Know your fly sprays!

I can't remember an Easter as nice as the one we're currently having but the flies have come out with a vengeance! Poor Charlie gets mithered by flies particularly around his head and eyes which means each year I go through the same process of trying to find a fly spray that actually works! One trip to the saddler's and it is very overwhelming the number of options for fly control. I thought it would be useful to give my top tips when choosing a fly repellent and explain some of the most common ingredients so you can have a bit more knowledge when choosing the best for your horses.

Tip Number 1:

  • Try to ignore marketing hype and don't get misled by big brand claims.

Tip Number 2:

  • Know your ingredients. This is essential to get the right choice for your horse (see below). Insecticides kill the insects, repellents only repel them.

Tip Number 3:

  • Look at the percentages. The only way to compare two different brands of fly repellent is to look at which one has the higher % of ingredients.

Tip Number 4:

  • Natural is not always better. Don't assume that natural fly repellents are as effective as synthetic ones, plus they are only repellents so will never be as effective as an insecticide.

Tip Number 5:

  • You get what you pay for. The more expensive repellents generally have higher concentrations of ingredients in and therefore are more effective and last longer.

Tip Number 6:

  • ALWAYS DO A PATCH TEST! Every year I have to examine horses that have had an allergic skin reaction to a new fly spray, in severe cases this can lead to misery and take months for the skin to recover. The skin in the armpit is generally quite a good area to do a patch test on. Wait 24 hours to check for a reaction.


Some common ingredients:

Permethrins and Cypermethrins – insecticides

(Deosect, Switch)

These are considered the strongest fly spray ingredients and their use is regulated so most types require a prescription from the vets. They are synthetic ingredients that actually kill the insects by affecting the nervous system. Depending on the product chosen they are applied every 2-4 weeks and are either diluted with water and sprayed on or poured directly along the neck and rump.

I've used both Deosect and Switch on Clover who has very sensitive skin and prone to sweet itch and found both to be effective. They would work best combined with a good fly rug and mask. Although they are more expensive compared to other fly repellents because of their longer activity they are used much less frequently so in my experience are more cost effective.


DEET – repellent

Power Phaser, NAF Power

DEET is a powerful synthetic solvent – don't use it near tack as it can dissolve leather. Check the percentage of DEET on the product label, higher percentages will be more effective and last longer. DEET is considered very safe and effective at repelling flies and mosquitoes.

PMD/ p,mentane 3-8 diol/ citriodiol/ citrepel – Repellent

Naf-off 1%, Barrier Super Plus 1%, Lincoln Fly Stoppa 0.8%

PMD is a natural chemical from lemon eucalyptus leaves. PMD has had a lot of research into the effectiveness and many organisations deem it to be as effective as synthetic compounds such as DEET when used in high enough concentrations. Often the concentrations in commercial fly repellents are not enough to have long lasting repellent activity. It does smell lovely though!

Similar to citronella PMD can cause skin reactions in sensitive horses so always do a patch test first.

Citronella – Repellent

Many different products at undisclosed concentrations.

Citronella is a natural oil extracted from the lemon grass plant and used for its fly repellent activity. Many products contain citronella which can be easily identified from its strong scent. Unfortunately the concentration of citronella is often not disclosed making it difficult to compare products. It does need to be reapplied regularly to remain effective.

Ethyl Butacetylaminopropionate/ IR3535® - repellent

Power Phaser 4.9%, effol horse fly blocker 10%

Ethyl Butacetylaminopropionate or IR3535® is a synthetic fly repellent chemical. It provides long lasting repellent activity against flies and Power Phaser claims to be effective even when horses sweat so may be a good choice for during competitions, long rides or strenuous exercise.

There are many other natural ingredients that can be used for DIY fly sprays and they include: tea tree oil, garlic, cider vinegar, neem oil, aloe vera, lemon juice any many more.

In summary, choose your summer fly spray carefully, ignore marketing hype and check the ingredients and percentages yourself. Always patch test and remember there are also other ways to help your horse keep protected from flies this summer.

Enjoy the sunshine!

Jenny xxx