Intraguild interaction involving Spodoptera spp. and characterization of larval movement of Spodoptera eridania (Cramer) (Lepidoptera: Noctuidae) in Bt and non Bt soybean

Abstract

Spodoptera eridania Cramer, Spodoptera cosmioides Walker and Spodoptera frugiperda G.E. Smith have gotten increased importance in recent years in the soybean pest complex in Brazil. The uninterrupted crop succession (soybean, corn and cotton), the advent of Bt technology that expresses Cry1Ac protein, the presence of weeds and the low efficiency of some insecticides are some of the factors that have favored the increase of these lepidoptera pests in the field, which were previously considered secondary pests. This Brazilian scenario may also occur in the USA, since some Spodoptera species, such as S. eridania and S. frugiperda, also occur in the productive fields of that country, once it is expecting the release of Bt soybean (Cry1Ac) for the next seasons. Given this reality, it becomes important to better understand the behavioral aspects of Lepidoptera pests, as well as their movement patterns, since they share the same feeding guild in soybean plants. This knowledge can assist in soybean IPM strategies. Therefore, the objective of this work was to evaluate the intraguild interactions involving these three species under different scenarios (with and without food source) with the aid of Ethovision, as well as to characterize the larval movement of S. eridania "on-plant" and "plant-to-plant" of soybean. The possibility of carrying out these experiments in the USA will add significant value to the present research, once different conditions may contribute with the management of this pest in both countries. (AU)