Determination of the toxic effects of seed coated pesticides used in cotton on honey bee

Objective: The aim of this study was to determine residues of some active substances (clothianidin, metalaxyl-M, azoxystrobin ve fludioxonil) in the seed pesticides used for cotton production cultivated in large areas on honey, pollen and bee, and their effects on honey bees. Material and Methods: Cotton seeds were sown after they were covered with an insecticide (clothianidin) and a fungicide (azoxystrobin+ fludioxonil+ metalaxyl-M). In order to determine the effects of these pesticides on bees, dead bees were collected in front of and around the beehives in the plots at regular intervals for 26 days. Dead bees were counted in the laboratory and the data were recorded. In addition, 150 flowers from approximately 100 plants from each plot were collected in plastic tubs during the flowering period, and honey samples were taken from all beehives on the last day of the experiment. After pollen, bee and honey samples were extracted with the modified QuECheRS method, they were analyzed by LC-MS/MS. Results: The average number of dead bees in the net greenhouse and open field was determined as 129.98 and 4.92 in the clothianidin plot, 123.44 and 7.94 in the azoxystrobin + metalaxyl-M + fludioxonil plot, and 83.54 and 4.77 in the control plot, respectively. 4.27 and 1.57 µg/kg clothianidin, 0.33 and 0.11 µg/kg fludioxonil were detected from dead bees and honey in the greenhouse plots, respectively. In dead bee samples taken from open field plots, 4.13 µg/kg clothianidin, 0.33 µg/kg fludioxonil; 1.61 µg/kg clothianidin and 0.19 µg/kg fludioxonil were detected in honey samples. In the pollen samples obtained from the flowers of cotton plant, 6.00 µg/kg clothianidin and 0.25 µg/kg fludioxonil were detected. Azoxystrobin and metalaxyl-M were not detected in honey, pollen and dead bee samples that were analyzed for pesticide residues. The daily temperature values obtained during the study were at the optimum value for honey bees. Conclusion: It has been determined that the systemic seed pesticides used in the cotton plant are transferred to the pollen and therefore the bees fed with the pollen die. Systemic seed pesticides were found in pollen during the flowering period, approximately two months after sowing the seeds.Furthermore not only bees but also humans who consume honey as food can be exposed to pesticides. Keywords: Cotton, Seed Coated Pesticides, Honey Bees, Pollen, Honey