Reduction of spinosad rate for controlling Liriomyza huidobrensis (Diptera: Agromyzidae) in dry beans (Phaseolus vulgaris L.) and its impact on Frankliniella schultzei (Thysanoptera: Thripidae) and Diabrotica speciosa (Coleoptera: Chrysomelidae)

Abstract

Spinosad at 163.20 g a..i./ha is recommend to control Liriomyza huidobrensis (Branchard) on potato in Brazil. The use of adjuvant might help to reduce the required rate to achieve acceptable control of this pest. Therefore, spinosad, recommended at 163.20 g a.i., was tested at 79, 84 and 96 g a.i./ha in field conditions on controlling Liriomyza huidobrensis (Branchard) on dry beans, aiming to evaluate rate reductions with the mixing of the adjuvant polyether-polymethylsiloxane-copolymer (Break Thru®). The impact of this strategy was also evaluated on Frankliniella schultzei (Trybom) and Diabrotica speciosa (Germar). A significant increase in spinosad performance was observed when tank mixed with Break Thru® 0.05% v/v, with reduction of infestation of L. huidobrensis up to 50% when compared to the same rate without mixing the adjuvant. No statistical difference on spinosad rates (72, 84 and 96 g ai/ha + Break Thru® 0.05% v/v) was observed. All spinosad + Break Thru® treatments showed acceptable performance on the dry bean pests evaluated, by reducing pest population with efficacy about 80%. The control of L. huidobrensis was slightly superior with abamectin in some trials; however, spinosad + Break Thru® outperformed the other treatments for controlling thrips, with reduction of pest population up to 75%. In conclusion, all spinosad tested rates + Break Thru® can be successfully applied on dry bean crops to control these pests.