With the blowfly season underway and experts warning that blowflies are emerging earlier each year and staying longer, effective flystrike prevention has never been more important.
 

Farmers in an Innovative Farmers field lab have found that natural approaches can form an effective first line of defence, without the environmental and health costs of chemical treatments.      
 
A group of five organic and conventional sheep farmers in the south-east of England completed a one-year trial, testing a three-part approach for flystrike prevention and treatment in 2025, keeping chemicals as a last resort only.
 
"Natural approaches to flystrike can form the first lines of defence for sheep in the UK," said Lynnie Hutchison, farmer and owner of Brickpits Organic Farm, who coordinated the trial.
 
"A sliding scale approach to flystrike from management approaches through remedies and herbal products up to chemical products can help protect people and the planet."
 
According to the Sustainable Control of Parasites in Sheep (SCOPS) blowflies are one of the most widespread ectoparasites – organisms that live on the skin or external surface of a host - affecting sheep in the UK, with surveys suggesting that every year 80% of flocks will have one or more cases of blowfly strike.                         
                   
In the UK blowfly strike costs the sheep industry around £2 million annually.
 
Earlier this month experts from SCOPS warned that changing weather patterns mean flies are emerging earlier each year and staying longer, making fixed calendar-based chemical treatments difficult to rely on alone.
 
Farmers in this Innovative Farmers field lab aimed to reduce reliance on chemical input through a three-stage decision making approach. This is in line with the July 2025 British Veterinary Association call out to vets and livestock owners to take a holistic approach to parasite control to counter environmental damage and drug resistance.
 
Many commonly used chemical treatments are highly toxic to aquatic life, and when treated, sheep excrete these chemicals in their dung, killing the dung beetles that naturally keep blowfly numbers down.
 
The sprayed fleece also attracts a lower value, with some wool processors now refusing to handle chemically treated wool. Application requires full protective clothing, and some products advise against handling treated animals for up to three months.
 
In addition, repeated use risks making these chemicals less effective over time, leaving farmers with fewer options in the future.
 
In the flystrike field lab, farmers tested a homeopathic preparation added to drinking water troughs as an early preventative measure, to explore its potential role in supporting sheep resilience as part of an integrated flystrike management approach.
 
As risk levels rose in individual groups, farmers moved on to natural spray-on products, comparing two commercial alternatives against each farm's previous conventional product. Chemical treatment was kept in reserve for the most serious cases only.
 
Across the trial, some groups of sheep completed the season without requiring further intervention beyond the homeopathic preparation and standard management. 
 
The majority of groups had herbal sprays added as the season progressed. Only two groups of lambs, whose health was already compromised, required conventional chemical treatment.
 
When treating strike patches, the farmers used natural products including tea tree oil which drove out live maggots including from thick fleece and prevented flies re-laying eggs without creating the risk of resistance.
 
The natural products tested required no personal protective equipment, no meat withdrawal periods, and presented minimal environmental risk. All five trial farmers stated they would use the protocol again.
 
"At a time when the British Veterinary Association is urging a more holistic approach to parasite control, this field lab shows farmers are already ahead of the curve.
 
Innovative Farmers exists to back farmers finding practical, nature-friendly ways to tackle issues such as this," said Innovative Farmers Programme Manager Laura Gude.
 
Building on the success of the field lab, Innovative Farmers has launched a new field lab learning network on integrated pest management. 
 
The network will create space for sharing experiences, ideas and practical solutions, while supporting fresh on-farm research to build knowledge and improve understanding and practices.
 
This learning network will also test a decision-making tool created by the field lab which aims to prevent flystrike through farm management approaches.
All information from this trial and all field labs is available open source on the Innovative Farmers website