Shoo, fly! Catnip oil repels bloodsucking flies

Junwei Zhu and colleagues note that stable flies not only inflict painful bites, but also transmit multiple diseases. Cattle harried by these bloodsuckers may produce less meat and milk, have trouble reproducing, and develop diseases that can be fatal. All traditional methods for controlling stable flies -- even heavy applications of powerful insecticides -- have proven less than effective. The scientists thus turned to catnip oil, already known to repel more than a dozen families of insects, including house flies, mosquitoes and cockroaches.

They made pellets of catnip oil, soy, and paraffin wax, and spread them in a cattle feedlot. Within minutes, the pellets shooed the flies away, with the repellent action lasting for about three hours. Pellets without catnip oil, in contrast, had no effect. The scientists now are working on making the repellent action last longer, which they say is the key to putting catnip to use in protecting livestock both in feedlots and pastures.