Brown spots, curling leaves, sticky sap on 14-year-old aspens in Oregon = aphid infestation. Aphids feed on leaf undersides, causing curl and spots; honeydew drips below.
Apply Bayer Advanced Tree & Shrub Insect Control (imidacloprid) as soil drench. Roots translocate to 3–4 story canopy—kills aphids feeding on leaves. Takes 2–3 weeks to reach top.
Product: Bayer Advanced Insect Control
Mature aspens too tall for effective coverage. Soil drench is the only practical method. Honeydew stops; sooty mold weathers off; tree recovers.
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