11 Mar 2020
Miniature parasitic wasps actively seek out the pupae of nuisance, biting flies that spread the bacteria responsible for summer mastitis and New Forest eye on farms.
Spalangia cameroni on a house fly pupa.
An enterprising farm vet practice has established a thriving business selling “flies” to dairy farmers.
Although branded Friendly Flies, the insects are actually miniature parasitic wasps (Muscidifurax raptor and Spalangia cameroni), which actively seek out the pupae of nuisance, biting flies that spread the bacteria responsible for summer mastitis and New Forest eye on farms.
Once located, the friendly flies lay their own eggs inside the nuisance fly pupae. When those eggs hatch, the parasitic wasp kills and eats the developing nuisance fly maggot, and then hatches to continue the cycle of predating on more nuisance flies.
The all-natural parasitic fly control solution, which can help reduce on-farm insecticidal and antibiotic use, and increase biodiversity, is being offered by LLM Farm Vets – one of the first farm-only vets in England, which now looks after some 50,000 cows at five sites in the north-west.
Vet Tom Jackson of LLM Farm Vets explained the practice held a Defra licence to import the flies from the US, where they are extensively used to control nuisance fly species on poultry, as well as at ruminant and pig farms.
The friendly fly species are native to the UK, but naturally found only in tiny numbers that are insufficient to be effective on large nuisance fly populations on farms, so their release does not pose any environmental threat.
Mr Jackson said he understood LLM Farm Vets to be the only company supplying friendly flies to the ruminant sector in the UK.