Investigations into the toxic and repellent effects of propiconazole on the wool-digesting carpet beetle larvae Anthrenocerus australis (Coleoptera: Dermestidae)

Previous work had shown propiconazole applied to wool gave a protective effect against the keratinophagous insect larvae of the Australian carpet beetle Anthrenocerus australis. To elucidate the mode of action of propiconazole on Anthrenocerus australis, repellency trials were carried out using untreated control and propiconazole-treated wool. A reversible choice experiment using Petri dishes, and an irreversible olfactometer choice experiment were carried out. Treated surface repellency trials were also carried out. No repellency effect was detected with any of these experiments. Direct contact experiments were carried out by application of propiconazole solutions directly to Anthrenocerus australis larvae and by feeding larvae propiconazole-treated wool. No short or long-term toxic effects were detected, and subsequent feeding on untreated wool was not reduced. These results suggest an anti-feeding and/or gut-specific mode of action of propiconazole on Anthrenocerus australis that is likely to be different to that of the commonly used wool insecticides. This provides an opportunity to research a new approach to the control of this wool pest.