Toxicidade residual de extratos aquosos de Nim sobre a abelha africanizada Apis Mellifera.

Abstract

Apis mellifera bees (Hymenoptera: Apidae) are considered the world's leading pollinating agents. However, the disordered use of insecticides has contributed to the decline of these insects. In this sense, the number of studies with Azadirachta indica, an important plant species being used for the synthesis of biopesticides, has been growing. Therefore, the present study aimed to evaluate the residual toxicity of the aqueous extract of leaves and seeds of nim A. indica on the africanized bee A. mellifera. The experiment was carried out in the Entomology Laboratory of the Academic Unit of Agrarian Sciences (UAGRA), belonging to CCTA/UFCG, Pombal-PB. The bioassay was carried out in a completely randomized design composed of eight treatments: Absolute control - distilled water; Positive control - Actara® (Tiamethoxam) (600g/ha), denim leaf extract dose 1 (5 g/100mL), dose 2 (10 g/100mL) and dose 3 (20 g/100mL), extract de nim seeds dose 1 (5 g/mL), dose 2 (10 g/100mL) and dose 3 (20g/100mL), containing 10 replicates, each experimental unit consisting of 10 adult worker bees of A. mellifera. After the application of the treatments, mortality and adverse effects on bee behavior (prostration, tremors, paralysis, feed reduction) were evaluated at 1, 2, 3, 4, 5, 6 and 24 hours after the beginning of exposure. The highest mortality was observed for the mean and maximum doses of seed extract, which caused 14% death. Leaf extracts caused low mortality levels for all doses, being statistically equal and little toxic on adult bees. Regardless of the concentration evaluated, the aqueous extracts of leaves and denim seeds were little toxic to A. mellifera under the residual exposure mode. Both did not influence the mortality and behavior of the bees, as well as did not affect the flight capacity.