Evaluation of the toxic effect of the extracts of Palicourea marcgravii St. Hil. (Rubiaceae) on Aetalion sp. (Hemiptera: Aetalionidae) in laboratory

Abstract

In the last decades the pesticides have been used extensively in the agriculture to control plagues, contributing to the increase of the environmental impacts. Alternative forms for the control of plagues are being tested with the use of plants. The aim of the present work was to evaluate the toxic effect of extracts of Palicourea marcgravii on Aetalion sp. Two hundred adult insects were collected and separate in ten individual’s groups, put in plastic vessels and exposed to the topical application of aqueous extracts of leaves and roots of P. marcgravii. Extracts of leaves and roots were applied in the concentrations of 30, 40 and 50 mg/ml; 10, 20 and 30 mg/ml respectively. The control group was treated with distilled water. The mortality rates were evaluated of 12 in 12 hours for 48 hours. The experiments were performed in a complete randomized design with three treatments, five replicates more the control group. The extract of roots of P. marcgravii presented larger toxicity (LC50 = 12,4 mg/ml) than the extract of leaves (LC50 = 39,9 mg/ml). The extracts of P. marcgravii went toxic for adults of Aetalion sp.