Chemical analysis of male annihilation blocks used in the control of Queensland fruit fly Bactrocera tryoni (Froggatt) in New South Wales

The male annihilation technique (MAT) is a chemical control method designed to deplete the males available for mating in a population and thus break the reproductive cycle. In the New South Wales fruit fly control program, caneite has been used as a carrier for the lure and pesticide in MAT blocks for many years. In this paper, MAT blocks containing cuelure as an attractant and malathion as a toxicant were manufactured using two methods, namely bag immersion and roller painting, as part of the control program for Queensland fruit fly in New South Wales between September 1998 and June 2000. These blocks were sampled from storage and the field, along with historical blocks in the field deployed before the current study period. Chemical analyses of these three block types were conducted for malathion, cuelure, and raspberry ketone (a breakdown product of cuelure). There was significantly more cuelure and malathion in blocks made by the bag method than the roller method and in historical blocks. The bag method resulted in chemical concentrations closer to the desired standards. There were no significant differences between the three methods in block weight or in level of raspberry ketone. Cuelure levels declined more quickly than malathion although both chemicals were found in all blocks. For the analysis within samples, there were few significant correlations between raspberry ketone and other parameters, but there were many significant correlations between cuelure, malathion and the block weight.