Spots on tree

Asked June 6, 2019, 2:09 PM EDT

This tree had these spots last year- we were told to remove all the leaves and spray w a baking soda solution, but the spots returned again this year. What could the spots be and how to get rid of them? What kind of tree is this? We purchased this house two years ago.

Wayne County Michigan

4 Responses

Hello,
Thank you for your question.
This looks like pear rust, a fungus that grows during wet conditions in spring.
If you would take a picture of the trunk, and a picture of the whole tree, I may be able to ID it for you. Also, what color are the flowers and when did it bloom? Does it produce an edible fruit?
Once an ID is confirmed, I can give you some specifics for controling the disease.

Hi Laura- Photos attached.

The flowers were white, and I can’t remember when they bloomed. Maybe early May.

If it is pear rust, is there a remedy, preferably chemical free?

Hi Laura- Photos attached.

The flowers were white, and I can’t remember when they bloomed. Maybe early May.

If it is pear rust, is there a remedy, preferably chemical free?

Thank you for the pictures.

Yes this looks like ornamental pear tree. And this is some sort of rust on the leaves. European pear trellis rust fungus (Gymnosporangium sabine), has been a problem on ornamental pears in wet springs the last few years.

Here is what you can do to minimize rust disease-

Clean up leaves as soon as possible.

Remove nearby junipers or prune out spindle galls on them each year.( see figure 1a on page 5 of the Rust Diseases link, below).

Keep plants pruned to promote air circulation, so leaves dry as quickly as possible

Do not let sprinklers hit leaves

Use fungicide sprays early in wet springs and reapply according the label.

The leaves affected now cannot be ‘cured’. So, starting a spray program early next spring is important. Some Garden fungicides containing sulfur are listed as organic or “OMRI” Organic Materials Review Institute compliant. Use a fungicide listing rust as one of the diseases controlled, and listing pear or fruit trees. Thorough coverage is important, and repeat according to the label until wet weather subsides and the leaves are fully expanded. Remember to follow all label precautions, including protecting skin, eyes, nose, mouth when using any products.

Another option is to remove the tree and replace with an alternative that is disease resistant- dogwood, Japanese lilac tree, magnolia, disease resistant crab apples like

‘Red Jewel’ or ‘Sugar Tyme’

References - alternatives-

https://extension.psu.edu/theres-a-flowering-crabapple-for-that

https://mnhardy.umn.edu/varieties/trees/flowering-trees

Reference-see page 4 “Rust Diseases of Pears and Apples”

http://www.scaffolds.entomology.cornell.edu/2016/SCAFFOLDS-5-2-16.pdf

I hope this is helpful. Thanks, again.