Black knot fungus is a plant pathogen that once severely impacted Prunus
species, such as plum
and cherry trees. It is native to North America.
Identification: This disturbing looking fungus creates
a black, rough, uneven swelling. They are hard and dry to the touch, like charcoal briquets.
Although it is well-controlled in most of today’s orchards,
I see it quite commonly on wild cherry in New England. The knotty swellings can be ⅞-12" (2.5-30 cm)
in size, wrapping around branches, and they eventually kill the tree.
Looks like the infected tree is wild cherry. · 8/15/2015 · Grafton Notch State Park, Newry, Maine ≈ 6 × 8" (14 × 20 cm)
10/25/2009 · Nashua River Rail Trail, Nashua, New Hampshire ≈ 7 × 4½" (17 × 11 cm)
11/3/2011 · Pearl Hill State Park, Townsend, Massachusetts ≈ 13 × 20" (33 × 50 cm)
Roughly 75 people in North America are poisoned each year by mushrooms, often from eating a poisonous species that resembles an edible species. Though deaths are rare, there is no cure short of a liver transplant for severe poisoning. Don't eat any mushroom unless you are absolutely certain of its identity! Please don't trust the identifications on this site. We aren't mushroom experts and we haven't focused on safely identifying edible species.
Dibotryon morbosum (Schwein.:Fr.)Theiss.&Syd.1915
Sphaeria morbosa Schwein.:Fr.1822
Botryosphaeria morbosa (Schwein.:Fr.)Sorauer1921
Cucurbitaria morbosa (Schwein.:Fr.)Ellis1881
Otthia morbosa (Schwein.:Fr.)Ellis&Everh.1892
Plowrightia morbosa (Schwein.:Fr.)Sacc.1883
Apiosporina morbosa description by Thomas H. Kent, last updated 5 Sep 2023.