I believe their called scales, those nasty little bugs that lay a cotton-like egg nest under leaves. They look like a tiny brown circle & they suck out sap from my tree, then it looks sickly. It's happened 2 yrs in a row, now they just came back.
We've had the tree sprayed with organic insecticide & we've used safer soap last yr, nothing seems to get rid of those bugs! And they usually spread from my snowbell to my Japanese maples & Yoshino tree. Please help!
parafin based dormant oil such as SunSpray (which i believe you can get at any box stores such as Lowe's and Home Depot)