HEAPS: A REGIONAL MODEL OF HELIOTHIS POPULATION DYNAMICS.

Abstract

Heliothis spp. are very successful as pests for a number of reasons (Fitt 1989): adult moths are highly mobile and have a high reproductive rate, larvae can utilize a wide range of host plants including most crops, and successive generations can develop resistance to pesticides. Management of such pests in commercial crops relies on regular scouting to provide information on egg and larval densities within each crop, and their likely resistance levels. We believe that the local management of Heliothis could be improved if predictions of the densities and the origin of Heliothis eggs on each crop could be made several days in advance. Regional management strategies (see Murray. these proceedings) and insecticide resistance management (see Forrester, these proceedings) would also benefit if overall seasonal predictions of likely densities for each species of Heliothis could be made with confidence. Such information would be available if we understood the population dynamics of Heliothis on a regional scale. To this end we are developing. a series of simulation models under the name "HEAPS" (HEliothis Annigera and Punctigera Simulation) (Hamilton and Fitt 1988).