The Growing Challenge of Buffalo Flies in Australian Cattle Industry

Buffalo flies are currently recognized as the primary economic pest affecting the cattle industry in Australia, with annual losses estimated at $111.7 million due to production decreases, alongside an additional $60 million spent on control measures.

These blood-sucking insects not only inflict significant discomfort on cattle but also lead to skin lesions and decreased yields in both milk and meat production. Alarmingly, the issue is predicted to worsen as models indicate that buffalo fly populations will expand further into the southern states in the coming years.

The situation has been exacerbated by the recent withdrawal of Diazinon as a permissible active ingredient for controlling buffalo flies in Australia. This decision, made by the Australian Pesticides and Veterinary Medicines Authority (APVMA), was driven by safety risks, environmental concerns, and potential trade non-compliance.

A recent survey conducted by Queensland DPI revealed that 87% of 177 participants rely on ear tags, pour-ons, and sprays for buffalo fly management, with 56% noting a decline in the effectiveness of these insecticides.

Insecticide resistance—a genetic quality that allows certain insects to survive even after treatment—continues to be a major hurdle for producers. However, research efforts reported at the Northern Australian Beef Research Update Conference (NBRUC) suggest that solutions are on the horizon.

Decoding Insecticide Resistance in Buffalo Flies

Dr. Jess Morgan from Queensland DPI presented groundbreaking research aimed at uncovering the genetic basis of insecticide resistance in buffalo flies. Researchers employed traditional methods by exposing these flies to filter papers laced with varying doses of insecticides.

Dr. Jess Morgan presenting her research.

Findings indicated that certain flies were surviving exposures at “hundreds of times” the designated discriminating dosage, and there were instances of flies exhibiting a recovery from apparent death after 24 hours—a phenomenon referred to as “knockdown recovery”. This was a surprising revelation that prompted further investigation.

Identifying Genetic Mutations

By isolating DNA from the DPI buffalo fly colony, researchers uncovered two mutations responsible for 82% of the observed resistance to cypermethrin and deltamethrin treatments.

Dr. Morgan explained, “It’s the reason why you’re having to put a lot more chemical on to get an effect.” This study is newly published and provides significant insights for continued research in this field.

Additional evidence suggests that the observed knockdown recovery may be connected to detoxifying enzymes that utilize alternate pathways separate from the voltage-gated sodium channel.

Concerns have risen over the effectiveness of current insecticides. Although treatments appear to yield results initially, resistant flies may return shortly after treatment ends, raising questions about the long-term efficacy of these methods.

Innovative Approaches on the Horizon

Tim Schatz, Director of Livestock Industries at NT DAF, presented positive developments regarding a new insecticidal ear tag trialed in collaboration with Y-Tex Corporation. This tag features a brand-new combination of active ingredients, introducing a fresh possibility for buffalo fly control.

This innovative tag was tested on two groups of Brahman heifers across a week-long trial at the Beatrice Hill Research Station in the Northern Territory. Results revealed the treatment group retained significantly lower fly counts, peaking at just 15 flies per animal compared to 800 in the control group.

Mr. Schatz stated, “These results suggest that this new tag is very effective in repelling flies, making it a promising option for preventing resistance development in buffalo fly populations.”

Conclusion: A Multifaceted Approach Needed

As producers face increasing challenges with buffalo fly populations, the emphasis on research and innovation remains crucial. The findings from Dr. Morgan and Mr. Schatz highlight the importance of utilizing new technologies and methods while also revisiting older, proven solutions like buffalo fly tunnel traps, which have suffered from low uptake despite validating research-backed effectiveness.

The synergy between researchers, policymakers, and farmers will be pivotal in creating a comprehensive strategy for managing buffalo flies and protecting the Australian cattle industry’s future.