I get the Pyranha 1-10 HPS instead – it’s .30% pyrethrins, so if you mix it 1:2 you get back down to the 0.10% that is usually in their ‘wipe & spray’.
This: https://www.valleyvet.com/ct_detail…a%201-10%20hps
(Which is $55/gallon so maybe that’s what someone was thinking of… this is the best price I found when I did the calculations based on the active ingredients, but it was a few years ago.)
I swear I need to start keeping a fly journal from year to year. Because every summer, I find myself saying things like, “the bugs are so bad this year!” or “this fly spray worked great last year but isn’t doing anything now!” I am truly curious how much is accurate perception v. blissful amnesia.
But the flies do seem particularly bad this year. They laugh at a 1:4 dilution of Repelx-- I might as well be spraying water on the horses. My other “go to” brands aren’t doing much better (Endure, Ultrashield, Equisect, etc). Ecovet seems to work well while it lasts for the black barn flies, but doesn’t to help with the bigger horse flies that chase us during our rides. I picked up some Equiderma Neem & Aloe Spray this morning and it smells wonderful; I couldn’t tell how well it was working, though.
Just to address the questions on claims on labels and testing. Any fly spray that is making an insecticide (“kills”) claim must be registered with the EPA. The EPA requires safety and efficacy data for every product that is registered. Additionally, all of the language that you see on an EPA registered fly spray label has to be approved by the EPA as part of the registration of the product. A fly spray manufacturer cannot put any claims or any language on their labels, nor their advertising, that cannot be proven and has not been approved by the EPA. As you all noted, fly conditions can vary dramatically from area to area and horse to horse. This is why the data submitted as proof of safety and efficacy for the product is done in laboratory conditions. The laboratory provides the controlled environments necessary for proper testing. If a manufacturer is using a formula that they have purchased, they can rely on the safety and efficacy testing done by the company they purchased the formula from. If the formula is unique to the manufacturer, or if that manufacturer wants to make additional claims, they must conduct their own tests that meet EPA standards in order to substantiate their claims and also prove safety.
“Natural” products are rarely (I have never seen one) registered with the EPA. Rather they are claiming a 25(b) exemption from EPA registration by claiming that they use natural oils known to repel insects such as citronella, geraniol, eucalyptus, thyme, cedar oil, lemongrass, rosemary oil, and clove oil. Natural fly sprays do not contain insecticides and so they will not kill insects. Natural fly sprays only repel insects. Because of this, natural fly sprays will not be effective at reducing the insect population around your barn. The ingredients in natural fly sprays also breakdown more quickly than their chemical counterparts and so they must be reapplied often.
Additional general information:
Actives are the ingredients that have insecticide (killing) and repellent power. Many of the most commonly used actives have both insecticide and repellent characteristics. There are two forms of actives, namely natural and synthetic. The most common actives are pyrethrins, permethrin, resmethrin, tetramethrin, and cypermethrin. More recently, picaridin has come on the market for use as a combined horse and human insect repellant spray.
Pyrethrins are natural and are extracted from certain types of chrysanthemums. They provide very quick knockdown – in other words, they kill the insects quickly. However, pyrethrins are broken down rapidly by sunlight, so synergists are often added to protect and extend the effectiveness of the formula.
Pyrethroids are synthetic forms of pyrethrins. The most common pyrethroids are permethrin, cypermethrin, tetramethrin, and resmethrin. Pyrethroids are not as easily broken down by sunlight, so their effectiveness can last for several days. Both pyrethrins and pyrethroids have a long track record for effectiveness and animal safety on horses.
Many of the actives listed above work with a synergist. Synergists are chemical agents used in conjunction with the actives to enhance killing power and provide longer-lasting protection. The most commonly used synergists are Piperonyl Butoxide (PBO), Butoxypolypropylene Glycol, and N-Octyl Bicycloheptene Dicarboximide (MGK 264).
Piperonyl Butoxide kills by attacking the fly’s central nervous system and provides a quick knockdown. It kills on contact when used with pyrethrin. Butoxypolypropolene Glycol has residual effects, acts as a repellent and is water repellent. N-Octyl Bicycloheptene Dicarboximide is both a mosquito repellent and a synergist. It helps prevent the insect’s body from producing a detoxifying enzyme, therefore preventing insecticide degradation.
When comparing fly sprays, it’s important to look beyond the price tag and focus instead on the list of the active ingredients and the levels of those ingredients included in the formula. Let’s say you have brand A and brand B. You look at the active ingredients and their percentages and see that brand A contains 0.10% permethrin and brand B contains 0.50% permethrin. That means there is 5 times more of the active ingredient in brand B. It’s easy to be disappointed by brands with very low levels of actives and therefore a lower price.
Another point of difference in fly sprays is whether they’re water-based or oil-based. There are advantages and disadvantages to both. Water-based fly sprays are non-toxic and non-irritating to the horse’s skin and won’t attract dirt or dust. However, water-based sprays should also include synergists in the formula to keep them from breaking down in environmental conditions (sunlight, rain, sweat, etc.). Oil-based fly sprays quickly stick to the hair coat and provide rapid knockdown of insects by suffocating them when sprayed. However, due to the nature of oil, oil-based fly sprays will attract dirt and dust. In addition, oil-based fly sprays can irritate the skin of sensitive horses and some horses are prone to burning if they are sprayed with an oil-based product and then turned out in the sun. It’s not always easy to determine if a fly spray uses a water or an oil base. The easiest way to tell is to look at the bottom of active ingredient listing. If you see the statement, “Contains Petroleum Distillate” then you know the product is oil-based.
Thank you! That’s an excellent summary of fly spray facts, and supports my comment that most fly spray are using the same ingredients, so if one permethrin spray isn’t working on your flies, buying a similar one from a different brand is likely not going to be any better.
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