BIOLOGY AND FEEDING POTENTIAL OF 7-SPOTTED BEETLE, COCCINELLA SEPTEMPUNCTATA (LINNAEUS) ON BERSEEM APHID, THERIOAPHIS TRIFOLII (MONELL) IN LABORATORY

Abstract

The present experiment was carried out on Biology and feeding potential of 7-spotted beetle, Coccinella septempunctata L. on berseem aphid, Therioaphis trifolii (Monell in the Biological Control Laboratory, Central Cotton Research Institute Sakrand during 2015. For this purpose, adult beetles reared in the laboratory at constant temperature and aphid collected from different crops from vicinity of Central Cotton Research Institute Sakrand were given to lady beetle for feeding. The pre-copulation, copulation and post-copulation periods were recorded as (4.4±0.69),(51.5±4.37) and (4.0±1.05) minutes, respectively. The pre-oviposion, oviposition and post-oviposition periods were averaged as 4.7±0.30, 36.6±4.88 and 5.0±1.69 days, respectively. The female deposited an average of 599.1±109.83 eggs during her life time in 30 days. Egg incubation period was noted 4.0±0.94 days with 90.35% hatching and mortality 17.56%. The larval and pupal durations were 12 and 5.2 days, respectively. The mean pupation rate % was 69.497±9.23 and the larval cannibalism rate was 30.497±9.23. The average number of pupae observed were 20.3 ± 4.47, while the male emergence was 37.47 ± 13.12 %) and the female emergence was 43.98 ± 8.24%). The result showed consumption rate of 1st, 2nd, 3rd and 4th instar larvae of C. septempunctata (22.0±4.12, 56.8±5.26, 143.8±5.93 and 289.6±9.65 aphids/day) on T. trifolii, respectively. In the same way, consumption rate of adult female (77.41±8.84/day) and male (48.94±6.29 /day) was on T. trifolii.