1 A diapause induction and duration experiment was conducted in the laboratory on Indian Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) where 79% of individuals had extended pupal periods. At 22°C and 26°C respectively, 57% and 100% of the pupae had emerged 145 days after pupation.
2 A mathematical model was developed to investigate the interactions between diapause, migration and pyrethroid resistance frequency development in both eastern Australia and Andhra Pradesh, India.
3 The effect of diapause was different in the Australian and Indian cases, providing a mechanism to conserve resistance and susceptibility respectively.
4 For Australia, the model simulated discriminating dose data reasonably well and showed that resistance frequencies could rise prior to the pyrethroid window without invoking cross-resistance to non-pyrethroid insecticides applied to cotton.
5 The saw-toothed seasonal cycle of resistance development could be simulated in the Indian case without hypothesizing the existence of susceptible migrants.
6 The implications of‘refugia’ populations for H. armigera insecticide resistance management programmes are discussed.
Colvin, J.; Holt, J.; De Souza, K. Diapause, migration and pyrethroid-resistance dynamics in the cotton bollworm, HeIicoverpa armigera (Lepidoptera: Noctuidae). Ecological Entomology (1995) 20 (4) 333-342. [DOI: 10.1111/j.1365-2311.1995.tb00465.x]