Algodoeiro voluntário : efeito de cultivares e da presença do línter no controle com herbicidas registrados para a cultura da soja

Abstract

The objective of this study was to evaluate alternatives for the control of cotton cultivars with herbicides registered for soybean crop in pre and post-emergence modalities. Five experiments were carried out in a greenhouse with plots consisting of pots filled with clayey soil (46% clay), commercial cotton seeds were sown at 1 cm depth simulating volunteer cotton plants. Cultivar, herbicide and interaction of the two factors were evaluated. The first experiment with pre-emergence herbicide application shows the control results influenced by the herbicide and cultivar interaction, which acted depending on each other. The second experiment, in pre-emergence, presented only different levels of control depending on the herbicide. For both experiments, the herbicide metribuzin was the one that best controlled volunteer cotton, and about the cultivars, the most tolerant to herbicides was TMG 62 RF. Experiments 3 and 4 compared pre-emergence herbicide control in volunteer cotton from treated commercial seeds and linted seeds coming directly from the field. The results show that only the cultivar FM 985 GLTP responded differently to the herbicide sulfentrazone when lint was present. In experiment 5, the cultivars were submitted to fomesafen in post-emergence (62.5 and 250 g ha-1) at V1 stage of cotton. The cultivar TMG 62RF responded differently to the other cultivars for the dosage of 62.5 g ha-1. The dosage of 250 g ha-1 of the herbicide controlled all cultivars.