ISHS Acta Horticulturae 696: VII International Symposium on Temperate Zone Fruits in the Tropics and Subtropics - Part Two
STUDIES ON SEASONAL ABUNDANCE OF WOOLLY APPLE APHID AND ITS NATURAL ENEMIES IN THE MID HILLS OF HIMACHAL PRADESH |
| Authors: | A. Sood, P.R. Gupta |
| Keywords: | apple, woolly apple aphid, Aphelinus mali, coccinellids |
| Abstract:
Studies on seasonal abundance of woolly apple aphid, Eriosoma lanigerum (Hausmann) and its natural enemies on apple were undertaken during April 1997 to March 1999 at Solan, under mid hill conditions of Himachal Pradesh. Continuous monitoring of the population at weekly intervals revealed two peaks of aphid activity on apple trees, one before August and other after mid October (mainly in November- December). While activity of the parasitoid, Aphelinus mali, well synchronized with the activity of woolly apple aphid, the predator population remained low and did not show distinct pattern of association with the aphid activity. Coccinellids appear to show less preference to the woolly apple aphid. In multiple regression analysis, natural enemies and weather parameters (maximum and minimum temperature, rainfall and relative humidity) contributed only 38.6 and 33.9 per cent towards population build-up. Factors other than these, like physiological state of the tree and aphid movement between arboreal and subterranean parts of the tree, also appear crucial for population build-up. | |
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