Revista Brasileira De Herbicidas 2015; 14(1): 54-63

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Glyphosate and cotton growth regulator sub-doses systems application

DOI: 10.7824/rbh.v14i1.276

In order to increase productivity levels, reduce costs and improve efficiency in mechanical harvesting, new technologies are being incorporated such as governor use of growth and application of sub-dose of glyphosate with promising hormetic effect on cotton plants. To do this, this study aims to evaluate the effect of the application of sub-dose of glyphosate and growth regulator system on cotton agronomic characteristics. The experimental design was randomized blocks in a factorial 6 x 2 + 1, with four replications, the first factor was frequency of application of glyphosate, using the same dose (78 g a.e. ha-1) in one single time 40 days after emergency (DAE), split in 2 times (at 40 and 50 DAE), in 3 times (40, 50 and 60 DAE), in 4 times (40, 50, 60 and 70 DAE) and 5 times (40, 50, 60, 70 and 80 DAE) , and the second factor was with and without the application of mepiquat chloride in the dose 1 L ha-1, with split spraying in 5 times, at 45, 55, 65, 75, 85 DAE, besides the control without application of products. It has been found that the use of mepiquat chloride reduced the plant height and the number of nodes of the stem. The split application of sub-dose of the herbicide in 3 times led to increased cotton yield compared to treatments without application.