Hello, I have a 15 year old U of MN strain redbud tree that has become infested with very small bugs. There are clouds of them on the leaves. The bugs appeared in early summer and have persisted. I tried clearing them with a blast of water from my garden hose but that disrupted them for just a short time. I contacted an arborist who has not yet gotten back to me. He was here and said he had a landscaper who had observed the same problem. Recently, the bugs have navigated to a red-osier dogwood shrub in my yard, Please let me know what I need to do. Thank you! Judith Krause