(POTENCY OF SOME BIOCONTROL AGENTS IN SUPPERSING THE POPULATION OF THE AMERICAN BOLLWORM, HELICOVERPA ARMIGERA (HUB

Abstract

The activities of the tested enzymes included acetylcholinesterase, alkaline and acid phosphatases, α and β- esterases, glututhione S- transferase, mixed function oxidase in the whole homogenates of the different instar larvae from the 3rd to the 6th of the field colony of Helicoverpa armigera (Hubner) were higher than the corresponding of the laboratory strain. The levels of enzymes activity increased gradually from the 3nd to the 6th instar larvae. Similarity in the total protein content which recorded higher in the different instar larvae of the field colony than the laboratory strain. The toxicity of the tested insecticides was higher against the 2nd instar larvae than the 4th instar larvae. Dipel was the most effective compound against the two instars larvae, whereas Bio- power recorded the least toxic compound. For toxicity index, Dipel DF the most toxic compound was selected as standard insecticides, whereas based on relative potency level, bio power the least toxic one was chosen as standard material. Bio power and Dipel DF showed the steepest toxicity line. According to the quantal scoring Dipel DF was the most pronounced insecticide for pupation. Based on inhibition of the adult emergence Proclaim recorded the most effective one. Tafaban exhibited the highest level of resistance in the 4th instar larvae of the field colony by using laboratory discriminating concentration. The highest reduction rates in the male moths caught in the pheromone traps and the larval infestation in tomato fruits were noticed in fields treated with egg parasitoid Trichogramma evanescens supported with additional belt of the same parasitoid. Predator's populations were much higher in the untreated plot than