What's your question? Ask

Many insects will eat burlap!!! Not that it is a bad idea, but there are other means to protect your fruit without harsh chemicals.

A few of my favorites to add to water and spray are: Neem oil, Hot pepper extract, garlic oil, clove oil, rosemary oil, and many others. All of these are effective alone, or mixed, and will deter many pests without being toxic to you. Just make sure to wash the fruit before you consume to avoid and bad flavors.

This collection of articles will help you in crafting your own natural pesticides, as well as many other organic gardening methods and tips: https://www.gardeningknowhow.com/special/organic

This article will help: https://www.gardeningknowhow.com/ornamental/trees/tgen/tree-leafing-problems.htm

This article will help you in preventing apple tree insects and fungal issues: https://www.gardeningknowhow.com/edible/fruits/apples/pests-affecting-apples.htm

This collection of articles will offer many ways to craft your own pesticides, as well as many other very useful organic gardening tips: https://www.gardeningknowhow.com/special/organic

This sounds like Sooty Mold.
This article will help you.

https://www.gardeningknowhow.com/plant-problems/disease/how-to-get-rid-of-sooty-mold.htm

I agree, if treatment and pruning has not been successful at this point, I would look for a replacement.

Talk with your County Extension Office and get a list of Apple Tree varieties that will do well in your area.

https://www.gardeningknowhow.com/extension-search

There are ways to go about this, but it is not advised, as it requires quite a bit of training to work with the hazardous chemicals properly. Some services will offer sterilization, though.

This article will help: https://www.gardeningknowhow.com/ornamental/trees/tgen/fruit-tree-sterilization.htm