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Mulberry Tree with Borer Holes: Ambrosia Beetle Suspected

The Damage

A large mulberry in central California has ½″ holes in trunk and boughs. Gardener pollarded; holes remain.

Likely Pest

Redbay ambrosia beetle (or related Euwallacea spp.)—bores, carries symbiotic fungus that clogs vascular tissue, causing dieback. Same complex hits avocados in CA/FL.

Experimental Organic Option

Atomic Grow sprayed into holes and drenched—anecdotal success on Erythrina. Dilute 1 tsp/quart.

Standard Approach

Remove and destroy infested wood.
Monitor for new holes; consider trunk injection with labeled insecticide (requires pro).
Keep tree vigorous—water, fertilize, avoid wounds.

Plant Diseases: Mulberry Yellow Slime: Need Photo for Diagnosis; Fruitless Mulberry Decline Signs: Dead Branches and Loose Bark; Apple Tree Bark Separating from Trunk: Tree Dead or Dying—Check for Borers, Fire Blight, Contact Extension; Sugar Maple Lightning Strike and Lichens: Damage Assessment; Bark Shedding on Mature Mulberry: Stress, Lightning, or Decline?; Mulberry Borer Damage: Merit Insecticide and Fertilization; Removing a Fruitless Mulberry Tree and Preventing Regrowth; Mulberry Tree Height Reduction for Berry Access; Mulberry Tree Too Close to House: Transplant or Remove; Mulberry Tree: Birds Love It, Cars Hate It

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