The objectives of Dr Byrne's visit to Australia were: 1. For Dr Byrne to present a paper to the special whitefly workshop at the World Cotton Research Conference in Brisbane, February 1994 on "Resistance biochemistry of the cotton whitefly Bemisia tabaci". 2. To assist Dr Gunning to initiate some baseline toxicological and biochemical studies to assess the resistance potential of B. tabaci on Australian cotton crops. 3. To discuss colaborati.ve research on Helicoverpa resistance biochemistry between Dr Gunning and the Rothamsted Insecticide Resistance Group.