dose, efficacy, formulation, spray volume, sulfonylurea herbicide, type of nozzle
Abstract
The objective of this study was the evaluation of spray volume and nozzle type effect on different formulation (water dispersible granules - WG and oil dispersion - OD) of two sulfonylurea herbicides: the mixture iodosulfuron methyl sodium + amidosulfuron and iodosulfuron methyl sodium + mesosulfuron methyl efficacy. There were investigated three levels of spray volume (125 l*ha-1, 250 l*ha-1 and 350 l*ha-1) and two types of nozzle (extended range flat nozzle TeeJet XR 11003-VS and drift guard flat nozzle TeeJet DG 11003-VS). Each herbicide was used at recommended dose and reduced by half. Spray volume and nozzle type did not affect activity of the mixture iodosulfuron methyl sodium + amidosulfuron, but differentiated the efficacy of OD formulation of iodosulfuron methyl sodium + mesosulfuron methyl, when it was applied at lowered dose. As spray volume rose, herbicide efficacy decreased. Nozzle type influenced OD formulation of the mixture iodosulfuron methyl sodium + mesosulfuron methyl, independently on dose. Significantly weaker efficacy was obtained when drift guard nozzle was used.
