WSU Extension


Armillaria root rot 
Bacterial canker 
Black knot 
Brown rot blossom blight and fruit rot 
Crown gall 
Cytospora canker 
Dead bud 
Gumming (Gummosis) 
Leaf spot 
Little cherry 
Mottle leaf 
Necrotic rusty mottle 
Powdery mildew 
Prunus necrotic ringspot 
Shothole (Coryneum blight) 
Verticillium wilt 
Witches'-broom (Cherry leaf curl) 
Apple-and-thorn skeletonizer 
Black cherry aphid 
Brown marmorated stink bug 
Cherry bark tortrix 
Cherry fruit fly 
Cutworms and armyworms 
Peachtree borer 
Pear slug (Cherry slug) 
San Jose scale 
Shothole borer 
Spider mites 
Spotted wing Drosophila (SWD) 

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Caption: Black knot
Photo by: R. Byther
Cherry : Black knot
(revision date: 6/5/2018)

Black knot is a fungal disease that infects cherry and plum. Early infections of twigs are elongated olive-green, corky knots. They turn black and hard as they mature. Every year they expand lengthwise. It is possible for the fungus to stunt and kill limbs as it grows around the twig or branch.
Management Options

Non-Chemical Management
  • Remove knots, cutting 3 inches below the knot. Burn or bury infected debris.
Select non-chemical management options as your first choice!

Chemical Management

None recommended.


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Caption: Black knot
Photo by: R. Byther