Brendan Voss, Elders – Livestock Production Advisor, South-East SA
With high levels of moisture from long awaited winter rainfall and the warmer months approaching, this year is shaping up to be perfect conditions for the dreaded blowfly Lucilia cuprina.
Lucilia cuprina is the metallic green coloured blowfly that is the culprit for the devastating flesh eating maggots, or flystrike as we more commonly know it. Flystrike can affect sheep of all ages and sizes, and while more common in the breech area, can occur on the body, pizzle in rams and wethers, on wounds, or the poll.
The lifecycle of Lucilia cuprina begins with the adult fly seeking out a susceptible sheep to lay their eggs. These eggs develop into larvae, and are the flesh eating maggots that we are all too familiar with. The mature maggots (Larvae) drop from the infected sheep, and burrow into the soil for the next stage of development. This development is usually halted over the winter months, as soil temperatures below 15 degrees C are not favourable for the development into the pupae and onto the immature fly. Once soil temperatures warm up, usually mid spring, the immature fly emerges, developing into the adult fly and the life cycle continues.
Preventing flystrike can be done in several ways. Management practices such as shearing, crutching, and worm management decrease the areas of damp/urine stained wool and dag build up around the breech, which provide the ideal site for the adult blowfly to lay her eggs. There are many preventative chemical compounds available with several methods of application, such as spray on back liners and jetting fluids, all offering varying levels of residual. The use of such chemical compounds prior to, or at the first sight of blowflies, also has the potential to decrease fly pressure come summer/autumn months by simply breaking their lifecycle by preventing the egg developing into larvae and ultimately adult blowflies.
When considering which item to use, consider how long you want coverage for, the timing of the application, and of course and WHP or ESI on products – especially on terminal lambs or cull ewes.
The below graph ( www.flyboss.com.au) highlights the average risk periods for flystrike to occur in the Keith area. This graph can be used to assist with the timing of preventative solutions and management practices.
The Flyboss website provides great details and management advice, and is a great resource to browse at your leisure. For further information to this brief article please follow the link; www.flyboss.com.au