Meet Blue Ash Aphid
These lovely warm late fall days have us all getting outdoors. Has any one noticed the little tiny flying blueish insects in the sunlight? If not, take a bike ride, you'll likely notice them when you're picking them out of your teeth and eyes. The Blue Ash Aphid is in the middle of an incredible part of its lifecycle but we generally only notice them as an annoyance to our outdoor activities.
They don't bite humans, or any other animals. They do feed on trees though, specifically on Ash trees and lilacs. Right now, during those last hazy warm afternoons, the swarms of fuzzy little flies are mating. Here's the interesting thing. They only mate for a few days a year but they are all born as females, capable of laying eggs without males. However, come Fall, some develop into males. These insects are also wingless all summer, feeding on leaves. They develop wings just for the fall mating season. There is also some research that states these insects live in the roots of fir trees all winter, feeding on the roots. Their life cycle is complicated!
These insects pose no threat to you or your plants aside from some discoloration during their feeding on Ash trees during the summer. They do pose a serious threat to young nursery grown ash but wild trees seem quite capable of withstanding their feeding. There's no need to use pesticides if you do find them on your plants, simply spray them off with water. Blue Ash aphids are so delicate when they are wingless that simple water from the hose will destroy them.
For those couple of warm late/fall days, we get to enjoy their fairly like appearance in the sun. They have been called 'fairy aphids', compared to snowflakes, and likened to haunts in the late October dusk. The certainley appear ethereal as they swarm above meadows and along forest edges. Then, once the weather cools into freezing, we'll have to wait until next fall to see them.