Toxicidade de inseticidas derivados do Nim, via pulverização direta, sobre Apis Mellifera (Hymenoptera: Apidae).

Abstract

In the last decades, the disappearance of bees in agricultural areas has been observed, with the excessive use of phytosanitary products being the main factor pointed to this decline, making it necessary to carry out studies on the toxicity of insecticides on pollinators. Therefore, the aim of this study was to evaluate the toxicity of aqueous extracts of neem used to control pests on the Apis mellifera, via direct spraying of the products on bees. The study was carried out at the Entomology Laboratory of the Centro de Ciências e Tecnologia Agroalimentar (CCTA) of the Universidade Federal de Campina Grande (UFCG), Pombal – PB. To carry out the experiments, were used adult workers of A. mellifera from colonies belonging to the CCTA/UFCG apiary. The treatments evaluated were: absolute control (distilled water), positive control (thiamethoxam insecticide - 600g/ha), leaf and seed extract at concentrations of 5g, 10g and 20g for 100ml of water. The exposure of the bees to the treatments was carried out through direct spraying of the products on the insects. For each extract, mortality and adverse effects on bee behavior were evaluated for a period of 24 hours, as well as their ability to fly after the exposure period. The aqueous extracts of neem caused mortality between 8.2% and 27.4% for leaves and 15.4% and 24.3% for seeds, significantly differing from the insecticide Thiamethoxam. The median lethal time (TL50) provided by the aqueous extracts of neem was 269.69 hours for leaf (5g/100ml), 135.39 hours for leaf (10 and 20g/100ml), and 67.89 hours for seed (5, 10, and 20g/100ml). No apparent motor disturbances were observed in bees exposed to neem extracts, with no interference in the bees' ability to fly. The aqueous extracts of neem leaves and seeds, at the concentrations evaluated, caused low mortality on A. mellifera.