Ask Mr. Smarty Plants

Non-native to the United States, Salix x sepulcralis is a hybrid of a Chinese species (Peking willow) and a European species (white willow), and is said to grow in Zones 5 to 8 in the United States. It is weak-wooded, fast-growing and, therefore, short-lived. It has aggressive roots, can lift sidewalks and interfere with sewer lines, often growing on soil surface, making a problem with mowing. It is susceptible to a number of pests and diseases, and notorious for littering the ground beneath it. It also falls out of the expertise of the Lady Bird Johnson Wildflower Center, as we specialize in plants native to North America. In addition, we're not really entomologists, and probably can't identify the bugs you are dealing with. See this University of Florida Extension website on Weeping Willows for more information as well as this Q&A from North Dakota State University Extension on weeping willows.

This Iowa State University Department of Entomology website on Bark Aphids may help you identify your bugs. And you might also contact your Michigan State University Extension Office for Mason County. They could have more specific information, particularly if there is an outbreak in this sort of problem in your area.