Avaliação do efeito repelente de Nerium oleander L. e Thevetia peruviana (Pers.) K. Schum. sobre Tenebrio molitor L. 1758 (Coleoptera: Tenebrionidae)

Abstract

Granivorous insects can infest different types of stored grain, causing damage to the global economy, as well as impacts on food availability and human health. There are methods to control insect populations that use powder, extracts and essential oils from plants containing metabolites that act against herbivory with a repellent effect. In this context, the objective of this study was to evaluate the leaves repellent effect of Nerium oleander L. (oleander) and Thevetia peruviana (Pers.) K. Schum. (yellow oleander) belonging to the Apocynaceae family on the granivore beetle Tenebrio molitor L. Arenas made of plastic containers were used, where 20 adult T. molitor insects were placed in each, with 5 repetitions for each treatment. After drying the leaves, manual grinding was performed to obtain the dry powder. In the containers were added dry powder of the leaves of the two species in amounts of 0.1g, 0.5g and 1g, which were tested individually. The results showed that the repellency index of N. oleander on T. molitor was neutral in the amounts of 0.1g, 0.5g and 1.0g, while for T. peruviana it was neutral in the amounts of 0.1g, 0.5g but it was repellent in the amount of 1.0g. According to the results observed in this experiment, the powder of T. peruviana in a greater amount of treatment has a repellent effect on T. molitor. Thus, it is suggested that other parts of this plant be tested on different species of granivorous insects to control their population in stored commercial grains.