Comparative Studies on the Use of Nuclear Polyhedrosis Virus and Alphacypermethrin for Controlling Cotton Bollworm, Helicoverpa armigera (Hubner) (Lepidoptera : Noctuidae) on Tomato

Abstract

The efficiencies of nuclear polyhedrosis virus (NPV) and chemical insecticide (alphacypermethrin) for controlling the cotton bollworm, Helicoverpa armigera (Hubner) (Lepidoptera : Noctuidae) were compared and evaluated. Base on the number of bollworm left on tomato plants after treatment, the number and weight of the marketable tomatoes and damaged tomatoes, it was concluded that chemical application gave the most effective control. The application using chemical insecticide alternates with Heliothis NPV and using the NPV alone gave less satisfactory results. However, there was no significant difference between the use of chemical insecticide and chemical insecticide alternates with NPV for controlling bollworm on tomato. Investigation on the economic value of the two control agents demonstrated that although the cost of the virus per unit of production in the laboratory was relatively lower than that of the chemical insecticide, the overall cost of the virus application was higher. This is due to the high amount of virus suspension needed to attain the complete coverage on plant parts. However, there was no significant difference on the benefits derived from chemical insecticide application and that from the application of chemical insecticide alternated with the virus.