Prevalence and impact of entomogenous fungus, Entomophthora aphidis Hoffmann on three important aphid species infesting rapeseed in the Palam Valley of Himachal Pradesh (India)
Abstract
The impact of entomogenous fungus, Entomophthora aphidis Hoffmann, parasitising three aphid species, viz., Lipaphis erysimi (Kalt.), Brevicoryne brassicae (Linn.) and Myzus persicae (Sulz.) on rapeseed, was studied during two crop growing seasons. The respective per cent parasitisation of these three serious aphid pests by E. aphidis varied from 2.65–4.93, 1.53–4.36 and 2.36–4.67 during 1992–93; and 2.85–7.49, 1.12–7.30 and 0.53–1.32 in 1993–94. Peak parasitisation of aphid species was recorded in the first fortnight of March, when the temperature varied from 14.7°-18.50°C (maximum), 5.3°-8.70°C (minimum), and relative humidity from 45.5–59.5 per cent.
