Toxicidade residual de Tiacloprido em folhas de meloeiro sobre Apis mellifera (Hymenoptera: Apidae).

Abstract

Bees are pollinating agents of extreme ecological, environmental and economic importance. However, one of the main problems for the maintenance of pollinators in agricultural areas has been the abusive use of pesticides in crops. Therefore, the present work aimed to evaluate the residual effect of Thiacloprid in melon leaves on A. mellifera at different times after spraying. The experiment was carried out at the Entomology Laboratory of the Center for Agro-Food Science and Technology (CCTA) of the Federal University of Campina Grande (UFCG), Campus Pombal PB. To carry out the work, adult A. mellifera workers from 05 beehives belonging to the CCTA/UFCG apiary were used. The insecticide Thiacloprid was evaluated at the minimum (150 mL/ha) and maximum (200 mL/ha) doses recommended by the manufacturer for the management of pests in the melon crop, using distilled water as an absolute control and the insecticide Thiamethoxam as a positive control. After the application of the treatments, the mortality and behavior of the bees were evaluated at 1, 2, 3, 4, 5, 6, 9, 12, 24 and 48 hours after the beginning of the exposure to the insecticides, as well as the flight capacity of the bees that survived after 48 hours of exposure. Mortality percentages were observed for the minimum dose (0.144 g i.a./L) of 54%, 57%, and 44% at 1h, 2h, and 3h after spraying and for the maximum dose (0.192 g i.a./L) at 1h, 2h , and 3h after spraying the mortality was 45% and 42%, 27%, respectively. At the minimum dose (0.144g i.a./L), regardless of exposure time, the LT50 was 38.36 hours, also for the maximum dose (0.192 g i.a./L) after 1h and 2h of spraying. At the maximum dose (0.192 g i.a./L) after the exposure time in 3 hours, the LT50 was 63.69 hours, showing a lower rate of mortality. The positive control showed LT50 of 3.17 hours at 1h and TL50 of 5.75 hours at 2h and 3h after spraying. Thiacloprid at the minimum and maximum doses was moderately toxic to adult workers of A. mellifera after contact with product residue on melon leaves, regardless of the times evaluated after spraying, and interfered with the flight capacity of A. mellifera.