Survival of the Predator Harmonia axyridis (Pallas) (Coleoptera Suitability of two Aphid Species for Development, Fecundity and: Coccinellidae) Under Laboratory Conditions

Abstract

This research carried out in the Research and Study Center of Biological Control in the Faculty of Agriculture at the Damascus University during 2013 – 2014. The aim of this research is studying the developmental time, larval survival and female fecundity of Harmonia axyridis (Pallas) reared on  black bean aphid Aphis fabae Scop. and cabbage aphid  Brevicoryne brassicae L. under laboratory conditions (25±1°C, 70±5% r.h. and 8:16 hours dark:light photoperiod). The pre-oviposition period when the predator fed on black bean aphid A. fabae was shorter (7.8 days) while it was (16.72 days) when the predator fed on cabbage aphid. There was significant effect of aphid species on the embryonic development period of predator's eggs, with an average of (3.66 days) when the predator feed on cabbage aphid, and (2.50 days) when predator feed on black bean aphid. There was significant effect of aphid species on the larval period with an average of (11.2 days) when the predator fed on black bean aphid and (10.98 days) when it fed on cabbage aphid. The fourth larval instar of predator was the most voracious stage with consumption of (81.96, 57.88 nymph) per larvae on black bean and cabbage aphid respectively. The daily consumption of the female of predator was higher than male in regardless of the prey. However, a female consumption (32.43, 32.02 nymph/day) was significantly higher than the male consumption (24.21, 21.44 nymph/day) when they fed on black bean and cabbage aphid respectively. The weight both males and females of H. axyridis reared in larval stage on A. fabae (5.67, 7.23 mg) respectively was higher than that, reared on B. brassicae (4.34, 5.57 mg) respectively.