WSU Extension


Ornamental Plum
Armillaria root rot 
Brown rot 
Crown gall 
Cytospora canker 
Plum pockets 
Shothole (Coryneum blight) 
Silver leaf 
Hop aphid 
Leaf curl plum aphid 
Peachtree borer 
Pear slug 

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Caption: Peachtree borer and damage at base of tree
Photo by: K. Grey
Ornamental Plum : Peachtree borer
(revision date: 3/10/2017)

The western peachtree borer is the larvae of a clear-winged moth. Adult moths are blue-black, about 1" across, have mostly transparent wings, and appear somewhat wasp-like. They are attracted to bark injuries. The larvae are white to yellowish with brown heads and often mine around the roots, in the trunk at ground level, or higher on the trunk. Mined trees often have gumming (sap leakage) and large amounts of a sawdust-like material present at the entrance holes. Mining can weaken and kill large branches and entire trees by girdling them.
Management Options

Non-Chemical Management
  • Avoid injuries to trees, particularly to the trunk and crown areas.
  • Prune during late winter to early spring, so wounds can heal before adult female moths are laying eggs.
  • Carefully remove individual larvae with the tip of a pocketknife. Try to avoid further damage to the tree.
  • Maintain vigorous, healthy trees.
Select non-chemical management options as your first choice!

Chemical Management

Esfenvalerate is toxic to bees. Do not apply products containing esfenvalerate on or near blooming plants. To minimize risk to bees, apply in the evening after bees have stopped foraging for the day. Apply generally in late spring or when adults are active. Adult flight is usually from late June through September. Apply product to trunk at base above soil line.

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.
  • Monterey Bug Buster II
    Active ingredient: esfenvalerate  |  EPA reg no: 1021-1778-54705
  • This list may not include all products registered for this use.

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Caption: Peachtree borer and damage at base of tree
Photo by: K. Grey