The point is you don’t want to be using leaves from these trees, or any diseased tree for that matter, as mulch for your home garden, or around shrubs, or other trees. Leaves from fruit trees are especially suspect.
Apple scab is bad news. Those piles of leaves you hate to rake up are free, high quality fertilizer for the containers in your patio garden or the plot out back. This is particularly effective if you shred the leaves. Shredding makes the leaves decay–decompose–quicker. Also, if you’re using less fertilizer, you will be discharging less polluted water into nearby streams or lakes.
The whole shredding process is pretty easy. If your autumn leaf production is covering your lawn, just mow the lawn. Then if your mower has some way to collect the grass clippings and the shredded leaves, like a bag, you just empty the bag into any larger container and spread the resulting mulch wherever you need it. Some gardeners just till the shredded leaves/clippings into the ground.
A rotary tiller works well for this process. You can also use the grass clippings, shredded leaf mixture to make compost. Composting is an entirely different topic, well beyond the scope of this short piece, but very quickly it should be said that the mix of leaves and grass clippings make a well balanced compost.