Borers - Trees and Shrubs

clearwing borer gummosis on cherry
Photo:  Gummosis from peach tree borer infestation.

Back to Common Problems - Trees and Shrubs

Many different borers attack shade trees. They may be beetles or caterpillars. Beetle borers include bark beetles, long horned beetles (locust borer) or round headed borers (red headed ash borer larva) and metallic wood borers (bronze birch borer or flatheaded appletree borer) or flatheaded borers. Beetle borers are generally stress pests and usually only attack stressed trees. Symptoms include branch dieback and exit holes. Healthy trees are usually not attacked. The best control for beetle borers is to keep trees healthy and well watered. No sprays are effective for control.

Clearwing borers are the larvae or caterpillars of clearwing moths. The moths resemble wasps in appearance. Common examples are peach tree, lesser peach tree, dogwood, lilac, and ash tree borer. Larvae of these borers are creamy colored with brown heads. Signs of damage include holes in the bark, reddish frass in bark crevices or around the bottom of the tree and branch dieback. In the case of peach tree and lesser peach tree borer in flowering cherries, gummosis may be present. 

Management: To help prevent borers, especially in Prunus, keep mulch away from the base of the tree. Keep trees well watered during dry periods. Avoid wounding the trees, especially with lawn mowers and string trimmers. Beneficial nematodes may be used to control these caterpillar borers as long as there is no gummosis. Follow package directions and spray in the evening.

Photo Gallery

peach tree borer damage peach tree borer adult
Signs of damage from clearwing borers (peach tree borer) include holes in the bark, reddish frass in bark crevices or around the bottom of the tree and branch dieback
Adult peach tree borer.
peach tree borer larva ash borer adult
Peach tree borer larva..all clearwing borer larvae look very similar.
Ash tree borer.
bronze birch borer with exit hole bronze birch borer
Bronze birch borer and "D" shaped exit hole.
Bronze birch borer larvae with frass
bronze birch borer hole Carpenter worm larva and damage.
Bronze birch borer hole.
Carpenterworm caterpillar and damage.
dogwood borer adult flathead apple borer
Dogwood borer and pupal case.
Flatheaded appletree borer.
locust borer
Locust borer.
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