Up on Lake Erie we have muffleheads and mayflies (aka Canadian soldiers).

On light-air days in mid-summer we are sometimes swarmed with muffleheads. They don't bite, but they land on everything and crawl around on you. They are strongly attracted to yellow, and I will never forget the year we were in the Sandusky Steeplechase on an all-yellow Hobie 18, and we were wearing yellow life jackets. The muffleheads LOVED us!

Mayflies are born in the water of the lake and when they are mature, they suddenly rise up out of the lake in great swarms. Rick got to experience this up close once when sailing in a distance race on a Corsair 31. It was a dark and windy night, and the boat was going very fast. When these mayflies started swarming up out of the lake, they were hitting the sailors in the face and smashing themselves on the boat, leaving soggy, slippery corpses everywhere. In a big mayfly year, they pile up in drifts in some lakefront towns.

At least both the muffleheads and the mayflies have a very short season, so they are not a common or ongoing problem.