The fungus-farming polyphagous shot hole borer (Euwallacea sp. or, in other descriptions, Euwallacea aff. fornicatus) is wreaking havoc on trees in California, and it is difficult to control. A new study on several insecticides, fungicides, and combinations found “limited performance” in controlling the pest among all the formulations tested. (Photo credit: Jiri Hulcr, Ph.D.)