PestHigh Severity

American Plum Borer

Euzophera semifuneralis (Lepidoptera: Pyralidae)

A cambium-feeding moth pest that bores into trees, creating reddish orange frass and gum pockets (gummosis). The major borer pest of stone fruits and ornamental trees, causing up to 33% decline in life span of cherry trees. Most damaging to scaffold crotches and graft unions of young trees.

Peak Season: Active throughout growing season when conditions allow entry
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American Plum Borer damage showing characteristic galleries and exit holes

Identification & Symptoms

What to Look For

Reddish orange frass visible on bark surface
Gum pockets (gummosis) from boring activity
Damage concentrated at scaffold crotches and graft unions
Potential scaffold breakage with wind or heavy crop loads
Horizontal feeding galleries under bark
Outer bark usually remains intact despite internal damage

Potential Damage

Larvae feed on cambium layer
Can eventually girdle trunk or scaffolds through horizontal feeding
Reduces tree lifespan significantly (up to 33% in cherry trees)
May cause scaffold breakage under stress
Spreads plant pathogens between trees
Contributes to enlargement of existing cankers

Lifecycle

Males and females are identical with 17-28mm wingspan. Eggs are oval, dirty white when laid, darkening to pink then deep red. Laid singly or in small masses near gummosis of bark wounds. Larvae develop in cambium layer, feeding horizontally and potentially girdling trunks or scaffolds.

Professional Treatment Approach

1

Prevent mechanical damage to bark

2

Seal wounds and bark damage promptly

3

Systemic insecticide injection for protection

4

Remove infested wood when possible

5

Maintain tree health to improve resistance

Recommended Mauget Products

Imicide

Professional-grade treatment specifically effective against american plum borer.

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Dinocide

Professional-grade treatment specifically effective against american plum borer.

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Need Professional Diagnosis?

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