Black flies can be an annoying nuisance, particularly on sunny days. They are not common inside buildings or cars, but they can crawl around your body and bite you. Although the bite is usually shallow, black flies use their talons and tiny, serrated mandibles to scrape the skin and suck blood. This can cause a welt and can be very painful. The most common areas where black flies bite are your ankles and behind your ears.
If you’re concerned about black flies, you can try spraying your nest box or the outside of it with a repellent, such as Flys Away II. This insecticide is effective for killing black flies, and it also has low residual activity. BRAW recommends spraying the box daily when blackflies are active. You can also spray the chicks with the same repellent.
Another option is to apply Diatomaceous Earth. This substance contains ground diatom mantels and is highly abrasive to many arthropods, including Blackfly. Its sharp, tooth-like edges cause discomfort to the pest and may weaken its health. It can be applied directly to plants, or you can sprinkle a thin layer over foliage.
Black flies prefer moist areas, and they will swarm in places with high humidity. If you are prone to black flies, make sure you stay away from bodies of water.