TOXIC AND BIOCHEMICAL EFFECTS OF Beauveria bassiana AND SPINOSAD ON NURSE AND FIELD WORKERS OF HONEY BEE , Apis mellifera

This study was conducted to evaluate the toxic and biochemical effects of multiple applications with Biofly (Beauveria bassiana) and SpinTor® (spinosad) on nurse and field honey bee (Apis mellifera L.) workers under laboratory conditions. The mortality percentages of workers treated with both biopesticides were determined after 2٤ h of one, two and three daily applications. The lethal concentrations of spinosad that caused ٥0٪ mortality (LC٥0) were estimated. The effects of two biopesticides on the acetylcholinesterase (AChE) activities in heads, thoraces, and abdomens of surviving nurse and field workers were determined in vivo after 2٤ of single, two and three daily applications. The results indicated that spinosad was higher toxic than Biofly to both nurses and field worker. Also, the mortality percentages after 2٤ h of three daily applications of Biofly and spinosad were higher than that of two daily applications whatever worker type. In the same pattern, the mortality percentages after two daily applications were higher than that of single application. On the other hand, Biofly and spinosad were more toxic to foragers than to nurses after 2٤ h of one application, or two or three daily applications. Furthermore, our findings indicated that mean values of AChE activity in heads of nurse and field workers fed sugar syrup with 0, 187٫٥, 37٥, 7٥0, 1٥00 and 3000 mg L^-1 of Biofly, and 0, 2٫٥, ٥, 10 and 20 mg L^-1 of spinosad were higher than those in both thoraces and abdomens after 2٤ h of all treatments. Also, the average of AChE activities in heads was significantly (p 0٫0٥) higher than that obtained in both thoraces and abdomens whatever tested biopesticide, worker type or number of applications. In addition, tested concentrations caused various degrees of inhibition and activation in AChE activity in heads, thoraces and abdomens when compared with controls. Summed data revealed that Biofly and spinosad increased AChE activity of both worker types after 2٤ h of applications however it repeated or not.