Dept. of Zoology/Entomology, J.V.P.G. College, Barout, Meerut, U.P.
Replicted field experiments carried out at Modipuram, Meerut during 1982–85 for studying the extent of yield losses due to four lepidopterous pests revealed that one spray with chlorpyrifos 20 EC @ 2.0 Ijha resulted in a net profit of Rs. 947.35, 870.22, 700.04 and 626.03/ha in potato varieties Kufri Badshah, Kufri Bahar, Kurri Chandra-mukhi and Kurri lyoti respectively when sprayed against Agrotis ipsilon, Rs. 13.53 in Kufri Chandra Mukhi and Rs. 3.70 in Kufri Bahar when sprayed against Heliothis ar-migera (Hbn.). However,in case of Spodoptera litura (F.) and Plusia orichalcea (F.) insecticidal spray did not increase the crop yield at the infestation levels recorded.
