Apple trees with disease - Ask Extension
Hi,
We bought two apple trees(McIntosh and Sweet 16) with flowers on them from Fleet Farm 2 weeks ago. Now, I realize the leaves (maybe 5-10 of each...
Knowledgebase
Apple trees with disease #870340
Asked May 27, 2024, 10:15 PM EDT
Hi,
We bought two apple trees(McIntosh and Sweet 16) with flowers on them from Fleet Farm 2 weeks ago. Now, I realize the leaves (maybe 5-10 of each tree) have some spots. (The photos are from McIntosh and most damaged leaves, Sweet 16 has mild dots)
I just sprayed Cal-Foli yesterday and bought some other sprays online, but I haven’t received them.
Could you please help me with preventing more damage?
Washington County Minnesota
Expert Response
It looks like you have black knot —spots with pale centers and purple edges. There may also be cedar rust—orange irregular spots. Compare what you are seeing with the following website. There are also links that give treatment options. Usually no treatment is needed for rust. Fungicides are used for black knot when it continues annually.
https://apps.extension.umn.edu/garden/diagnose/plant/fruit/apple/leavesspots.html
You can send a sample to the plant disease clinic for verification. See: https://pdc.umn.edu/
Calcium sprays such as Cal-Foli are not usually needed unless a soil test indicates a need. I would not recommend using this especially on young trees.
Since these are newly purchased trees and if they have a guarantee, I would consider returning them. It is very unlikely that they developed these diseases in two weeks.
Another tip— pull back the mulch 6-8 inches. Mulch touching tree trunks can dehydrate trees and provide a place for pests to attack tree.
https://apps.extension.umn.edu/garden/diagnose/plant/fruit/apple/leavesspots.html
You can send a sample to the plant disease clinic for verification. See: https://pdc.umn.edu/
Calcium sprays such as Cal-Foli are not usually needed unless a soil test indicates a need. I would not recommend using this especially on young trees.
Since these are newly purchased trees and if they have a guarantee, I would consider returning them. It is very unlikely that they developed these diseases in two weeks.
Another tip— pull back the mulch 6-8 inches. Mulch touching tree trunks can dehydrate trees and provide a place for pests to attack tree.
Thank you very much for the response.
I was afraid of having them these diseases. Sweet sixteen with cedar rust and McIntosh with black knot, I believe.
They do have a guarantee for one year, I wasn’t sure if I needed to give them back ( I spent too much time just planting and they are my Mother’s Day gifts).
Do you think it would be possible to make them better next year or find healthy ones at the same place?
Thanks again!
From: ask=<personal data hidden> <ask=<personal data hidden>> on behalf of Ask Extension <<personal data hidden>>
Sent: Tuesday, May 28, 2024 12:11:17 PM
To: Ayca Ozutemiz <<personal data hidden>>
Subject: Re: Apple trees with disease (#0140260)
Sent: Tuesday, May 28, 2024 12:11:17 PM
To: Ayca Ozutemiz <<personal data hidden>>
Subject: Re: Apple trees with disease (#0140260)
Black knot can be controlled by chemicals such as Captan or sulfur products. These may not be needed if all infected leaves, fruit and branches are removed in the fall. See website above.
Cedar rust will continue if you have cedar trees in the area and it may spread to the other tree. There are no chemical treatments available to home gardeners. Consider replacing with a cedar rust resistant apple tree:
Cedar rust will continue if you have cedar trees in the area and it may spread to the other tree. There are no chemical treatments available to home gardeners. Consider replacing with a cedar rust resistant apple tree:
Cedar rust resistant Apple trees.
- Fireside
- Freedom
- Liberty
- Nova
- Easygro
- Novamac
- Redfree
