Ash trees are often found in open, sunny sites and are most susceptible to a bug attack, especially newly transplanted trees, as the insects prefer feeding on young tissue. When attacked, the leaves appear distorted, burned and stippled at an obvious premature time frame. The threat of egg-laying punctures may also result in diseases entering the plant.
There are two methods of control; organic and chemical.
The organic method requires a vigorous growing condition, supplying adequate moisture and fertilizer, helping the tree withstand damage. Although, adult bugs are often found returning to the tree.
There’s also the chemical method which requires the use of insecticides. First application is recommended in mid-May when the leaves are expanding; however it’s only necessary when insects are visible or when damages first appear. Insecticidal soaps and Pyrellin are most accepted among organic growers, and while large trees are difficult to spray, they’re less likely to require treatment.
If treatment is necessary, consider consulting a professional tree care service for assistance.