apple disease problem

Asked June 26, 2018, 11:04 PM EDT

I started hobby orchard 5 years ago in SW Koochiching Co., about 50 apple trees, about 30 varieties. We got our first fruit last year. Trees are located on a south facing 3 % slope. The soil is a clay loam till with some sand lenses and would be classified as moderately well drained. All are standard sized trees, most came from St Lawrence Nursery in Potsdam, NY. I have only sprayed for insects a few times over the years. There were some small green caterpillars earlier this spring but that was all I've seen for insects this year. I used malathion for control. No mildew or anything else like rust has been noted. I have never used any fungicides. I have had issues with winter kill and die-back which is apparent before any leaf out. I know that this is not apple growing country. Now about 25% of the trees are being affected by what seems to be a disease problem. Other trees appear healthy, so far. The problem begins with leaves that are small, stunted and a pale green color then eventually curl up , then turn brown and die. Eventually the whole branch dies. Some trees, about 6, have totally died and others have just some branches now dead. On some trees it will occur on lower branches and on others the higher branches. Once it starts on a branch, the whole branch will die.. Other than the light color I have not seen any other indicator on the leaves. Dead trees have suckered, probably out of the root-stocks. I am not familiar with fireblight. I know there is no cure for it though. A photo is attached. Any input would be greatly appreciated. Thanks. Dave Potts Mizpah, MN

Koochiching County Minnesota

1 Response

That is definitively not fire blight nor does it appear to be any disease I am familiar with. I wonder if it is winter injury.
Limbs growing poorly and then dying is a common symptom.
Cut into on of the affected branches to see if the wood is brown.