Today was the first day this year that the deerflies were out in force. There doesn't seem to be any pattern to when they're around. Last year it was mid-May, the year before it was August. They appear for several weeks and then that's it for the year.
I tend to have a pretty strong reaction to deerfly bites. Nothing major, but the bites swell up and are maddeningly itchy for weeks on end. The first year was the worst, since my immune system was already on overload with all the new viruses, bacteria, fungi, and allergens that didn't exist in Arizona.
Last year I tried out deerfly patches, and they worked wonderfully. I guess there is a pretty small population on our farm, because after I had trapped about 20 of them they were no longer a problem. Those 20 just seem like hundreds because they are so aggresive!
So far I've trapped five, plus there was one that I smashed when it bit me on the leg. It's a little bit odd to walk around with a buzzing hat, but it's better than getting bitten. I highly recommend these patches for anyone dealing with deerflies.