I would go to Google, and type in "Cedar Apple Rust", or "Apple Scab", and then click on "Images". Do either of those diseases match what you have? -Glenn

Burt: An apple tree 30 feet tall is too large to raise table quality apples, except perhaps for a few of the lower branches. "Loaded" is also not a good condition for the production of decent fruit. Apples must be thinned down to one or at a maximum two fruits per cluster to allow them to gain some size and quality, and sometimes even the clusters are too close together, requiring removal of an entire cluster. In most locations (and please tell us yours) apples are subject to a variety of insect pests and both trees and fruit can acquire diseases that can ruin the fruit, weaken the tree, or both. That is why it is usually necessary to spray apple trees, not only in the dormant season but especially early in spring just as the trees are setting their fruit. You cannot effectively spray a tree that is 30 feet tall. Agree with Glenn that your apples probably have scab, but that may not be their only problem. Plum curculio, codling moth, and apple maggot also work on apples, as well as a range of shield bugs such as stink and harlequin bugs. Many locations, such as mine, have to deal with cedar apple rust, which can infect both leaves and fruit. Use of an effective fungicide to cover the entire tree is necessary in such cases. I don't know why one adjoining tree would have no problems, but perhaps it has some genetic resistance to scab. Some varieties do, and that is why it would be helpful to tell us what varieties you have if you know them. If I had a large tree like yours, I would work on pruning it down to less than 15 feet, perhaps over a period of 2-3 years. Pruning in summer acts to reduce tree vigor, which is just what is needed in this case, so you can start now or any time. Restoring the ability of your tree to produce good apples will require considerable effort on your part, as well as a good deal of knowledge acquisition, and only you can decide if it is worth the trouble. But if your infected tree is capable of producing really good fruit, most of us apple growers would say yes. Don Yellman, Great Falls, VA

Yes the apples were just perfect on the outside, no soft spots, no marks of any kind, no dents, they were perfect. carla35, you are right, the brown areas started at the seeds and came to within about 1/4 of the skin. I was so shocked after cutting them in half. At least my Granny Smiths didn't let me down and a couple of them got damaged by being dumped in the shopping bag at the store by the bagger. The pie turned out great and my daughter did let me have one slice! Thanks for trying to help me figure this out. kat

It looks like bacteria spot. If it is bacteria spot, the spots will turn to holes. Not much you can do but get disease resistant varieties. Some of mine get it every year but usually it is in the late summer. I doubt the spray had anything to do with it. The tree looks healthy. When you sprayed for ants you probably also had aphids. The ants like to protect the aphids so they can eat the honey dew that the aphids secrete. With stone fruit the biggest problems are brown rot, worms (oriental tip moth and plum curculio) and scale. The brown rot can be controlled with fungicides. Tip moth and plum curculio can be controlled by insecticides sprayed when you see the fruits bitten by the beetles. Scale can be controlled by a dormant oil spray in the winter, and some add copper to the last dormant oil spray to help control brown rot and bacteria canker. It is easier to have 4 separate trees than a multigraft, but since it was a gift not much you could have done about that. You will have to prune to keep all the four branches about the same size so one does not dominate the others.