Preferential feeding potential of zigzag beetle against Dactynotus carthami, (H.R.L), Lipaphis erysimi (Kalt.) and Therioaphis trifolii under laboratory condition

Study on preferential feeding potential of zigzag beetle against safflower aphid, alfalfa aphid and mustard aphid in the laboratory condition were carried out. The results revealed that the incubation period of zigzag beetle and the egg laid by females reared on safflower, alfalfa and mustard aphid were 625, 632 and 600 and 8.00, 6.85 and 7.60 days respectively. The difference was statistically non-significant for incubation period, while highly significant for number of eggs laid per female. The hatching percentage was 66.45, 64.50 and 67.60 was non-significant when reared on safflower alfalfa and mustard aphid respectively. The duration values in days for 1st, 2nd, 3rd and 4th instars ranged between 5.85 - 7.00, 4.00 - 5.50, 5.25 - 8.00, and 6.75 - 9.00 days when reared on safflower, alfalfa and mustard aphids, the difference were non-significant. While the pupal period ranged 3.18 to 4.15 days, pre-oviposition and. post-oviposition periods of zigzag beetle were 3.60 - 4.15 and 4.55 to 4.7 days. All the instars were found voracious feeding of all the aphid species tried. Feeding rate in terms of aphid eaten per day were highly significant, among the host aphid. Fourth instar grub consumed more mustard aphid, followed by alfalfa and safflower aphids respectively. Adult devoured more mustard aphid followed by alfalfa and safflower. It was observed that feeding rate increased with advance stages specially fourth instar grub had the highest predation rate. The feeding rate of adult on three aphid species tested increased with the age with maximum feeding rate on loth day (120.25) for mustard aphid, 12 days (110.20) for safflower aphid and 14th on alfalfa (101.15). The mean feeding rate through adult life span 65.05, 74.98 and 81.73 for safflower, alfalfa and mustard aphids respectively. Zigzag beetle grubs and adults were voracious feeders on safflower, alfalfa and mustard aphids. This beetle has great potential for the use of biological control of these three aphid species.