Synanthedon acerrubri
Hosts: Maple, boxelder. Red and sugar maples are favored hosts; other maples may also serve as hosts.
Damage: Larvae often invade wounds made by cossid, cerambycid, and buprestid borers. Invasion prevents or slows callus formation and sometimes enlarges wounds. Sap-stained, sunken, and swollen areas on the bark of branches and trunks of hosts often indicate infestation. Wounds in bark that are slow to close should be inspected. Prying open bark at infested sites will reveal feeding cavities and often tunneling larvae--sometimes six or more at a site. Although some frass may be ejected, much of it is packed under the bark. Branches are sometimes badly scarred and gnarled with numerous round exit holes in the bark.
Range: Found along Atlantic Coast through the eastern half of the United States and northward into Canada.
”- James D Solomon: (1995) Guide to Insect Borers in North American Broadleaf Trees and Shrubs©