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Plum Tree Soft Bark Bumps: Scale Insect Infestation

Identifying the Bumps

Small, soft, easily scraped bumps on 5-year-old plum trunk/branches that leave bark depressions are scale insects—not a disease. Oval, stationary, suck sap; heavy infestations can kill branches or entire tree.

Urgent Treatment Needed

Treatment depends on fruit edibility:

Edible fruit: Horticultural oil (dormant) or insecticidal soap/growth regulator (growing season)—check pre-harvest intervals.
Ornamental only: Imidacloprid soil drench (systemic, 12-month control).

Why Act Now

Scales reproduce rapidly. Each female lays hundreds of eggs. Crawlers spread to new growth. Early intervention prevents dieback and sooty mold buildup.

Contact local extension for product recommendations matching your harvest intentions.

Plant Diseases: Scale Insect Infestation on Star Magnolia: Identification and Control; Plum Tree Leaf Curl and Eggs: Beneficial vs. Pest Identification; Gummosis on Ornamental Plum: Insect Wounds and Sap Flow; Plum Tree with Raised Bark: Black Knot Disease; Plum Tree Loose Bark with Magenta Spores: Complex Diagnosis Needed; Plum Pocket Disease: Remove Fruit, Fungicide Next Year; Debunking 'Insivianvaculosis': What a Hollow Tree Really Means for Tree Health; Plum Tree Pruning for Fruit Production; Maple Leaf Galls: Harmless Cosmetic Issue; Plum Tree Leaf Spot and Fruit Drop in New Zealand

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