Those are Wolly Apple Aphids; the white stuff is the wax they secrete to cover their bodies. The aerial infestations you see in the tree are easily controlled by ladybugs, who eat all but the fuzzy white stuff or by oil soap spray. A dormant oil spray in winter will also help.

Where they become serious is when they move through cracks in clay soil to infest the roots, where they cause galls that diminish the root's ability to move nutrients. If they become a serious problem, you should plant your trees on Wolly Apple Aphid-resisistant rootstock such as M111 or M106.

Applenut

Thank you!

I did spray with a copper dormant spray last winter for leaf curl that worked really well. I may have to get the oil spray this coming winter too.

I looked all over the internet for some indication of what I was dealing with and just came up empty handed.

You're a gem!

Deborah,

Many copper sprays can be mixed with horticultural oil for stone fruits, to control their pests, too. Copper is sometimes used at much lower concentration on apples or pears against firebllight. Follow label directions.