اثر مدت زمان ذخیره سازی شفیره‌های زنبور Encarsia formosa (Hymenoptera: Aphelinidae) بر کارایی آن در کنترل سفیدبالک Trialeurodes vaporariorum (Hemiptera: Aleyrodidae)

The parasitoid wasp, Encarsia formosa Gahan (Hymenoptera: Aphelinidae) is the most important biological control agent of Trialeurodes vaporariorum Westwood (Hemiptera: Aleyrodidae), commercially produced and used to control this pest in greenhouses. Due to importance of E. formosa and its mass rearing under laboratory conditions, evaluating the condition for pupal storage on adult efficiency is crucial. In this study, the effect of pupal storage duration (5, 10, 15, 20, 25 and 30 days) of E. formosa at temperature of 4 °C and dark completely conditions on some quality control parameters, such as adult emergence time from pupae, percentage of adult emergence, total parasitism, and female adult longevity were investigated. After the storage period, the pupae were transported to laboratory condition at 25±1 °C, 60±5% RH and a photoperiod 16: 8 h (L: D). A control treatment (without pupal storage) was also included. The treatments were started with 10 cohort, each with 100 pupae. The parasitism rate and female adult longevity was investigated using 30 female adults. The results showed that the maximum duration of adult emergence from pupae was 6.62±0.03 and 6.53±0.02 days for the 5- and 10-days storage treatments, respectively, which significantly differed from the control (6.82±0.03 days). The minimum value for this parameter was 3.96±0.05 days for the 30-days storage treatment. The highest percentage of adult emergence was observed for 5-days (88.85±0.93 %) and 10-days (85.63±1.06 %) storage treatments, which was not significantly differed from the control (96.2±0.55%). However, the percentage of adult emergence decreased with increasing storage duration. The total parasitism (= number of hosts parasitized) for adults that their pupae were stored for 5 days (79.30±2.9) and 10 days (72.01±2.5) were significantly lower than the control treatment (145.5±5.76). The lowest total parasitism was 7.82±0.73 for the 30-days storage treatment. Female adult longevity of E. formosa was 16.35±0.04 and 16.38±0.31 days for 5- and 10-days storage treatments, respectively, which were significantly lower than the control (22.36±0.86 days) but significantly higher than the other treatments. The results of this research showed that increasing the duration of pupal storage negatively affects some quality control parameters, and storing pupae for more than 10 days is not recommenced. Therefore, for optimal management of T. vaporariorum populations, it is the best to use E. formosa adults whose pupae have been stored at 4 °C for a maximum of 10 days.