Experts are keeping a wary eye out for the Asian long-horned beetle, which is killing trees in the Chicago area.Iowa State University entomologist Donald Lewis says that particular beetle attacks Maple trees. It hasn’t been seen in Iowa.Lewis says several thousand maples have been chopped down in Chicago.Lewis says in some ways, it’s like Dutch Elm Disease. However, Dutch Elm Disease spread faster — and spread underground from tree-to-tree. Companies in China have agreed to stop using untreated lumber for shipping crates to guard against shipping more Asian long-horned beetles to the U-S.