Insecticidal activity of plant extracts against whitefly nymphs Bemisia tabaci (Hemiptera: Aleyrodidae) in laboratory

Abstract

21 plant extracts were evaluated against nymphs Bemisia tabaci under laboratory conditions. For the establishment of the test, the nymphs (N2) immersion technique was used, using a completely randomized design with 8 concentrations and 10 repetitions evaluating after 72 hours. For the estimation the susceptibility (LC50 and LC95) the Probit Analysis was used, the main phytochemical compounds in the extracts were determined using the infrared spectrophotometer. The results show a high susceptibility to cat's claw (Mimosa zygophylla), dragon's blood (Jatropha dioica), garlic (Allium sativum), ribwort (Plantago lanceolata) and lechuguilla (Agave lechuguilla), with a LC50 of 778, 795, 890, 996 and 1035 ppm respectively. The compounds present in the evaluated extracts were different types of acids (benzoic, linoleic, palmitic, shikimic, cinnamic, coumaric and tartaric), 1, 8-cineole and eugenol, possibly responsible for the insecticidal activity.