Lucilia cuprina, the Australian sheep blowfly, initiates most cases of flystrike on Australian sheep. Like all insect pests, it has the potential to develop resistance to insecticide treatments. Some Australian sheep producers have reported shorter protection periods than claimed on the label of the flystrike products they have used.
On investigation, some of these cases are the result of improper application or heavy rain following insecticide application, however in a number of cases the presence of resistance has been confirmed.
This is a timely reminder for sheep producers to implement resistance management strategies to maintain flystrike protection for their flocks and slow the development of resistance within their local fly populations.
These signs indicate you might have resistance:
Strategies to slow the development of resistance to flystrike preventative chemicals by flies
(details of these strategies are provided in the first document linked below)
This document is particularly useful if you think flystrike preventative chemicals still work effectively on your property.
This document is particularly useful if you believe resistance has already emerged in the flies on your property.
Brian Horton (University of Tasmania), Peter James (University of Queensland), Deborah Maxwell (ParaBoss), Jane Morrison (MSD Animal Health), Bridget Peachey (Australian Wool Innovation), Nick Rolls (Elanco), Jane Morrison (Coopers Animal Health) and Narelle Sales (NSW Department of Primary Industries).