Sooty Canker (Hendersonula toruloidea)
in the Low Desert

HOST:

Occurs on many types of woody plants, most common on mulberry (because of heavy pruning), but also on carob, elm, citrus, etc.

SYMPTOMS:

Foliage of affect limbs is sparse and leaves can be small. Dry, thin bark will crack and split to reveal black, powdery spores. Branches die back to the canker. Can occur anywhere on the tree.

CAUSE:

This fungus can only infect its many hosts via a wound. Pruning often opens the door, either directly through the pruning cuts, or indirectly by exposing the stems to sun scald. Sapsuckers or rubbing branches in the canopy can also provide entryway.

MANAGEMENT:

Prune infected branches at least 4 inches below the canker (12 inches is best). Apply a broad spectrum fungicide to the wound. Prune small limbs as symptoms appear, but wait to prune large branches until winter, to prevent further sun scald injury. This fungus can be spread on tools, so clean them with 10% bleach solution or rubbing alcohol after each cut.

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