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Cottony Maple Scale on Elm and Maple: Identification and Control

White Marshmallow-Like Sacs on Trees? Cottony Maple Scale

These are egg sacs of cottony maple scale (Pulvinaria innumerabilis), common on silver/red maples and sometimes elms. Heavy infestations cause honeydew, sooty mold, and branch dieback on stressed trees.

Management

Improve tree vigor (water, fertilize, reduce compaction).
Systemic imidacloprid (Bayer Advanced) soil drench.
If reachable, spray crawlers with Orthene (acephate) at proper timing.
Avoid broad-spectrum sprays that kill natural predators (lady beetles).

Plant Diseases: Japanese Maple Scale Infestation: Simple WD-40 and Oil Treatment; Elm Trees with Holes in Leaves: Elm Leaf Beetle Damage; Sugar Maple Yellow Fungus and Black Leaves: Disease Overview; Maple Gall Mites: Cosmetic, No Treatment Needed; Maple Crown Gall: Bacterial Disease with Organic Treatment Option; Elm Finger Gall vs. Maple Bladder Gall: Identification and Management; Hypoxylon Canker and Root Stress Killing Mature Trees in Wet Soil; Cottony Maple Scale: Systemic Imidacloprid Best for Large Trees; Transplanting Wild Maple and Elm Seedlings: Direct Plant Beats Pots; Maple Tree Decline: Moss, Bark Loss, and Mushrooms Signal Aging, Not Just Disease

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