Can you make bug spray with skin so soft for horses?

[1] The horse-friendliest sprays to control bugs tend to use one of two sets of active ingredients: the botanicals, and the oils. [2] The botanicals are made from plants. They're ka cypermethrin, permethrin, and pyrethrin. [3] The oils tend to be made from lemongrass, geranium, and citronellagrass. [4] Horses have sensitive skin. So there's no guarantee that even the preceding won't irritate. [5] So insecticidal soap, which can be bought as such, or made in the home from dish soap and water, is a third option.