Willow Tree Slime Flux: Bacterial Wetwood Diagnosis

White Substance on Willow: Slime Flux, Not Just Sap

A willow with white substance oozing from evenly spaced, patterned holes (¼ inch, rows) has yellow-bellied sapsucker damage complicated by slime flux (bacterial wetwood).

Sapsucker Signature

• Rows of ¼-inch holes, evenly spaced, often encircling trunk.
• Protected species—cannot be harmed.
• Feed on sap and insects attracted to it.

Slime Flux (Bacterial Wetwood)

• Bacteria enter sapsucker wounds (or other injuries).
• Anaerobic fermentation produces: gas (foam), alcohol (yeasty smell), organic acids.
• Ooze is "foamy," smells fermented, attracts insects (flies, wasps, bees).
• Not directly fatal but indicates internal bacterial colonization.

Management

• No cure for internal bacteria.
• Cosmetic cleaning: Spray off ooze with hose. 10% bleach solution (1:9) reduces odor/insects.
• Do NOT drill drain holes or fill cavities—worsens decay.
• Support tree health: Water during drought, mulch, avoid wounding.
• Seasonal pattern: Flux peaks spring/fall; often heals over years.

Borers vs. Sapsuckers

Borers make random holes with sawdust. Sapsuckers make patterned rows. Your description = sapsuckers + secondary slime flux.

Slime flux is common on oaks, elms, willows. It's messy but rarely kills the tree.