Toxicidade residual de Abamectina em função do tempo após a pulverização sobre Apis mellifera.

Abstract

The honey bee Apis mellifera (Hymenoptera:Apidae) is essential in citrus growing areas, one of the biggest challenges for producers is to combine chemical pest control with the conservation of bees in the field. Therefore, the objective was to evaluate the residual toxicity of Abamectin as a function of time after spraying on A. mellifera. The experiment was carried out at the Entomology Laboratory belonging to CCTA/UFCG, Pombal/PB, in a completely randomized design, in a 3 /L, one control (distilled water) and five exposure times (1, 2, 3, 24 and 48 hours after spraying), with five replications, with each experimental unit consisting of 10 adult bees. After exposure to insecticide residues, mortality and motor disorders (prostration, tremors, paralysis, reduction in feeding) of bees were evaluated at 1, 2, 3, 4, 5, 6, 12 and 24 hours. After 24 hours, the flying capacity of the surviving bees was assessed. Abamectin at the minimum and maximum doses respectively, caused around 26% and 34% of mortality after 1 hour of spraying, 16% and 18% after 2 hours of spraying, 22% and 32%, when after 3 hours of spraying, 28% and 34% after 24 hours and 40% and 48%, when exposed to residues on the leaves 48 hours after spraying. It was observed that the insecticide abamectin, regardless of dose and time after spraying, provided a median lethal time TL50 of 29.37 hours and the control provided a TL50 of 2,059.05 hours. It was observed that around 50% of the control bees were able to fly to a height of 91 cm or to the top of the tower, and for the different treatments with Abamectin, it was observed that the bees reached varying levels of height, due to their behaviors of paralysis and food reduction. Abamectin proved to be moderately toxic when in residual contact regardless of the doses and exposure interval, however, there was a reduction in the flying capacity of the surviving bees after the period of exposure to the insecticide.