What kind of bug spray do I use to control apple maggots, and do I use it right up to eating the apples?
This article should help: https://www.gardeningknowhow.com/edible/fruits/apples/apple-maggots.htm
I have an apple tree in my backyard and areas of it are showing dried leaves and the branch the leaves are on are dying also. I think it may be Fire Blight. What product should I use for fire blight?
If it is indeed fire blight, then this article should be of some help: https://www.gardeningknowhow.com/plant-problems/disease/fire-blight-remedies-and-symptoms.htm This article discusses other common apple problems, if you have not already seen it: https://www.gardeningknowhow.com/edible/fruits/apples/apple-tree-diseases.htm
I took a bud off and it is brown in the center when you cut it open and green around the outside. How can I fix this? (the apple tree is a prairie magic grown in zone 3).
This article may help:
https://www.gardeningknowhow.com/ornamental/trees/tgen/tree-leafing-problems.htm
Ants are eating my apple trees.
There are many types of ants. One that you might find on your trees is carpenter ants. This article has information on dealing with those: https://www.gardeningknowhow.com/plant-problems/pests/insects/home-remedies-carpenter-ants.htm
This article has some more information on other species of ant: https://www.gardeningknowhow.com/plant-problems/pests/insects/get-rid-of-ants.htm
Also, the ants may be traveling into your trees to feed on honeydew of aphids or scale, so you may want to treat for these: https://www.gardeningknowhow.com/plant-problems/pests/homemade-aphid-control-a-natural-way-to-kill-aphids.htm
I wonder if you could tell me if apple and Sharon tree in the garden near to the house will damage the building.
While I don't think there's any threat to the building itself, you may want to consider planting at least 5-10 away. You'll also want to keep them routinely pruned. Here is more info: https://www.gardeningknowhow.com/edible/fruits/apples/pruning-apple-trees.htm, https://www.gardeningknowhow.com/ornamental/shrubs/rose-of-sharon/pruning-rose-of-sharon.htm
My son-in-law has just moved and has an apple tree which has like a yellow fungus on it. Any ideas as to what it is and if it is worth trying to salvage?
The fungus is likely lichen or shelf toadstool. Neither are harmful to the tree but can indicate that the tree is suffering from something else. Does the tree look sickly otherwise? If not, then the tree will be fine. If it looks sickly, can you describe the symptoms and we will try to diagnose.
There are little golden spots on the limbs of my young apple trees. Just purchased and planted.
Cedar apple rust can cause yellowish splotches on the branches. Here is some information about it: https://www.gardeningknowhow.com/edible/fruits/apples/cedar-apple-rust-control.htm
Newly purchased trees with this, or any other disease, should be returned to the dealer. You may want to get a refund and try trees from a different grower. You can have the tree branches examined by the Extension Service, who will tell you exactly what is going on. This link will help you find the nearest one: https://www.gardeningknowhow.com/extension-search/