The Effect of Different Diets and Storage Period of Encarsia formosa Gahan on its Longevity and Efficiency

Regarding the importance and high potential of Encarsia formosa Gahan (Hymenoptera: Aphelinidae) for control of the greenhouse whitefly, Trialeurodes vaporariorum Westwood (Homoptera: Aleyrodidae), the effect of different diets and storage of the parasitoid at low temperatures on its longevity and efficiency was studied. The average longevity of the parasitoid on different diets including honey-syrup 15%, honey-syrup 10%, sucrose syrup 15%, honeydew of whitefly were significantly different at 1% from distilled water and control (without water and food) treatments. Change in honey-syrup concentration at a range of 5% did not affect the longevity of the parasitoid. The honeydew and sucrose-syrup treatments were not significantly different. This was probably due to the relative similarity of food quality of these two diets. Storage of host parasitized nymphs containing pupae of 1-2 days-old of E. formosa at 8±1°C affected the emergence rate and efficiency of adult parasitoids. Four treatments including the pupae of parasitoids in 4th nymphal instars of the greenhouse whitefly were stored at 8±1°C for 5, 15, 25 and 35 days. Control treatment included pupae of parasitoid that were held at room temperature, 24±4°C. Host nymphs were parasitized by the parasitoids emerging from all treatments. The average parasitized nymphs by parasitoids emerging from 5, 15 days and control treatments were not significantly different at 1 %.