Prohexadione-calcium isolated or in association with herbicides and other products in the handling of cotton pre-harvest

Abstract

To maintain the quality of the cotton fiber, as well as to provide great yields on the harvest, some aspects must be taken into account such as the uniformity of the bolls and the defoliation; therefore, the use of herbicides and maturators become indispensable. Thus, the objective of this paper was to evaluate the efficiency of the prohexadione-calcium regarding its isolate application and in association with other products in the uniformity and opening of the cotton bolls, as well as the defoliation effect and regrowth of the crop. For such, a field experiment was carried out in the municipality of Diamantino - MT. The outline adopted was of randomized blocks with four repetitions and thirteen treatments, those being composed of control without application; prohexadione-calcium + ethephon + cyclanilide; prohexadione-calcium + flumiclorac-pentyl; prohexadione-calcium + diuron + thidiazuron; prohexadione-calcium + pyraflufen-ethyl; prohexadione-calcium; prohexadione-calcium + iharol. The treatments were applied when approximately 85% of the bolls of the crop 975 WS were open. The variables: apple opening, regrowth and defoliation were analyzed at 0, 3, 6, 10 and 15 days after the application (DAA) and, finally, the productivity of seed cotton was determined. Regardless of the dose, the plants that received prohexadione-calcium associated with ethephon + cyclanilide, diuron + thidiazuron and pyraflufen-ethyl presented a greater number of open bolls and greater defoliation. We can conclude that the different chemical treatments did not provide statistical differences regarding the regrowth of cotton before the harvest, at 15 DAA, and that the use of prohexadione-calcium, isolated or in association with other products, regardless of the dose, did not influence in the productivity of the seed cotton.