Pruning focuses on removing dead or diseased branches with minimal damage done to the tree.

Prune diseased branches back to healthy wood, and keep soil moist but not soggy.

Next, look for dead or diseased branches.

Cut back dead, broken or diseased branches to sound wood.

Several times the author mentions removing dead, diseased or damaged branches and burning them.

And is it OK to prune the diseased branches back at this time of year?

Other than removing diseased or broken branches, pruning of older trees should consist of cutting back to the same point each year.

Many flowering trees and shrubs don't need to be pruned, except for the removal of dead, diseased or injured branches.

This school has been unwell, and it is time to cut back the diseased branches.

Pruning of diseased branches and tips will help with the overall look of the tree, but not prevent or stop the spread of the disease.