Apiosporina morbosa (Schwein. : Fr.) Arx 1954

Black knot fungus

About plant names...

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.

Online References:

Wikipedia

Hort.extension.wisc.edu

References:

Russo, Ron, Field Guide to Plant Galls of California and Other Western States, University of California Press, 2006, p. 280

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)

Apiosporina morbosa description by Thomas H. Kent, last updated 5 Sep 2023.

© FloraFinder.org. All rights reserved.

Looks like the infected tree is wild cherry. · 8/15/2015 · Grafton Notch State Park, Newry, Maine
≈ 8 × 5" (19 × 13 cm)

Looks like the infected tree is wild cherry. · 8/15/2015 · Grafton Notch State Park, Newry, Maine
≈ 6 × 4" (16 × 10 cm)

4/27/2023 · Mitchell Field, Harpswell, Maine

10/25/2009 · Nashua River Rail Trail, Nashua, New Hamp­shire
≈ 11 × 7" (27 × 18 cm)

10/25/2009 · Nashua River Rail Trail, Nashua, New Hamp­shire
≈ 4 × 4½" (10 × 11 cm)