Buffalo flies are a major cattle pest in northern Australia. Elders Livestock Production Specialist Mark Meldrum explains the threat and how it can be managed by producers.
Buffalo flies cost the beef and dairy industries an estimated $170 million annually. If left uncontrolled, infestations can reach several thousand flies per animal, with each fly biting 20 to 40 times per day.
These bites are painful, causing irritation, production losses, and animal welfare issues. Blood loss and interruptions to grazing due to irritation can reduce live weight gain by up to 16 per cent (pc). Moderate infestations in dairy cattle (more than 30 flies per cow) can reduce milk yields by up to 0.5 litres per cow per day.
Buffalo fly feeding can lead to lesions, ranging from dry, hairless or scab to encrusted areas to severe open sores. Lesions are most commonly found beneath the eyes but can also occur on the neck, dewlap, belly, and flanks.
In northern Australia, the main fly season runs from November to April, with lower numbers for the rest of the year. Buffalo flies are most prevalent in high to rainfall coastal areas and spread into western Queensland, the Northern Territory, and northern Western Australia following heavy summer rain.
Both male and female buffalo flies feed on blood. Adult flies spend their lives on or near cattle. Eggs are laid in or under fresh dung pats and hatch within 15 to 24 hours into tiny maggots, only a few millimetres long. Maggots feed on dung and pass through three larval stages, growing to about 3 to 6 mm. This larval phase takes 4 to 5 days, with maximum survival at around 25 °C and 75 to 85 pc dung moisture. After feeding, third to stage maggots move to a drier spot, often in soil near the dung, and form a brown puparium about 4 to 5 mm long. Adult flies emerge after 3 to 5 days and live for 2 to 3 weeks if they find suitable cattle hosts. During peak season, the life cycle takes 12 to 14 days from egg to egg.
Buffalo flies depend on cattle for blood and usually die within a couple of days if separated from a host. Optimal conditions include annual rainfall above 500 mm and daily temperatures of 27 to 30 °C. Fly numbers peak in late summer and early autumn.
Buffalo fly control combines chemical and non-chemical methods. Chemical options include insecticidal ear tags, pour treatments, sprays, and backrubbers, with rotation of chemical groups to prevent resistance. Non-chemical methods include dung beetles, which bury dung and reduce breeding sites, and select cattle with natural resistance.
Chemical control
Insecticidal ear tags release chemicals over several months. Rotate between chemical groups (e.g., organophosphates and synthetic pyrethroids) to minimise resistance. With Diazinon tags no longer available, rotation is limited to two active groups:
- Macrocyclic Lactones (ML): Abamectin, Piperonyl Butoxide (technical)
- Synthetic pyrethroids: Betacyfluthrin & Piperonyl Butoxide
Pour-on insecticides are applied along the animal’s back and provide protection for only a few weeks.
Backrubbers allow cattle to self-apply insecticide by rubbing against treated ropes or mats.
Sulphur lick blocks can help control buffalo flies. Sulphur disrupts the flies’ exoskeleton, causing dehydration and death. Some blocks also include garlic, which contains allicin, shown to further reduce fly populations.
Sulphur is a natural insecticide that can kill external parasites like buffalo flies. Studies show sulphur supplementation reduces fly numbers, especially when combined with other methods.
Lick blocks work best as part of an integrated parasite control program, alongside insecticide treatments.
Distribution
Buffalo flies are mainly a pest in northern cattle but are spreading south as the climate warms. They have been found as far south as Maitland in eastern NSW and as far west as Narromine, Dubbo, and Bourke during the wet years of 2010–11.
In northern Australia, the main fly season runs from November to April, with lower numbers for the rest of the year. Buffalo flies are most prevalent in high-rainfall coastal areas and spread into western Queensland, the Northern Territory, and northern Western Australia after heavy summer rain.
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