The emergence and control of overwintering Helicoverpa armigera pupae in southern New South Wales

The extent and timing of the spring emergence of Helicoverpa armigera moths from overwintering pupae was measured in southern New South Wales (NSW). Survival was comparable to that in northern NSW, suggesting that the colder conditions did not significantly reduce the survival of overwintering pupae. Most adults emerged from mid-October to mid-November, approximately 2 weeks later than reported in northern NSW. The pattern of emergence is similar to that predicted by the HElicoverpa Armigera and Punctigera Simulation (HEAPS) model, although it tended to be earlier than predicted. Simulation of the pattern of emergence from 1990 to 2001 predicted a range of approximately 4 weeks in the date of emergence. This suggests that moths will not emerge in this part of southern NSW before October. The impact of locally used cultivation techniques on the survival of overwintering pupae supported previous findings highlighting the need for either plant line or full cultivation to ensure adequate control of overwintering pupae. Neither direct drilling nor shallow cultivation (Lillistons) provided consistently reliable control. Practical management of overwintering pupae in the region requires adequate cultivation before October.