تاثیرات جانبی کاربرد تیامتوکسام به‌روش تماس با باقیمانده بر شکارگر سامانه‌ی شکار-شکارگری Orius albidipennis- Aphis gossypii: مطالعه‌ی جدول زیستی

Application method of insecticides can affect efficiency of pest control and consequently side effects on natural enemies. The goal of this research was evaluation of compatibility between foliar application of neonicotinoid insecticide, thiamethoxam and Orius albidipennis (Hem.: Anthocoridae) through life table study. The cucumber leaf disks treated with three concentrations including: field rate, ½ and ¼ of it for 15s by leaf dipping and were placed upside down on agar (9gL-1) bed in petri-dishes after air-drying. Aqueous solution of distilled water and tween 80 were used as control. Then one first instar bug nymph (<24h) introduced in each petri-dish (6cm in diameter) and was transferred on untreated leaf after 24h (in 100 replication) Plectranthus verticillatus leaves were used as oviposition site and Cotton aphid, Aphis gossypii (Hem.: Aphididae) as prey. The survival rate, nymphal instars duration were recorded daily. Then adults were paired and fecundity and longevity were recorded daily until all individuals died. Egg hatching and incubation were recorded for 100 eggs randomly. The experiments were done at 25±2 °C, 65±5% RH and photoperiod of 16L: 8D hours and data were analyzed according to the age-stage, two-sex life table. The population parameters were not calculated for recommended concentration because none of treated insects couldn’t became adult. According to the results, there is a direct relationship between increasing in concentration and decreasing of pre-adult period, adult longevity, and total longevity compared to control. The pre-adult survival rate, oviposition days and total preoviposition period (TPOP) decreased by two concentrations but adult preoviposition period (APOP) decreased significantly just by half of recommended concentration compared to control. The intrinsic rate of increase (r) and finite rate of increase (λ) didn’t different in half and quarter of field rates but were different to control significantly. These values were 0.112±0.002, -0.009±0.019, 0.0166±0.01 (d-1) and 1.118±0.003, 0.990±0.01, 1.016±0.01 (d-1) for control, half and quarter of field rates respectively. The net reproductive rate (R0) and mean generation time (T) decreased by two concentrations and half of recommended concentration was more effective than quarter. These values were calculated 45.63±4.08, 0.76±0.47, 1.65±0.90 eggs and 34.10±0.23, 27.9±0.2, 30.23±0.53 days for control, half and quarter of recommended concentrations respectively. Gross reproductive rate (GRR) decreased only by half of field rate compared to control that were 53.12±4.03, 22.42±7.49 and 30.85±10.09 eggs for treatments in previous arrangement. Given that the thiamethoxam decreased seriously the population rates of predator even under 0.25 of field rate treatment, so, foliar application has adverse effects on this predator and shouldn’t be recommended in IPM of cotton aphid along with O. albidipennis.