This study determined the genetic basis of pyrethroid resistance in Heliothis armigera and characterised those factors that lead to cyclical fluctuations in the frequency of resistance in field populations.

The efficacy of Bt cotton plants against field populations of Hencove, :po grinigero has not been consistent over the growing season.

Attendance to present an invited paper in the symposium "Evolution of Insecticide Resistance" on genetics of resistance in Helicoverpa at the XXI International Congress of Entomology.

Resistance is an ongoing concern with the management of Helicoverpa armigera in the Australian cotton industry.

Objectives 1. Establish lines of known parentage from available resistant strains of H. armigera (derived from VICRATS and RATS from Dr Neil Forrester, formally NSW Agriculture) 2.