Mulberry Yellow Slime: Need Photo for Diagnosis

Yellow Slime on Mulberry: Likely Bacterial Wetwood

Without a photo, the most probable cause of yellow slime + wet areas on fruitless mulberry is bacterial wetwood (slime flux)—fermentative bacteria (Enterobacter, Klebsiella, Clostridium) in heartwood producing gas pressure that forces foul-smelling liquid out through cracks.

Other Possibilities

• Yeast/fungal slime flux (less foul, more frothy)
• Insect frass + sap (borers, scale honeydew)
• Canker ooze (fungal/bacterial, usually targeted)

Diagnostic Questions (Send Photo)

1. Odor? (Fermented/beer = wetwood; sweet = insect honeydew; none = yeast)
2. Location? (Base = wetwood; branches = canker/insect)
3. Tree vigor? (Wetwood trees often vigorous)
4. Seasonality? (Wetwood peaks summer heat)

Management

Wetwood: No cure, rarely fatal. Drainage tubes sometimes installed but controversial. Maintain vigor. Avoid wounding.

Insect/canker: Targeted treatment after ID.

Action

Photo to Extension or arborist. Smell test. Monitor canopy. Don't panic—mulberries tolerate wetwood for decades.