Which invasive beetle pest attacks and kills ash trees?

The invasive beetle pest that attacks and kills ash trees is the emerald ash borer.

The emerald ash borer (Agrilus planipennis) is a metallic-green jewel beetle native to northeastern Asia. Its larvae feed beneath ash-tree bark, tunneling through the tissues that carry water and nutrients. This disrupts the tree’s circulation and eventually causes canopy dieback and death.

The species was first identified in North America near Detroit, Michigan, in 2002, although it may have arrived earlier in shipping materials such as wooden packing crates. In its native range, natural predators and more resistant ash species help keep populations lower. Outside that range, it has become highly destructive, especially to North American ash species such as green, black, white, and blue ash.

The other options are beetles, but they target different hosts: Colorado potato beetles attack potatoes and related crops, Japanese beetles feed on many plants, and Asian longhorned beetles attack a broad range of hardwood trees. Quarantines, insecticides, tree removal, and biological control are used to slow the borer’s spread.