Avaliação da atividade repelente de extratos vegetais sobre Sitophilus oryzae em arroz beneficiado

Abstract

The objective of this study was to evaluate the repellent activity of plant extracts on Sitophilus oryzae in rice after processing, in order to aliyah them to traditional packaging that is optimized for the conservation of the product from attacks of insects. The plant extracts tested were: spinach’s alcoholic fluids, orange’s, eucalyptu’s, red pepper’s, rue’s, and garlic’s. Four trials were conducted, the first one was, just preliminary to determine the parameters of the following tests, where was tested the most appropriate doses of extracts, and two different materials to compose the active packaging later in case of comercial use. The second and third tests consisted of two bioassays attractiveness/repellency performed in arenas containing tested substance and polished rice, which also evaluated the influence of application methods of extracts in action on S. oryzae. In the fourth trial was determined the effect of extra ts on the mortality of insects after different exposure intervals of treatment. To repelency the most effective treatments were the orange extract and rue both with index 94%, followed by garlic extract with 86%. Regarding the insecticidal activity of extracts and rue orange had the highest efficiency, with a mortality rate of 95% and 84% respectively, garlic index gained 66%. Thus extracts of orange, rue and garlic showed promising results for developing packages that will assist in future conservation of rice after its processing and packaging.