When you are busy working in the garden or hiking or generally enjoying the outdoors, few things are more irritating than the relentless buzzing and whirling of deer flies around your head. This is especially so because deer flies can inflict quite a painful bite. Unlike mosquitoes, who pierce the skin of their victim to secure their blood meal, deer flies use knifelike mouthparts to slice open the skin. They then feed on the blood pool that is created. Deer flies (genus Chyrysops)are members of the family Tabanidae. Their cousins, the horse flies (genus Tabanus) are the giants of the fly world, at over an inch long. There are 101 species of horse flies in North America. Black Horse flies (Tabanus atratus) are common, as are ‘greenheads’ (Tabanus americanus).
Horse fly season caught me off-guard this summer. One day there were no horse flies about and the next, they were present in swarms. The evidence of their arrival was clear when the horses came in for the evening. I was shocked at the attack poor Mousie had suffered!
Poor Mousie! I don’t know if it was her light colour that attracted the flies to her or just what, but she was in much worse shape than the others. I got a bucket of clean water and sponged down her chest. Her condition didn’t look too bad once the blood was cleaned off. The wounds of horse flies continue to ooze for a bit after the fly departs.
This called for a serious counterattack. I purchased some “Swat”, a fly repellant that can be applied directly to sensitive areas. it comes in bright pink, which allows you to see exactly where you have applied it. Mousie has an old scar on her chest that seems to attract flies, and they also attack an odd whorl of hair on the base of her neck.
The rest of her, I sprayed with a general purpose bug repellent. Horse flies like sunny places and the horses can also get some relief by standing in the shade of their shelter. It’s also common for swarms of smaller flies to cluster around horses’ eyes. These flies haven’t been too bad here to date, but you can get fly masks to protect the horse’s eyes if needed. It’s been a tough year for coping with biting insects. The combination of hot, humid days, followed by rainy spells, seems to have brought the bugs out in force. Fortunately, the horse fly numbers seem to be waning now.