Weeping Oak Sap: Aphid Honeydew, Not Tree Sap

Large oak in S. Manitoba weeping sap from leaves for first time in 13 years. Sticky? Owner fears serious condition.

Check Stickiness

If sticky = aphid honeydew (excrement). Aphids suck leaf juices, secrete sugar-rich liquid. Sooty mold often follows (black leaves).

Treatment (If Needed)

• Foliar spray: acephate, bifenthrin, malathion, etc. (contact).
• Systemic soil drench: imidacloprid (Bayer Advanced) or acephate (Orthene).
• Large trees may need professional sprayer.

Impact

Aphids don't kill mature oaks. Honeydew is nuisance on surfaces below.

If not sticky, could be bacterial wetwood (slime flux)—different management.