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 20–32°C under laboratory conditions. Egg-to-adult developmental time decreased from 20.3 days at 20°C to 9.0 days at 32°C. An average of 189.8 day-degrees was required to complete development above the lower threshold temperature (11.5°C). Juvenile survival was 84, 88, 70 and 69% at 20, 25, 30 and 32°C, respectively. Females of E. acaudaleyrodis oviposited means of 34.2, 54.6, 30.6 and 20.1 eggs at 20, 25, 30 and 32°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 25°C. These data indicate that E. acaudaleyrodis may be better adapted to intermediate temperatures around 25°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.