Suppression of populations of Australian sheep blowfly, Lucilia cuprina (Wiedemann) (Diptera: Calliphoridae), with a novel blowfly trap

The Australian sheep blowfly, Lucilia cuprina initiates more than 85% of fly strikes on sheep in Australia with an estimated average annual cost of A$280 million to the Australian wool industry. LuciTrap® is a commercially available, selective trap for L. cuprina consisting of a plastic bucket with multiple fly entry cones and a synthetic attractant. The impact of LuciTrap on populations of L. cuprina on sheep properties in five Australian states was evaluated by comparing L. cuprina populations on paired properties with and without LuciTraps over seasons when significant fly populations could be expected. Twenty-four comparisons (trials) were conducted over four years. During times of ‘higher fly density’ (when the 48 h geometric mean of trap catches on the control property was greater than five L. cuprina), the overall geometric mean trap catches for control and trapped properties differed significantly (P<0.001) with mean trap catches of 19.4 and 7.74 L. cuprina respectively. The selectivity of the LuciTrap was confirmed with 59% of all trapped flies being L. cuprina. Chrysomya spp. and Calliphora spp. constituted 9.3% and 1.1% of the catches with a variety of other flies (mainly Sarcophagidae and Muscidae) providing the remainder (31%). L. sericata was only trapped in Tasmania and made up 7.7% of the Lucilia spp. catch in this State. Seventy-two percent of the trapped L. cuprina were female. The deployment of LuciTrap on sheep properties at one trap per 100 sheep from the beginning of the anticipated fly season suppressed the populations of L. cuprina by 60% compared to matched control properties. The LuciTrap is a selective and easy to use fly trap and constitutes an effective, non-insecticidal tool for use in integrated management programs for L. cuprina.

Nuisance fly management on cattle feedlots

The Project will assess the impact of chemical applications and more targeted cleaning on nuisance fly control in feedlots. It will develop and evaluate new, biological agents for the control of nuisance flies and explore options for integration of these.

Chemical containment and eradication of screw− worm incursions in Australia

Screwworms are obligate, invasive parasites of warm-blooded animals. The female flies lay batches of eggs at the edge of wounds or other lesions. These eggs hatch to larvae or screw-worms which feed on affected animals for 6-7 days, burrowing deeply into subcutaneous tissues and causing severe trauma to animals, production loss and potentially death. Susceptible sites include wounds resulting from management practices such as castration, de-horning and ear tagging and lesions caused by the activities of other parasites such as buffalo flies and ticks. The navels of the new born and the vulval region of their mothers following parturition are highly susceptible and body orifices such as nose and ears are also frequent targets for ovipositing screwworm flies. The Old World screw-worm, Chrysomya bezziana (OWS) is considered one of the most serious exotic insect pest threatening Australia's livestock industries and is endemic in a number of our closest neighbouring countries. New World screwworm (NWS), Cochliomyia hominivorax, endemic to South America, has also entered Australia on at least 2 occasions. Many tropical and subtropical areas of Australia are suitable for the establishment of OWS and the potential range is expected to increase with climate change. The Australian screwworm preparedness strategy indicates a program of containment with chemical treatments followed by eradication of OWS using sterile male release and parasiticides. However, there is no longer an operational OWS sterile insect screw-worm facility anywhere in the world and establishing a large scale production facility would most optimistically take at least 2 years. In the interim, containment would be almost totally dependent on the availability of effective chemical controls. A review of chemical formulations available for potential use against OWS in Australia found that currently only one chemical, ivermectin administered by subcutaneous injection (s.c.) is registered for use against OWS and that many of the chemicals previously shown to be effective against OWS were no longer registered for animal use in Australia.18 From this review a number of Australian-registered chemicals were recommended as a priority for testing against OWS. The Australian Pesticides and Veterinary Medicines Authority (APVMA) can issue an emergency use permit for use of pesticides if they are registered in Australia for other animal uses and shown to be effective against OWS. This project tested the therapeutic and prophylactic efficacy of chemicals with potential for use in the treatment and control of OWS.