Emerald Ash Borer

Agrilus planipennis — the emerald ash borer (EAB) — is one of approximately 6,500 species in family Buprestidae (the metallic wood-boring beetles, jewel beetles) and the most economically destructive forest insect ever introduced to North America. Native to eastern China, Korea, and the Russian Far East, the species was first identified in North America in Detroit and Windsor in 2002 (likely arrived in wooden shipping pallets during the 1990s). Within 20 years EAB had killed an estimated 100 million mature ash trees across the eastern and central US and southern Canada. The species attacks all 16 native North American ash species (genus Fraxinus): white ash, green ash, black ash, blue ash, pumpkin ash, and others; only one native species (blue ash) shows partial resistance, and even that is regularly killed in heavy infestations. Adults are 8.5-14 mm long with brilliant metallic emerald-green elytra and a coppery-purple iridescent abdomen — among the most beautiful native-or-naturalized insects in North America. Larvae bore characteristic S-shaped serpentine galleries through the inner bark and outer sapwood, disrupting water and nutrient transport; a single tree typically dies within 3-5 years of initial infestation. Estimated total economic damage to municipal tree budgets, residential property values, and forest products through 2030 exceeds $30 billion. Federal and state quarantines, biological control releases (parasitoid wasps from the species' native range), and protective insecticide treatments have slowed but not stopped the spread. The species has now been documented in 36 US states and 5 Canadian provinces.