Effect of Lipaphis erysimi (Kaitenbach) Numbers on the Feeding Potential of Coccinella septempunctata Linnaeus

Effect of population density of mustard aphid Lipaphis erysimi (Kaitenbach) on the feeding potential of second instar larva and adult of Coccinella septempunctata Linnaeus were studied under laboratory conditions. Aphids at various densities, viz., 10, 20, 30, 40, 50, 60, 70, 80, 90 and 100, were provided to second instar larva and adult of C. septempunctata in two separate sets of experiments. Significantly highest (32.25) number of aphids were consumed by the second instar larva after 12 hour of release at population level of 90 aphids, which was on a par with population levels of 70 (26.050), 80 (30.75) and 100 (31.25) aphids. Significantly highest feeding rate of 2.68 aphids/hour was recorded at 90 aphids, which was on a par with population level of 80 (2.55) and 100 (2.60) aphids. Similarly, significantly highest (55.00) number of aphids was consumed by the adult after 12h of release at population level of 100 aphids, which was on par with population level of 60 (45.00), 70 (45.00), 80 (44.50) and 90 (52.00) aphids. Significantly highest feeding rate of 4.57 aphids per hour was recorded at population level of 100 aphids, however it was on par with population level of 90 (4.33) aphids. The studies revealed that the feeding potential of larva and adult of C. septempunctata significantly increased with increase in population density of mustard aphid.