Botanical compounds as an alternative to control Striacosta albicosta and its sublethal effects on the ladybug Hippodamia convergens

Botanical insecticides can be an alternative to control western bean cutworm Striacosta albicosta (Smith; Lepidoptera: Noctuidae), a critical pest of corn and dry beans. However, the compatibility of these compounds with natural enemies must be evaluated. We evaluated the lethal effect of botanical compounds on S. albicosta and Hippodamia convergens Guerin-Meneville (Coleoptera: Coccinellidae), as well as the selectivity and sublethal effects of these compounds on the behavior and larval development of H. convergens. The ethanolic extracts of Annona mucosa (Jacq.), Annona muricata L., and Annona sylvatica A.St.-Hil; the botanical insecticides Azamax®, Anosom®, and Matrine®; and the positive controls of synthetic insecticide active ingredients bifenthrin and chlorantraniliprole, were tested. Among the botanical insecticides, Matrine® was the most toxic treatment for S. albicosta. All the botanical compounds tested were more toxic to H. convergens compared to S. albicosta, except for Matrine®. Bifenthrin and Anosom® reduced the distance traveled by first instar larvae of H. convergens. Insect speed was reduced by bifenthrin, Anosom®, Azamax®, and the extracts of A. mucosa and A. muricata. The larval development time of H. convergens in the control treatment did not differ from Matrine® and bifenthrin. Larval survival was similar between the control and Matrine®. The treatments Azamax®, Anosom®, and A. sylvatica caused 100% larval mortality. These results indicate the incompatibility of some botanical compounds with H. convergens. However, the study reveals the potential of the botanical insecticide Matrine® in controlling S. albicosta and its selectivity to H. convergens.