I have approximately 25 cultivars in my yard and nearly 20 of them have developed black spots under the leaves after a recent unseasonably warm day. Closer inspection revealed tiny black insects diagnosed as "black aphids" by a local nursery. Leaves on all affected trees have turned brown or lost color entirely, curled up, and fallen off (No color this fall :( unfortunately). I'm interested in any suggestions on control and damage potential from the infestation. Can the insects damage the trees and how can I avoid a similar experience. Appreciate any input!