How to know if Ash Borers are Attacking Your Trees

​The symptoms an ash tree shows when it is infested with ash borer are similar to symptoms caused by other ash pests or diseases in Connecticut.  For example, crown dieback can occur due to ash borer damage, but can also be the result of drought stress, soil compaction or verticillium wilt, just to name a few.  Therefore, it is important to look for a combination of at least two symptoms or signs when trying to figure out if ash borer is in your ash tree.

Symptoms

Crown dieback: Dieback of the upper and outer crown begins after multiple years of ash borer larval feeding. Trees start to show dead branches throughout the canopy, beginning at the top. Larval feeding disrupts nutrient and water flow to the upper canopy, resulting in leaf loss. Leaves at the top of the tree may be thin and discolored.

Epicormic Sprouting: When trees are stressed or sick, they will try to grow new branches and leaves wherever they still can. Trees may have new growth at the base of the tree and on the trunk, often just below where the larvae are feeding.

Bark splits: Vertical splits in the bark are caused due to callus tissue that develops around larval galleries. Larval galleries can often be seen beneath bark splits.

Woodpecker feeding: Woodpeckers eat ash borer larvae that are under the bark. This usually happens higher in the tree where the ash borer prefers to attack first. If there are large numbers of larvae under the bark the woodpecker damage can make it look like strips of bark have been pulled off of the tree. This is called "flecking."

Signs

D-shaped emergence holes: As adults emerge from under the bark they create a D-shaped emergence hole that is about 1/8 inch in diameter.

S-shaped larval galleries: As larvae feed under the bark they wind back and forth, creating galleries that are packed with frass (larva poop) and sawdust and follow a serpentine pattern.

Larvae: Larvae are cream-colored, slightly flattened (dorso-ventrally) and have pincher-like appendages (urogomphi) at the end of their abdomen. By the time larvae are done growing they are 1 1/2 inches long. Larvae are found feeding beneath the bark. 

Adults: Adult beetles are metallic green and about the size of one grain of cooked rice (3/8 - 1/2 inch long and 1/16 inch wide). Adults are flat on the back and rounded on their underside.
 
If you think you may have ash borer in your ash tree call a professional like Cutting Edge Tree Care Specialists!