burtmoore-
Sounds like it's probably "Apple Scab". Do a Google image on that and see if that's your culprit. Can you tell us where you are located? If that's the case, others here can help you with how to handle it. Do you know the apple varieties?
-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

Thanks for the information. I admit to being a novice, but I got caught a little off guard. Okay, I guess the tree is only about 20 feet tall (my wife thinks taller). This is the first year I have gotten anything as far as apples. Last year about 8, all good. This tree is a little bit early bloomer and we usually have a late frost that takes care of that. This year, lots of blooms and nice weather. I know now to spray at the correct time. If the weather cooperates and I don't screw up some other way, I may have better luck. Thanks for your advice. I certainly is apple scab, by the way. I think they will still be good to use in my trap to catch and relocate the pesky wood chucks.

Where are the brown spots, what variety is the apple and have you sprayed anything.

I have figured out Malathion injury to McIntosh and Cortland is brown spots where the drips form and it's not limited to McIntosh and Cortland.

Burt:

Relocate woodchucks? Mine get relocated to woodchuck heaven. Woodchucks are very destructive in the garden and nobody really wants any more of them. Mine (we call them grounhogs here) wouldn't go for apples, which are all over the place, but can't resist a quarter of fresh cabbage perhaps with a garnish of a peach. Just caught one last week, and he is at the 7-11 unless the trash containers have been emptied.

Don Yellman, Great Falls, VA