Interação de Propaquizafop com herbicidas utilizados em arroz tolerante a inibidores de ACCase

Abstract

Weeds have the potential to cause high losses in irrigated rice (Oryza sativa), the main ones being weedy rice (Oryza sativa), barnyardgrass (Echinochloa spp.) and sedge (Cyperus spp.). Due to cases of herbicide resistance, new technologies emerged in the 22/23 harvest to control post-emergence weeds, such as rice tolerant to ACCase inhibitors. However, these herbicides only control plants from the Poaceae Family, meaning there is a need for other herbicides to control dicotyledons and sedges. However, it is necessary to understand the interaction of herbicides in tank mixtures, which may result in antagonism, synergism or additivity. For this, three studies were conducted, two in a greenhouse in Santa Maria-RS and one in the field in the municipalities of Dom Pedrito-RS and Formigueiro-RS. The first study was dose-response curves for the evaluation of herbicides in Oryza sativa, Echinochloa colona and Cyperus iria, testing doses up to 64x the recommended dose. The second was composed of isobolograms for the mentioned species, whose mixtures were arranged in different doses and proportions of herbicides, namely: 100:0, 75:25, 50:50, 25:75 and 0:100. For the third, a field experiment was carried out to evaluate the interaction between herbicide mixtures with propaquizafop and the performance of the rice crop. Mixtures of propaquizafop with bentazon, florpyrauxifen-benzyl (in the field and in a greenhouse), propanil, penoxsulan, carfentrazone, quincloraque and saflufenacil (in the field) were evaluated. The variables analyzed were weed control and dry mass, and for rice crops, phytotoxicity and yield components. Data analysis was carried out using the R software and the Colby formula, comparing the herbicides alone and in mixtures. The dose-response curves for the herbicides propaquizafop, florpyrauxifen-benzyl and bentazon were adjusted to the model, allowing the estimation of the ED50 for each herbicide for each weed species evaluated. For the isobologram, there was an adjustment for the mixture of propaquizafop with florpyrauxifen, in weedy rice the mixture was additive regardless of the proportion, as for barnyard grass, in the proportion of 25:75 (propaquizafop:florpyrauxifen) the mixture was synergistic, with 50 :50 was antagonistic and for 75:25 it was additive. For the experiment under field conditions, most interactions were additive, while the mixture of propaquizafop with propanil was antagonistic, resulting in lower control, productivity and productivity components. Mixture propaquizafop with other herbicides used in rice can be used to expand the control spectrum, taking care when mixture with propanil.