White mold-like stuff on my apple trees.

Cotton? It's not bag caterpillars, is it?

Look a little closer for little green bugs, it's probably aphids.
Hit them with a dishsoap and water mix, then blast em off with the hose.

Kris

It's definitely not bugs. I have looked at it very closely and handled it.

I dont have my books but I think mwhat you are seeing is a type of scale called cottony cushion.

Try Oil-Away. It takes care of scale and small bugs by smothering them. You can get it through www.GardensAlive.com .

I had that on my prickley pear cactus last year and some of my rose cuttings have it this year. If you "sneak up" on it and grab the largest clump of "cotton", you may see something jump off. I don't know what bug it is, but I used insecticidal soap the get rid of it. I have also been quick enough to squish the "bug" and I just wiped off the "cotton".