Borer Holes and Gray Insects on Bradford Pear: Diagnosis and Action

Borer Holes and Gray Insects on Bradford Pear: Diagnosis and Action

Rows of 1/8-inch holes encircling a Bradford pear trunk, with gray insects emerging and blackened bark below, indicate borer activity. The black coating is sooty mold growing on insect honeydew. The insects may be the primary borers or secondary occupants of dead wood.

Steps to Take

1. Collect several insects in a vial and take them to your county Extension office for identification.
2. If they are borers (e.g., flatheaded appletree borer), treat the trunk with permethrin or a systemic like imidacloprid.
3. Assess canopy health: thinning or dieback suggests advanced infestation.
4. Improve tree vigor with watering and fertilization to slow decline.

Internal decay, once started, is progressive. Avoid future trunk wounds to prevent new entry points.