Based on the original artificial diet formulation, an improved artificial diet for Helicoverpa assulta (Guenée) larvae was

developed by incorporating a proportion of chili powder as a feeding stimulant, and removing the tomato paste included in

the original diets. The effects of six artificial diets on biological parameters, nutritional indices and life table

parameters of H. assulta were investigated. The results indicate that there was no significant difference between an

artificial diet with 3% tomato paste and the control diet with respect to larval developmental period, pupa weight and

fecundity. However, larvae fed the artificial diet containing chili powder (from 05% to 4% wet weight) had significantly

higher survival rate, relative consumption rate and pupal weight than those on the control diet. The digestion of H. assulta

larvae was inhibited by the addition of ≥ 2% chili powder and adult mating ability significantly decreased when fed a diet

containing 4% chili powder. The optimum formulation was the control diet plus 1% chili powder. H. assulta fed on this diet

exhibited significantly higher fecundity and intrinsic rate of increase than those fed on other diets. The improved

artificial diet was suitable for rearing H. assulta in the laboratory and mass rearing for the commercial production of

nuclear polyhedrosis H. assulta viruses.