Economic injury levels for control decision-making of thrips in soybean crops (Glycine max (L.) Merrill)

Abstract

Soybean, Glycine max (L.) Merrill, is the most cultivated crop worldwide. Recently, thrips (Thysanoptera: Thripidae) has caused of up to 17% production losses to this crop. To improve its management, economic injury levels (EIL) are key tools in supporting decision-making systems in integrated pest management (IPM) programs. The EIL depend on the technology used for insecticide application. In this regard, pesticide treatment on soybean crops can be successfully performed by aircraft or tractors, especially among major producers (e.g., Brazil, the United States, Argentina, and China). There are currently no economic injury levels (EIL) for thrips in soybean crops. Therefore, the objective of this work was to determine economic injury levels for thrips in soybean, with insecticide applications by aircraft and by tractors. The study was carried out in four commercial soybean crops for two years. Frankliniella schultzei and Caliothrips phaseoli were observed attacking soybean plants. The EIL were 4.53 and 3.43 thrips sample-1 for insecticide application with aircraft and tractor, respectively. The economic injury levels, established in this study, can be used in integrated pest management program for soybean crops.