Hackberry "Sap" on Truck: It's Honeydew from Aphids/Scale

What's Falling

Not sap—honeydew from aphids or scale insects feeding on leaves/twigs. Sticky, sugar-rich; black sooty mold grows on it.

Active during growing season (spring–fall). Stops in winter when insects are dormant.

Honeydew + mold can etch clear coat if left long. Wash promptly.

Systemic soil drench: Imidacloprid (Bayer Advanced Tree & Shrub Insect Control) in spring. Best for tall trees—no spray drift.
Follow label for trunk diameter.
One application protects all season.

Foliar sprays (acephate, bifenthrin, etc.) but coverage on large hackberry is impractical.

Trees: Honeydew and Sooty Mold from Aphids on Street Trees: City Management; Oak Tree Dripping Sap? It's Honeydew from Aphids or Scale; Cottony Aphids on Young Sargent Crabapple: Identification and Control; Diagnosing and Treating Hackberry Tree Decline: Sooty Mold, Insects, and Squirrels; Littleleaf Linden Honeydew: Aphid/Scale Systemic Treatment; Maple Sap Dripping After Pruning: Normal or Aphids?; Sticky Sap Dripping from Oak: Aphids or Scale; Cottony Aphids on California Valley Oak; Crepe Myrtle Sooty Mold: Aphid Control Eliminates Black Fungus; Hackberry Honeydew: Aphid Excretion and Sooty Mold on Deck and Plants

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