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There are a range of spray-on products that can be used to protect sheep during periods of high flystrike risk.

The table below indicates the advantages and disadvantages of using spray-on products.





  • Can be used for long wool flystrike prevention
  • Ease of application—can be applied with a power-asisted applicator, which helps ensure consistency and reduces operator fatigue
  • Products ready for direct application so no additional water required
  • Disposal of empty containers only
  • Cost
  • Applicator must be matched to product

Video - best practice application of spray-on flystrike protection.

DownloadDownload E90_Sprayon_Web_video_small_WMV_4x3.wmv (6.3 MB)

Spray-on flystrike prevention

Spray-on products are easier, more convenient alternatives to hand jetting. These products are usually applied undiluted along the backline of the sheep, but in some situations, additional bands are sprayed around the breech area. The principal advantage of the spray-on products is their ease of application as no additional water is required. This is a particular advantage in the drier and more isolated areas where large volumes of water may have to be carted long distances for wet applications. These products may be taken to the sheep.

Many of these products can be applied using power-assisted (compressed air or LPG gas cylinder) applicators. This assists with consistent delivery of the selected dose, ensures rapid and reliable refilling of the gun and reduces operator fatigue. For smaller flocks the simple manual squeeze type applicators available offer a cheap and easily portable means of application. It is essential that only applicators approved for particular products are used and calibrated according to directions for the product of choice, before being used on the sheep.

There are several spray-on products registered for application to long wool sheep for blowfly control. The active ingredient in these is cyromazine, dicyclanil or alpha-cypermethrin. Dicyclanil products may also be used off-shears. Labels for products based on these insecticides carry flystrike prevention claims of 11, 18–24 and 10 weeks respectively. It is essential to follow the label instructions with regard to dose rate and target area on the sheep for the application. Fan nozzles can deliver at least 15 cm-wide spray bands with each pass if held 20–25 cm above the wool during application. The aim is to achieve total coverage of the areas needing protection (unlike lice backline treatments, flystrike spray-ons do NOT spread and provide protection beyond where they are applied). If two or more bands are applied there should be some overlap.

Some products stipulate dose rates based on bodyweight, whereas dose rates for others are based on wool length. In mobs where sheep vary widely in bodyweight, cost savings, more efficient application and reduced residues might be possible if the mob is drafted into several weight classes. Otherwise, it would be prudent to set the dose to the weight of the heaviest sheep in the mob. Similarly, where dose rate is determined by length of wool growth, similar sheep should be drafted into treatment groups. If this is not feasible for mobs with mixed shearings or where unshorn young sheep vary by more than two months in ages it would be prudent to treat according to the longest wool length.

It is very important to consistently apply these products over the full body length, i.e. poll to tail along the back of the sheep, equally along each side of the spine of the sheep exactly as specified on the label. Failure to treat the specified target area may lead to reduced or incomplete flystrike protection.

These products are not suitable for the treatment of struck sheep or sheep with soiled crutches. Struck sheep should be drafted off and strikes shorn and treated as recommended with a registered flystrike dressing. Daggy sheep should be lightly crutched to remove faecal material and urine stain prior to treatment.


Users of agricultural or veterinary chemical products must always read the label and any permit, before using the product, and strictly comply with the directions on the label and the conditions of any permit. Adhere to the withholding periods (WHPs) and be aware that the export slaughter interval (ESI) may be longer than the WHP.