Bioactivity of plant extracts from caatinga on cowpea weevil, Callosobruchus maculatus (Coleoptera: Chrysomelidae: Bruchinae)

Abstract

Cowpea (Vigna unguiculata) is an economically and nutritionally important crop. However, cowpeas are subject to attack by insect pests that reduce the quality and nutritional value of the grains during storage. The use of plant-based products as an alternative control of insect pests has been highlighted for their low toxicity on the environment and human health. This study aimed to evaluate the bioactivity of different plant extracts on the cowpea weevil (Callosobruchus maculatus). A completely randomized design was adopted with seven treatments and six replicates. The treatments consisted of extracts from six plants, namely Morus nigra, Anadenanthera macrocarpa, Dysphania ambrosioides, Moringa oleifera, Ziziphus joazeiro, and Licania rigida and saline solution (NaCl) 0.15 M as control. Survival probability, oviposition, and adult emergence were evaluated. The plant extracts showed different effects on C. maculatus, with D. ambrosioides extract being the most lethal to the bean weevil. A. macrocarpa and D. ambrosioides extracts showed repellency against the cowpea weevil; A. macrocarpa, D. ambroisoides, Z. joazeiro, and L. rigida extracts interfered with the oviposition of females; and M. oleifera and Z. joazeiro extracts decreased the emergence of male and female C. maculatus.