مطالعه‌ی اثرات زیرکشندگی سم آبامکتین روی کنه‌ی شکارگر (Acari: Phytoseiidae) Neoseiulus californicus در شرایط آزمایشگاهی

In integrated pest management programs,The sub-lethal impacts of pesticides are the most important factors in the modifying effectiveness of a natural enemy to control the host or prey population. In present study, the sub-lethal effects of Abamectin (Vertimec®, EC1.8%) with three concentrations 4.97, 9.43 and 14.94 µl/l (LC10, LC20 and LC30) and control on the biological parameters of Neoseiulus californicus McGregor were investigated at laboratory conditions with 25 ± 2 ºC, relative humidity of 65 ± 5 % and a photoperiod of 16: 8 (L: D) h. Thus 60 of the same-aged eggs were collected randomly from treated females with different concentrations and control, then individually placed into leaf discs without any pollution. After adult’s emergence, number of offspring produced by each female per day was recorded until the death of last individual. Data analysis was performed using Age-Stage Two-Sex Life Table theory. According to the results, duration of different life stages and fecundity of N. californicus was significantly affected by different treatments. Duration of total immature stages in control and LC10, LC20 and LC30 treatments was 6.75, 8.53, 10.25 and 12.53 day, respectively. As concentration increased, duration of adult longevity significantly decreased. The duration of oviposition period in control, LC10, LC20 and LC30 concentartions was 13.79, 8.24, 7.12 and 5.07 (day), respectively. Furthermore, total fecundity of N. californicus was significantly affected by different treatments and with increasing concentration, the recorded values for this parameter was decreased (28.07 eggs in control and 6.47 eggs in LC30). The highest and lowest values of the intrinsic rate of increase (r) were recorded in control (0.205) day-1 and LC30 (0.021) day-1, respectively. Furthermore, the value of the finite rate of increase (λ) varied from 1.021 (day-1) in LC30 to 1.228 (day-1) in control. The net reproductive rate (R0) of N. californicus decreased from 15.72 (offspring) in control to 1.70 (offspring) in LC30. The value for mean generation time (T) varied from 13.38 day in control to 25.24 day in LC30. The results showed that the release of biological control agents should be done at intervals after Abamectin spraying to reduce the adverse effects of the toxin on natural enemies.