Lethal and sublethal effects of insecticides azadirachtin, flonicamid, thiacloprid and thiocyclam on parasitoide wasp Habrobracon hebetor

Habrobracon hebetor is one of the most important parasitoid wasps of larvae of many lepidopteran pests, particularly the family Noctuidae. In this study, the lethal and sub-lethal effects of four insecticides including azadirachtin, flonicamid, thiacloprid and thiocylcam were examined on adult parasitoid. Parasitoid larvae were reared on last instar of Mediterranean flour moth in a growth chamber at 27±2°C, relative humidity 70±5 and a photoperiod of 16 h light and 8 h dark. Bioassay tests on adults were conducted based on contact method and sub-lethal effect studies were done based on demographic tests. Estimated LC25 values for azadirachtin, flonicamid, thiacloprid and thiocylcam were 277, 269 and 44.1 mg ai per l, respectively. Estimated LC50 values for azadirachtin, flonicamid, thiacloprid and thiocylcam were 551, 467 and 15.3 mg ai per l, respectively. The LC25 and LC50 values for azadirachtin were not estimated because mortality was 19% at a rate, which was three times the field rate (6000 ppm). Thiocylcam was the most toxic component against females. The intrinsic rate of increase (rm) for control and azadirachtin, flonicamid, thiacloprid and thiocylcam were 0.26±0.005, 0.24±0.004, 0.23±0.005, 0.22±0.04 and 0.21±0.005 (day-1), respectively. Gross reproduction rate (GRR) for control and azadirachtin, flonicamid, thiacloprid and thiocylcam were 93.07±2.37, 82.99±1.77, 78.94±1.17, 69.84±0.85, and 62.01±1.01, (egg), respectively. Based on the results, azadirachtin and flonicamid were the least toxic compounds. If results were confirmed by field tests, the pesticides may be associated with the biological control agents in integrated pest management programs.