4 x 144 g ha-1) or (576 g ha-1) both in pre-emergence and post-emergence applications (V3 and V6 growth stages).