Diseased apple tree

[lyonzd]

I have a relatively small apple tree, that has been in the ground for about 5 years. Hasn't done much of anything since we planted it, except for a few new shoots every year. But right now it seems to have some kind of disease. The tops of the leaves have orange circles on them, and on the underside of the leaves, there are little hairs growing where the spots are. I have not idea what this could be, how it happened, or what to do.

[Natural Designs]

it is a rust disease

here is a little info about it

https://www.ca.uky.edu/agc/pubs/ppa/ppa23/ppa23.htm

[dorothydot]

I agree, Cedar/Apple rust is the most likely culprit. Next April, locate some cedar/arborvitae right after a rain. This is the alternate host for the disease. It doesn't hurt these evergreens, but it looks surrealistic. They get what looks like an orange Christmas tree ball... that mated with a tiny slimy octopus. Seriously - gelatinous orange tentacles grow out of the orange balls. Pretty dramatic looking.

But these Martian-like tentacles are the seed spores of the Apple rust you're experiencing. As the tentacles dry out, the spores are wind-scattered to apple and often crabapples within a mile or so range.

The best solution for the Apple Tree standpoint is to plant resistant varieties. Which you don't seem to have inherited.

Dot

[UncleDave]

I've seem this many times. I lived next to an apple orchard when I was young and this was a common happening on some of the trees. I'm sorry to say I don't know what they did to prevent or treat it.