Temperature effects on the development and fecundity of Encarsia acaudaleyrodis (Hymenoptera: Aphelinidae), a parasitoid of Bemisia tabaci (Homoptera: Aleyrodidae) on cucumber

摘要

Development, reproduction, and life table parameters of the parasitoid Encarsia acaudaleyrodis Hayat parasitizing Bemisia tabaci Gennadius were studied at constant temperatures in the range of 20-32A degrees C under laboratory conditions. Egg-to-adult developmental time decreased from 20.3 days at 20A degrees C to 9.0 days at 32A degrees C. An average of 189.8 day-degrees was required to complete development above the lower threshold temperature (11.5A degrees C). Juvenile survival was 84, 88, 70 and 69% at 20, 25, 30 and 32A degrees C, respectively. Females of E. acaudaleyrodis oviposited means of 34.2, 54.6, 30.6 and 20.1 eggs at 20, 25, 30 and 32A degrees C, respectively, and had a mean longevity of 21.1, 14.7, 10.0 and 9.1 days at the same four temperatures. The intrinsic rate of population increase (r(m)) at the different temperatures ranged from 0.082 to 0.169, with the highest value recorded at 25A degrees C. These data indicate that E. acaudaleyrodis may be better adapted to intermediate temperatures around 25A degrees C and, therefore, could be a useful biological control agent of B. tabaci during spring and autumn when such temperatures are prevalent in Southwestern of Iran. The result could also be useful in developing a population model for E. acaudaleyrodis under field conditions.