Level of national risk of blowfly strike: 

Current risk: Medium

The current unsettled weather, and further forecast make it difficult to forecast the end of the blowfly season. As stated on the NADIS site: 'In upland areas the strike risk is likely to be close to zero, but in lowland areas, the persistent higher than average temperatures this autumn mean that some strike risk will remain until the temperatures fall consistently below about 11°C. This could potentially result in strikes through to early November, particularly in southern and central England.' The risk of blowfly strike can still be viewed as medium.

Take action: Growing fleeces make sheep increasingly susceptible to flystrike. Depending on when preventative products were applied, it may be appropriate to reapply to ensure appropriate protection; CLiKZiN delivers 8 weeks' protection with a short meat withdrawal period of 7 days.

Please note: The NADIS forecast now adopts a new colour code, with red indicating a clear risk from strike and black being used to indicate the highest risk.

A significant number of strikes are being reported in many regions of the country. It is crucial to plan to protect animals against flystrike.

Check the level of blowfly risk in your area:

Strike first against blowfly

Blowfly strike control in sheep

Strike first!

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Elanco blowfly tracker for reporting blowfly strikes

Seen blowfly strike?

Report a case of blowfly strike to track this on our blowfly tracker.

Elanco blowfly tracker for reporting blowfly strikes

Check strikes reported

Check the number of strikes reported in your county using the Blowfly Tracker

Sources and acknowledgements

The model used to generate these predictions uses Met Office recordings of daily temperatures and rainfall, along with a detailed understanding of fly biology and sheep susceptibility to strike, to forecast the patterns of strike incidence. The model is highly accurate and tests have shown that it can effectively explain patterns of strike in sheep flocks1,2.

The risk level relates to the number of affected sheep expected collectively for all flocks in a region – and the expectation is that most of these sheep would be treated. If sheep were all untreated, incidences would be about 10x higher than the predictions. Each predicted strike level relates to the period from one update to the next.

Risk data provided by Professor Richard Wall BSc, MBA, PhD from the University of Bristol.

  1. Wall et al, 2000, Sheep blowfly strike: a model approach. Res Vet Sci, 69, 1-9.
  2. Wall et al, 2002, Development and validation of a simulation model for sheep blowfly strike. Med Vet Entomol., 16, 335-346