When sharing the recipe for my tried-and-true natural fly repellent for horses, I occasionally get a comment about how citronella (one of the essential oils in the recipe) is rumored to attract killer bees.
I have used this blend since the mid-’90s and have never noticed it attracting bees of any kind. Twice my horses have lived on properties where beekeepers kept honeybee hives. And we’ve been in both Arizona and Colorado, states where you do hear about the Africanized bees causing occasional problems.
I decided to do a bit of web surfing to find out whether there has been any research done on the topic and, behold, I found a 2003 study done right here in Tucson using both human and horse insect repellents.
Researchers at the Carl Hayden Bee Research Center found that Pyranha horse fly repellent, which contains citronella, did not seem to attract the bees while Repel-X, which has none of the oil, for some reason did cause bees to attack. (The study is a few years old, so the product could have been re-formulated since then.)
After drilling down pretty deep looking for any credible sources that indicated a connection between killer bee attacks and citronella, I can report that I found none.
It’s actually lemongrass essential oil you might need to be careful with because it mimics bee pheremones.
So I feel completely confident using citronella in my fly spray blend. I have found it the most effective ingredient when I’ve lived where mosquitoes and gnats were the main problem (irrigated pastures in Colorado farm country.)
A note of caution: Please be sure your citronella is the actual pure essential oil. Do not use any kind of citronella-scented petroleum product designed to be burned in those outdoor tiki torches or any kind of oil lamp. Apparently some people have tried that with predictably bad results.
While 100-percent citronella oil is generally safe for both humans and horses, realize some of us and our horses are overly sensitive to certain substances. So always use your citronella diluted – never neat – and be sure to spot test your fly repellent blend on a small area before you spray yourself or your horse all over.