Evaluation of potential resistance in seeds of different soybean cultivars to Helicoverpa armigera (Lepidoptera: Noctuidae) using demographic parameters and nutritional indices

The use of resistant cultivars is a key component of any integrated pest management (IPM) program. Here, we assess the resistance status of 10 different soybean cultivar seeds according to their effects on demographic and nutritional indices of Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) when incorporated into artificial diets. All experiments were conducted at 25 +/- 1 degrees C, 60 +/- 5% RH, and a photoperiod of 16:8 (L:D) h. Life table, reproduction, development, adult longevity, and nutritional indices of H. armigera were significantly affected by the cultivars examined. Mean developmental time of across all immature stages varied from 57 d on 'L17' to 32 d on 'Clark'. Efficiency of conversion of digested food (ECD) for old larvae ranged from 36.4% on 'Sari' to 14.8% on Sahar'. The adults that emerged from these larvae had very different rates of reproduction; the highest and lowest values for net reproductive rate (R-o) were 270 and 17 on Clark and L17, respectively. The most important demographic parameter, intrinsic rate of increase (r(m)), ranged from 0.114 on Sari to 0.09 on L17. H. armigera did not perform well on Sahar, L17, 'Gorgan3', and 'M4'. These cultivars show antibiosis resistance compared with other tested cultivars and are key candidates for field tests to determine usefulness in an IPM system