Woolly apple aphids. I tend to ignore them even though over time they can take out a tree. They are most damaging on the roots so a resistant rootstock is good. If my memory is correct I have them now on roots of potted M7 and Geneva 30 but not on Geneva 11 and MM106. MM111 is supposed to be resistant.

Here is a link that might be useful: woolly apple aphid

I just visited an orchard of a commercial pest control consultant who advises central valley orchardists; he has access to all kinds of controls, but said blasting them with a hose has given as good of control as anything else he's tried. Resistant rootstocks such as M111, M106, and Northern Spy should be your norm from now on as if they're in the tree, they're in the soil where you can't get to them.

I had a Cox's Orange killed by them, relying on the advice out there that "they are no big deal." It took a couple of years, but they damaged all the tree's bark so much it just finally croaked. Blasting water works a little, but there is white fuzz back within a week, AND you have to hold the branch to effectively blast them off, so once a tree gets so big, that's pretty much a useless task. I now have them again on the one tree I didn't buy on M111, so I assume it will eventually die too, because they are impossible to effectively control. All my M111 trees are barely affected, so that is the only solution, IMO.

Carla in Sac

i have them on my apple tree as well and have been blasting them with high pressure water but they are over. what are they and what will kill them?? no apples this year so i will spray in the morning i guess. j

A quart spray bottle of water and a little bit of dawn works well for me. I only have a few trees so when I do my daily walk through, they get a taste of soapy water. Good luck, Bill