Is this really cedar apple rust?

Asked November 22, 2015, 11:42 AM EST

Hi, I just can't figure out for sure if this Honeycrisp tree I have really has cedar apple rust. Could you look at these leaves (attached photos) and tell? I have read the description of cedar apple rust and it doesn't seem the same. My leaves do have yellow spots but then the leaves turn partially brown and then eventually they all turn brown and fall off the tree. I do have a Crimsoncrisp apple tree but only a few leaves are infected and most do not fall off. I have tons of Junipers all over our 20 acres of woods and have searched for the galls but have not found any. I have treated my Honeycrisp tree with Neem and it helps but not completely. I read about a new idea of spreading corn meal around the base of the tree and spraying the tree with Potassium Bicarbonate on the leaves right in the Spring before spores might spread. I don't want to use any herbicides or anything poisonous for bees or animals so I hope this works. But we have over a 100 apple trees planted before we got here that are spread out all over our property in the woods and in our yard and they are all dying. The leaves turn yellow and fall off and the apples do not mature they just fall off and then eventually the tree dies. I am going to buy cedar rust resistant apple trees and replant but I just want to make sure this is what the apple trees have so I know for the future. Thank you

Dane County Wisconsin trees and shrubs disease issues apple trees honeycrisp apple horticulture

1 Response

Your honeycrisp may be suffering from a physiological disorder called honeycrisp chlorosis.
http://www.omafra.gov.on.ca/english/crops/facts/05-047.htm#leaf
Honeycrisp are also very sensitive to stress and too much or too little water will impact fruit production.
http://www.extension.umn.edu/garden/yard-garden/trees-shrubs/cedar-apple-rust-and-gymnosporangium-ru...
To know for sure if it is cedar apple rust the best thing to do is to send a sample to the plant disease clinic and get the leaf spots diagnosed.
https://pdc.umn.edu/