Emerald ash borer: invasion of the urban forest and the threat to North America's ash resource.
The emerald ash borer (Agrilus planipennis, EAB), a phloem-feeding beetle native to Asia, was discovered killing ash (Fraxinus sp.) trees in southeastern Michigan, USA and Windsor, Ontario, Canada in 2002. Like several other invasive forest pests, the EAB likely was introduced and became established in a highly urbanized setting, facilitated by international trade and abundant hosts. Up to 15 million ash trees in urban and forested settings have been killed by the EAB. Quarantines in the United States and Canada restrict the movement of ash trees, logs, and firewood to prevent new introductions. Research studies are underway to assist managers leading eradication and containment efforts. Long-term efforts will be needed to protect ash in urban and forested settings across North America.