Are Japanese Beetles Mainly an East Coast Problem

No, while Japanese beetles were introduced in the early 1900s in the eastern United States, they have since expanded throughout most of the country. As of today they are no longer exclusively an East Coast problem.

Over recent decades, the pest has steadily expanded westward, establishing destructive, reproducing populations in Midwestern and Western states. Since the 1990s, it has been slowly expanding and is now widespread across Colorado’s Front Range urban pockets (MFY note: the urban corridor along the eastern foot of the Rockies, from Fort Collins to Pueblo). It has also spread as far as parts of the Pacific Northwest and recently they are found in pockets of population in several western states.

In response to this ongoing westward spread, the western states and the National Plant Board in collaboration with the USDA-APHIS (MFY note: the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service) developed the Japanese Beetle Harmonization Plan in 1998. The plan aims to create a common framework for nursery and plant material movement toward preventing accidental introduction in the western US. The plan enforces strict quarantine protocols, nursery certification, trapping, and compliance agreements to protect uninfested crop acreage, ornamental nurseries, and turfgrass from significant feeding damage.