Department of Entomology, College of Agriculture, QUAT, Bhubaneswar-751 003, India
* Dept. of Entomology and Agricultural Zoology, Institute of Agril. Science, BHU, Varanasi - 221 005, India.
A study on effect of 13 different vegetable oils on the efficacy of cypermethrin (0.1 μg) and fenvalerate (0.2 μg) to the Helicoverpa armigera larvae collected from Varanasi during November, 1996 revealed that niger oil, neem oil and pongamia oil were prominent in enhancing cypermethrin toxicity by 50.00, 52.55 and 45.396 whereas percentage mortality due to topical application of fenvalerale (0.2 μg) in larvae pretreated with castor oil, cotton seed oil and pongamia oil was 42.85, 50.00 and 55.15, respectively. Synergistic effect of some oils were as good as the effect of piperonyl butoxide. Among seven oils tested on Guntur, Hisar, Varanasi, Coimbatore and Bhubaneswar populations of H. armigera larvae collected during the late cropping season of 1996–97 pongarnia oil, neem oil and niger oil were found to perform better over others. Effect of pretreabnent of these oils was more pronounced in Coimbatore and Bhubaneswar populations than others.
