Crabapple Tree with fungus

Asked August 7, 2017, 8:17 AM EDT

I have a large crabapple tree that has the second year of the leaves falling off and not many blossoms in the spring. It is a large tree. Also similar trees in my development look worse than mine, almost dead looking. Would the best economical solution be to take the tree down and plant one that is fungus resistant? I live in Upstate NY near Oneida Lake.
Thank you for your help!

Onondaga County New York

3 Responses

Thank you for your question about crabapple.

Crabapple species and cultivars have historically been susceptible to a wide range of diseases, especially apple scab fungus, cedar-apple rust, and fire blight. Many modern cultivars possess superior resistance to these diseases.

Following are ten highly recommended crabapples chosen from the Crablandia II research plot at Ohio State University's Secrest Arboretum, in Wooster, Ohio. See link here:

Hope this is helpful.

Thanks for your help but should I cut the tree down? If I don't have somebody treat it will it get worse?

The progress of the fungal disease will depend upon the type of fungus as well as the weather from year to year. Most fungal diseases are made worse by prolonged cold, wet springs like the one we just experienced. Apple and crabapple trees across the state are experiencing the same problem that you are seeing in your neighborhood and some tree fruit crops have been virtually wiped out by fungal disease in our state this year.

So, 2017 has been a particularly bad year but there is no way to predict what the weather related risk is for next year or the years that follow. Mild winters add to the level of disease vectors present in the spring as some are killed off by prolonged freeze.

There are some fungal diseases that may be controlled more easily with sprays than others. Cedar-Apple Rust, for instance, is very difficult to control without the removal of one of the host plants or a very consistent spraying routine.

While you are probably correct that what you are seeing is fungal disease, there are also nutritional and environmental problems that can have similar effects on a crabapple tree. Sapsuckers girdling thin barked apple and crabapple trees with tiny holes in the bark which restrict the uptake of water and nutrition is one example.

Your decision on whether to remove the tree depends upon your certainty that you have identified the problem correctly and your tolerance for rolling the dice on the weather from year to year. Most fungal diseases do not kill the tree unless they weaken it very severely, perhaps over years, by dramatic defoliation. If you are certain that you have a difficult to treat fungal disease and the tree is in a position that you value its appearance, replacing the tree with a resistant cultivar is worth considering.