Borers: Identification, Prevention, and Chemical Control

Beetle larvae bore into trees or tunnel under bark, girdling branches and trunks, cutting off water/nutrients. Early signs: wilting/yellowing on a single branch; small holes with sawdust, frass, or sap. Some enter below soil line—evidence only at base. Vulnerable: fruit/nut trees, ash, dogwood, lilac, cane berries—especially if stressed.

Prevention

• Keep trees healthy with proper fertilizing/watering; extra attention during drought.
• Avoid bark damage.
• Prune in midsummer so wounds heal before spring larvae emerge.
• Cut and burn infected branches.

Chemical Control

Spray when adult beetles lay eggs in summer. Use chlorpyrifos.