Peach Tree Borer Fatality in Mature Plum Tree

A 20-year-old Victoria plum tree showing sudden leaf loss, minimal flowering, and gummy amber exudate (gummosis) on the trunk has succumbed to peach tree borer (Synanthedon exitiosa) — a fatal pest of stone fruits.

Understanding the Damage

Peach tree borer larvae spend 75% of their life cycle tunneling beneath bark, destroying the cambium and phloem that transport water and nutrients. The gummosis is the tree's desperate attempt to seal exit holes where adult borers emerged.

Why Detection Fails

• Borers enter near soil line, hidden by mulch or vegetation.
• External symptoms appear only after extensive internal damage.
• No effective preventive sprays exist for home gardeners.

Management Reality

With complete defoliation and active gummosis on the main trunk, the vascular system is destroyed. The tree cannot recover. Removal is necessary to prevent borer spread to nearby stone fruits (peaches, cherries, other plums).

Replacement Strategy

• Remove entire tree, including stump and major roots.
• Do not replant stone fruits in the same location.
• Consider borer-resistant alternatives or non-host species.
• Monitor nearby stone fruits for early signs of infestation.

While disappointing, prompt removal protects your remaining fruit trees from this destructive pest.