Atividade inseticida e mecanismos de ação de cascas de Genipa americana L. contra Tribolium castaneum (Herbst)

• Autor(a) principal: Lima, Janaína Kívia Alves
• Data de Publicação: 2020
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal de Alagoas (UFAL)
• Texto Completo: http://www.repositorio.ufal.br/handle/riufal/7281
• topic: Proteína inseticida; Plantas – Efeito dos inseticidas; Pragas – Controle; Bioquímica; insecticidal protein; pest management; biochemistry; CNPQ::CIENCIAS BIOLOGICAS::BIOQUIMICA

In order to increase knowledge about the use of botanical bioinsecticides, the search for botanical products that have mechanisms of action with less residual effects and low toxicity to other animals has increased considerably. There are no reports in the literature about the insecticidal potential of genipap (Genipa americana L.) for insects belonging to the order Coleoptera, especially for the beetle Tribolium castaneum, one of the main pests of grains and products stored in the world. In this context, the present study aimed to evaluate the effects of the extract, lectin fraction and lectin isolated from the bark of G. americana on T. castaneum. For this purpose, the aqueous extract (Tris-HCl) of the G. americana bark was prepared from which the protein fraction was obtained, derived from the saline fractionation with ammonium sulfate, and the lectin (GaBL) isolated by filtration gel chromatography. Phytochemical analysis of the extract and protein fraction of G. americana was performed. The “in vivo” bioassays were carried out using adults of T. castaneum analyzed the survival, deterrent action, the effects on the nutritional and biochemical parameters and the effects on the reproduction of insects kept over 28 days with the artificial diet methodology containing the extract, the fraction or GaBL. It can be observed that the aqueous extract of G. americana has saponins, tannins and steroids as main secondary compounds, these with insecticidal action already described for different orders of insects. It was observed that the extract of G. americana had a greater effect on the survival of T. castaneum at a concentration of 250mg / g. The extract also showed a deterrent effect and interference in the nutritional and biochemical parameters demonstrated by the reduction of food consumption and inefficiency in food conversion, causing loss of biomass. The 20% fraction also exerted an insecticidal effect on T. castaneum at concentrations of 50 and 100mg / g, but no deterrent effect was observed, however, even though the food was satisfactorily consumed, the insects were unable to convert it into biomass, and in reserves energies showing the anti-nutritional effect. GaBL is one of the active principles of the insecticidal action, demonstrated by the considerable increase in the deterrent effects and on the survival and all the nutritional and biochemical parameters analyzed in the tested concentrations. Based on the data obtained, this work represents a promising contribution to the search for alternative methods for the control of insect pests, this being the first report on the action of G. americana on T. castaneum and one of the first using a protein fraction with potential for use in pest management.