Picture of the Week

September 21, 2020

Sooty Mold on Beech

Gail Ruhl, Plant Disease Diagnostician


The sponge-like growth on this branch and leaf collected from a beech tree

is an unusual type of sooty mold. Sooty molds are entirely superficial

saprophytes that get their nourishment from honeydew-like secretions from

insects such as aphids, soft scale, and mealy bugs.  The beech tree was

infested with a woolly aphid species and thus this specific sooty mold

fungus, known as Scorias spongiosa, is feeding on the honey dew excrement

from the woolly aphid.

Click image to enlarge


sooty mold on beech

Sooty Mold on Beech

Photo by Bruce Watt, University of Maine


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