Ecology, Environment and Conservation Paper

FEEDING POTENTIAL OF COCCINELLA SEPTEMPUNCTATA LINN. ON MUSTARD APHID, LIPAPHIS ERYSIMI KALT.

Arvind, B.L. Jat, A. Chand1, K. Kadawla, S. Kumawat and S. Kumar

Abstract

Mustard is an important Rabi season oilseed crop. In India, mustard is one of the most important oil seed crops after groundnut. The oil content in mustard seed ranges from 32 - 40 per cent. On the basis of economic losses, mustard aphid is considered to be a key pest. The exploitation of biocontrol agents is considered as a suitable alternative to the use of chemical pesticides. Coccinellid beetles, among the various predators, play a crucial role in controlling harmful insect pests in the natural environment. A widely distributed species of coccinellid beetle, Coccinella septempunctata, has been found to be highly effective in combating different insect pests. The feeding potential of mustard aphid predator, C. septempunctata was studied in ambient conditions by ensuring food supply to them in the form of varying number of aphids, i.e., 50 to I instar, 75 to II instar, 100 to III instar, 125 to IV instar and 150 to adult daily in morning hours (8-10 AM). The observations on number of aphids consumed were recorded after 24 hours of food provided to the predator. A separate jar containing 100 aphids without predator was kept as control. The first instar larva (grub) of C. septempunctata consumed 20.30 aphids, second instar 31.10 aphids, third instar 84.20 aphids and fourth instar 119.30 aphids per day ranging from 20 - 28, 25 - 35, 43 - 159, 112 - 133 aphids per day, respectively. The highest number of aphids per day was consumed by fourth instar grub i.e., 119.30 aphids/ day. During the total grub period a single grub consumed on an average of 254.90 mustard aphids. The non-starved adult of C. septempunctata consumed 94.20 aphids and 24 hours starved adult consumed 110.20 aphids in 24 hours ranging from 90 - 101 and 99 - 118, respectively.