Large Oak Dripping Sticky Sap: Aphid/Scale Control and Fertilization

25-year-old oak in SF Bay Area dripping sticky sap (second year). Two large dead limbs, bark splits. Owner asks about oak lifespan.

Cause: Sucking Insects (Aphids or Scale)

Honeydew from feeding insects. Control insects → sap stops.

Systemic insecticide: Bayer Advanced Tree & Shrub Insect Control (imidacloprid) applied to soil.
Fertilize: 10-10-10 at 1 lb per inch trunk diameter, now and spring. Before rain avoids watering.
Prune dead limbs.

Oaks live 100+ years. Fertilization boosts vigor against stress.

Trees: Pin Oak Twig Borer: Systemic Insecticide Solution; Large Oak Cavity with Standing Water: Drain & Foam, Don't Cement; Maple Honeydew on Property: Systemic Scale/Aphid Control; Water Oak Scale Infestation: Soil Drench Treatment; Oak Tree Slime Flux: Managing Sap Flow and Hornet Attraction; Oak "Sap" Problem: Actually Honeydew from Insects; Oak Tree Bee Swarms: Identifying Scale Insects and Honeydew; Twig Girdlers and Twig Pruners: Why Oak Twigs Are Falling; Diagnosing and Treating Honeydew Dripping from an Oak Tree; Aphid Honeydew on Red Oak: The Real Cause of "Sap" Dripping

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