Atratividade de adultos de Chrysoperla externa (Hagen, 1861) aos compostos voláteis de coentro, endro e erva-doce (Apiaceae) em condições de laboratório

Abstract

Species of Apiaceae have essential oils that may present volatile compounds that act as signals to attract and maintain natural enemies in the crop. Based on these characteristics, the objective of this study was to evaluate the attractiveness to adults of the predator Chrysoperla externa. Leaves and stems of plants of coriander, dill and fennel, collected at 30 and 60 days after sowing, were used here. The plants were arranged in four-way olfactometer (“X” format), providing odor to males and females, virgin and mated insects, in free choice tests. When released individually inside the olfactometer, five minutes were timed and the total time spent by the insect in each arm of the device was counted. Data were analyzed by the ÷² test, with expected frequencies of 25%. The yield of the essential oil of three species of plants at 30 and 60 days after sowing was evaluated by using the method of hydrodistillation. The chemical composition of the oils was determined by gas chromatography coupled with mass spectrometer. It was found that virgin adults have a preference for coriander plants, while the mated insects prefer fennel, both collected at 30 days. Plants at 60 days did not provide attractiveness response to adults of C. externa. The oil yield tended to increase with the phenological development of the plant. The chemical composition of coriander oil revealed (2E)-decenal and decanal as major components, and the highest concentration was of (E)- anethole for fennel.