Question: Our weeping willow appears to be dying slowly. I see no visible insects, but there are holes in the trunk with sawdust pouring out of them. Is that borers? What can I use to stop them?

Answer: That’s cottonwood borers, to be specific. Unfortunately, they’re very large beetles (black and white, with long antennae over their backs) that move through the neighborhood. There isn’t much hope of controlling the adults. You can use a borer preventive spray to stop the entry of as many of the larvae as possible, but you’re fighting a tough battle. Cottonwood borers probably account for the death of 90 percent of all types of willow trees, usually within 5 to 10 years.