Morphological and biological notes on Encarsia meritoria Gahan (Hymenoptera, Aphelinidae), a parasitoid of Trialeurodes vaporariorum (Westwood) (Homoptera, Aleyrodidae) new in Europe

Encarsia meritoria Gahan, a Neartic species recorded only in the USA, was found naturally occurring in Catalonia (north‐east Spain) in 1987. The morphology of immature stages, the rate of development in the range 12°C‐34°C, the longevity and fecundity at 24°C and some observations on its searching and host feeding behaviour are presented in this paper. Mean development times from egg laying to adult emergence ranged from 75 days at 12° C to 11 days at 28°C. The Lower Developmental Threshold computed from linear regression equations was 9°C. Females laid an average of 198 eggs (range 89–330) in an average of 34 days (longevity range 19–54 days). The intrinsic rate of increase at 24° C was 0.1717, slightly greater than the rm of T. vaporariorum and smaller than the values reported for E. tricolor and E. formosa, which is not very promising for biological control. However, this may not be a definitive conclusion, because factors other than those considered in our experiments may play an important role infiel...