Óleo essencial de Croton tricolor: avaliação de repelência e toxicidade contra o Tribolium castaneum

Abstract

Studies carried out with plant essential oils have demonstrated their potential as natural insecticides that can act to control stored product pests, such as Tribolium castaneum, thus being an interesting alternative to conventional insecticides that can cause a series of health damages. of humans and the environment. In this regard, the essential oils of plants of the genus Croton show promise in the control of insect pests, with the essential oil of the species Croton tricolor recognized as a natural extract that is nontoxic for mammals. Therefore, this study sought to evaluate the potential toxicity and repellency of essential oils from the branches and leaves of C. tricolor, a species of aromatic plant collected in the interior of the state of Alagoas, against T. castaneum. In addition to estimating the LD50, and evaluating the chemical composition of these oils and their effects on the metabolic profile of insects. The assessment of the potential for toxicity was carried out through the contact biotoxicity test, and the potential analysis of the repellency of essential oils against the insect was carried out based on the method by Baccari and collaborators (2020), obtaining, in the end, promising and positive results. in relation to both tests, despite the mechanism of action not being clearly elucidated, it is possible to estimate the LD50 in solutions with a concentration of approximately 5% of the essential oil, and repellency percentage between 70% and 100%, class IV and V, according to McDonald et al. (1970). The analysis of the chemical composition of the oils was performed by gas chromatography coupled to mass spectrometry and variations of terpenes were identified as major compounds. However, inconclusive results were observed regarding changes caused by essential oils in the metabolic profile of insects.