A 2019 research study by Elizabeth Tuorinsky and Erika Machtinger published in the Journal of Economic Entomology confirms that, in head-to-head comparisons with other fly spray products, Ecovet is the most effective at inhibiting flies AND Ecovet lasts the longest.
The study included a wide range of commercially available repellents, including those marketed as natural and those with synthetic pyrethroids as active ingredients.
"The natural products performed as well as or better than the synthetic products at all dilutions and times. Ecovet in particular retained over 75% inhibition of flies for >1 d at the 100 and 50% concentrations."
See the findings for yourself by clicking on the report below: