What Is It?
The cottony psyllid (Psyllopsisdiscrepans) belong to the family of insects sometimes called jumping plantlice.
Attacks by this psyllid on black ash trees can be very noticeable. Natural control of this insect in our area seems to be largely lacking at this time.
What's the Problem?
These cottony psyllids attack black and Manchurian ash, but not green ash. These insects suck sap from the leaflets. This feeding causes ash leaflets to become shriveled and discoloured. The leaflets curl under from the sides to enclose the psyllids and a white, cottony material they produce.