Bioatividade de extratos vegetais sobre o caruncho do feijao caupi Callosobruchus maculatus (Fabr., 1775) (Coleoptera: Chrysomelidae).

Abstract

Cowpea (Vigna unguiculata) is a traditional source of feed and also income for small rural producers, mainly in Northeast Brazil. However, Cowpea’s cultivation is subjected to postharvest losses due to the attack by pests at storage, consequenly decreasing the grain’s quality and it’s nutritional value. The storage pests control can be done by usuing insecticides of botanical origin, a viable alternative, with low environmental impacts and easy application, since the products can be used in different forms such as oils, powders or plant extracts. Therefore, this work objetve was to evaluate the bioactivity from several plant extracts on cowpea woodworm (Callosobruchus maculatus). The study was conducted at the Chemicals Selectivity Laboratory (LSPQ) of the Federal Rural University of the SemiArid, Campus Mossoró, RN. The experiment was carried out in a completely randomized design with 7 treatments and 6 repetitions. The treatments consisted of: T1 = 0.15 M saline (NaCl) (control); T2 = angico extract; T3 = blackberry extract; T4 = mast extract; T5 = moringa extract; T6 = extract of juazeiro; T7 = octica extract. The extracts were obtained from the leaves through a 10% (w/v) extraction process in 0.15 M NaCl solution, under constant agitation as well as a subsequent centrifugation to collect the crude extract. The effect of these extracts on the survival and behavior of C. maculatus on cowpea beans was tested in three trials: repellency activity, survival rate and biological changes. The plant extracts had different effects on C. maculatus, with emphasis on the mastruz extract, which was the most lethal for both, bean weevil and angico extract, since they have shown repelling action. The extract of octaica presented interference at the oviposition of the females, while the extracts of moringa and juazeiro interfered on a negative way at the emergence of males and females of C. maculatus.