Sobrevivência e capacidade de voo de Apis mellifera (Hymenoptera: Apidae) após o contato com resíduos de Espiromesifeno em folhas de meloeiro.

Abstract

The cultivation of melon (Cucumis melo) is an important segment of agribusiness. For its production, the chemical control of pests and the presence of the honey bee Apis mellifera (Hymenoptera: Apidae) for pollination are fundamental. Given this, one of the biggest challenges is to perform insecticide application and preserve bees in the field. Therefore, this study aimed to evaluate the survival and flight ability of A. mellifera bees after contact with residues of the insecticide Spiromesifen on melon leaves. The study was carried out in the Entomology Laboratory, at CCTA/UFCG, Pombal - PB, in an entirely randomized design, in a 4X3 factorial scheme, with two doses of Spiromesifen (0.24 g i.a/L and 0.288 g i.a/L), a positive control [Thiamethoxam (0.3 g i.a./L)] and an absolute control (distilled water), in three exposure times (1, 2 and 3h after the application of treatments). Bee mortality and behavior (tremors, prostration, paralysis, etc.) were evaluated at 1, 2, 3, 4, 5, 6, 12, 24 and 48 hours after the beginning of exposure. After 48 hours the flight ability of the surviving bees was analyzed. Spiromesifen, in the minimum and maximum doses respectively, caused mortality of 15.33% and 13.80% after 1 hour of spraying, 20.05% and 17.72% after 2 hours of spraying and 21.52% and 14.33% after 3 hours of spraying. When analyzing the survival rate, Spiromesifen showed median lethal time (TL50) lower than the absolute control, with TL50 of 112.9 hours at the minimum and maximum dose in the different times after spraying. Regarding flight ability, the number of bees that were able to fly or walk was lower than the absolute control. It was observed that 28.41%, 8.0% and 17% of the bees, when exposed within 1, 2 and 3 hours after spraying to residues of Spiromesifen at the minimum dose and 33.55% and 8.11% at 1 and 2 hours after spraying the product at the maximum dose, were able to fly. Only bees exposed after 3 hours of spraying on the leaves, at the maximum dose, were able to fly in an amount similar to the absolute witness, with 45.25%. Contact with residues of the insecticide/acaricide Spiromesifen on melon leaves was not very lethal to A. mellifera bees, but caused a reduction in the flight ability of surviving bees after the exposure period.