black goo, name coined in 1995 by American viticulturist Lucie Morton to describe the symptoms of black spots and tarry ooze in xylem vessels produced by Phaeomoniella chlamydospora and Phaeoacremonium species, fungi that cause decline in young vines. It is now known as petri disease. The same symptoms and fungi are found in older vines suffering from esca. See also black xylem decline.
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