Fort Collins Tree Care Fort Collins Tree Care  
Dedicated to Tree Preservation
in the Urban Forest
 
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Fort Collins Tree Care Fort Collins Tree Care
Click for a FREE estimate
or call 970.484.3084
Dedicated to Tree Preservation in the Urban Forest
Fort Collins Tree Care Fort Collins Tree Care
Click for a free Estimate or call 970.484.3084
Dedicated to Tree Preservation in the Urban Forest
Fort Collins Tree Care
or call 970.484.3084

What is ink spot?

Ink spot is caused by the fungus Ciborinia whetzelii. It mainly attacks aspen, but also poplars and cottonwoods. It causes most damage to small trees and the lower leaves of larger trees. Severe infections make a tree more susceptible to other diseases, insects, frost damage and may make the tree look bad, but it rarely causes long term damage or kills a tree.

Ink Spot Steven Katovich, USDA Forest Service, Bugwood.org

How to identify ink spot

Look for large numbers of dead leaves, and raised black "ink spots" about 1/4" across on dead, brown leaves. In late summer these spots will drop out of the leaves leaving leaves with "shot holes" on the tree. The Ciborinia whetzelii fungus causes reddish brown spots on the leaves a few weeks after infection. Often the entire leaf will turn brown before the "ink spots" appear.

Ink Spot William Jacobi, Colorado State University, Bugwood.org

Life cycle of ink spot

The Ciborinia whetzelii fungus overwinters in the leaf debris on the ground, as a mass of fungal material. Wet spring weather causes the fungus to create fruiting bodies that release spores. These spores are carried by wind and rain to the leaves. 2-3 weeks after infection brown spots appear, expanding until they cover the entire leaf. 2-3 weeks after brown spots appear, 1-4 black "ink spots" appear on each leaf. Infected leaves die in the summer, but may stay on the tree until fall. In late summer the "ink spots" drop from the leaves to the ground where the fungus will overwinter.

Ink Spot William Jacobi, Colorado State University, Bugwood.org

How to control ink spot

Pick up and remove leaves and debris around the base of trees after the leaves drop in the fall to prevent reinfecting trees in the spring. Greater spacing between trees makes it harder for ink spot to spread to new trees. Prune for good air flow to help leaves dry out, and adjust sprinklers so they don't get water on the leaves.

Fungicides can prevent infection if applied before symptoms appear, but will not cure already infected leaves.

 

Ink Spot on aspen William Jacobi, Colorado State University, Bugwood.org

 
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301 E. Douglas Road
Fort Collins, CO 80524
970.484.3084
Fort Collins Tree Care Inc.
301 E. Douglas Road
Fort Collins, CO 80524
970.484.3084
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