Apple tree fungus? - Ask Extension
We have 4 apple trees that have branches that are turning brown and dying, but others that are thriving. The apples are growing and don't seem to be ...
Knowledgebase
Apple tree fungus? #803206
Asked July 26, 2022, 6:38 PM EDT
We have 4 apple trees that have branches that are turning brown and dying, but others that are thriving. The apples are growing and don't seem to be affected yet. We have a cherry tree that doesn't seem to be affected. Doing some research it seems we may have blossom fungus??? The trees are 10-15 years old and we'd love to keep them alive. Any thoughts or suggestions?
Isanti County Minnesota
Expert Response
The brown and dying branches have been damaged by fire blight.
Go here to learn about this disease and what to do about it:
https://extension.umn.edu/plant-diseases/fire-blight
https://blogs.cornell.edu/applevarietydatabase/fact-sheet-fire-blight/
Go here to learn about this disease and what to do about it:
https://extension.umn.edu/plant-diseases/fire-blight
https://blogs.cornell.edu/applevarietydatabase/fact-sheet-fire-blight/
Am I better off pruning it off now or waiting until winter?
Winter is the preferred time to remove branches affected by fire blight.
https://www.canr.msu.edu/news/prune_out_fire_blight_in_the_winter
Experts at Colorado State University say this about pruning in summer:
https://extension.colostate.edu/topic-areas/yard-garden/fire-blight-2-907/
https://www.canr.msu.edu/news/prune_out_fire_blight_in_the_winter
Experts at Colorado State University say this about pruning in summer:
Remove fire blight infected branches during summer only if the following conditions exist:
- Infections are in young, vigorous trees and the bacteria may girdle the main stem or main branches.
- Infections are in dwarfing trees on highly sensitive rootstocks, such as M.9 or M.26.
- The number of infections in older trees is limited and can easily be removed.
- It is a dry, sunny day when there is no chance of rain for 48 hours.
https://extension.colostate.edu/topic-areas/yard-garden/fire-blight-2-907/
