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Slime Flux

Slime Flux, Bacterial wetwood

A close up of an Clematis slime flux infection
Slime flux is a bacterial disease that affects a range of host tree species including oak, ash, maple, poplar and elm trees. Bacteria targets the sap that is released from wounds in the plant surface. Wounds may be caused by insect damage, pruning, poor branching or the natural splitting and cracking of the bark.


Infected sap is dark and stains bark
Eventually sap takes on a foamy appearance and smells unpleasent.
Slime-infected sap becomes toxic to bark and degrades tree
Fermenting slime-sap mixture also attracts insect pests such as flies, ants and maggots.


There is no cure, however disinfecting the wound and wiping off excess sap is highly advised. With continuous monitoring and repeated treatments such as this, tree death can be avoided.

Affected plants


Ulmus spp.

Poplar Tree

Populus spp.


Acer spp.


Fraxinus spp.


Quercus spp.

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