If you're removing them completely you could do that at any time. The trigger for regrowth should be removed along with the whole branch and if there is regrowth it can easily be rubbed out as it appears. If you have the hopes of leaving some of it to turn into fruit bearing wood the best odds are late summer. If you tip prune in winter/spring the result is regrowth of branches.

Hi, Sakura! I think you would come to love your trees even more if you would service them yourself. Pruning isn't difficult, and there is no precisely right method. Most important, you can become one with your trees and you needn't worry about causing permanent harm. Here are some basics: 1) You be the boss! Shape and size the tree the way you want. Don't be afraid to make cuts. 2) Start by removing any suckers, then 3) remove any dead or seriously diseased limbs, then 4) remove any branches that are too low, then 5) remove any hangers, then 6) remove watersprouts, then 7) remove any branches growing toward the center of the tree, then 8) remove any crossing branches--leaving the stronger or more important, then 9) remove any mummified fruit, then 10) top the tree if it's getting too tall to suit you. Shape it like a Christmas tree with no upper limbs shading lower limbs. Use limb spreaders to force 70-90 degree angles with the central leader. Stand back and throw your hat through the tree. If it won't sail through, cut some more to allow good air circulation and spray penetration to minimize the disease that so concerns you. Thin your fruit big time. Live life to its fullest. Perhaps Harvestman will weigh in with his thoughts!!! Good luck, Misterbaby.

i prune.. when i walk by with a saw ... or when they pist me off so bad.. i actually walk all the way to the saw and back.. just to teach them a lesson ... i suppose there is always a perfect time .... but i NEVER remember at that time ... lol ... i just trimmed up some oaks ... do you know how to make such large cuts???? a pic would bring you specific guidance ... and NEVER make just one cut .... to avoid trunk injury .... the last cut ... the branch should be no longer .. than a foot or two ... ken

This is a late comment, when air-layering bear in mind that sometimes it takes the air-layered plant over a year to form adequate roots, so the time that you start the process is really non-critical. The only exception being if you are in an area where the air-layer might freeze, or become excessively dry. But since you are in zone 10, you shouldn't have to worry about the freezing part, and if you keep the air-layer moist, (but not soaking wet), it should be successful. The only other thing to keep in mind is that some plants do not air-layer well. Plants with fleshy roots, (pawpaw for example)