Influence of gibberellic acid on life table parameters of Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) in laboratory conditions

Abstract

Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae), is one of the most important pests of various agricultural crops with global distribution. Influence of four concentrations of gibberellic acid (GA3) (100, 200, 400, 800 mg/kg diet) on life table parameters of H. armigera was studied at 26 ± 1 °C, 65 ± 5% RH and a photoperiod of 16 L: 8 D h. Data were analyzed based on the age-stage, two-sex life table theory. The results demonstrated significant differences among various treatments on the development time of different stages and fecundity of H. armigera. The highest mean development time of fifth and sixth instars was observed at 800 mg GA3/kg diet but was not significantly different with either control, 100 or 200 mg GA3/kg diet. According to the results obtained, life table parameters were affected by GA3. The lowest finite and intrinsic rates of increase of H. armigera were observed with 800 mg GA3/kg diet. The net reproductive rate of H. armigera on five treated diets varied from 486.21 ± 98.22 to 1269.02 ± 218.97 offspring, being lowest at 800 mg GA3/kg diet treated diet and highest in control. Different concentrations of GA3 significantly influenced mean generation time, the longest at 800 mg GA3/kg diet (49.71 ± 0.31 days) and the shortest in control (43.80 ± 0.25 days). The data obtained in this study indicate that GA3 treatment has notable effects on the development, reproduction, and survival of H. armigera particularly at higher concentrations tested.