FOREST HEALTH: EMERALD ASH BORER The emerald ash borer (Agrilus planipennis) is a destructive, non‐native, wood‐boring pest of ash trees (Fraxinus spp.). Native to Asia, the emerald ash borer beetle (EAB) was unknown in North America until its discovery in southeast Michigan in 2002. Since then, the invasive pest has spread to 35 states including Texas, where it was first detected in Harrison County in Northeast Texas. EAB is responsible for killing millions of ash trees across much of the country. Ash trees are widespread in the United States and all 16 native ash species are susceptible to attack. Ash trees with low population densities of EAB often have few or no external symptoms of infestation. Symptoms of an infestation may include any or all of the following: dead branches near the top of a tree, leafy shoots sprouting from the trunk, bark splits exposing larval galleries, extensive woodpecker activity, and D‐shaped exit holes (see photo gallery for images). EAB is a significant threat to urban, suburban and rural forests as it kills both stressed and healthy ash trees. EAB is very aggressive, and ash trees may die within two or three years after they become infested.