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How to Identify an Ash Tree Infested by Emerald Ash Borer

Updated September 15, 2020

John Ball

Professor, SDSU Extension Forestry Specialist & South Dakota Department of Agriculture and Natural Resources Forest Health Specialist

The emerald ash borer (Agrilus planipennis) is a threat to all the ash trees in our state. None of our native ash have any resistance to this insect and once attacked, unless insecticides treatments are started within a year or two, the tree will die. The emerald ash borer has been responsible for the loss of more than 60 million ash trees in the United States and Canada since its accidental introduction from Asia into Michigan during the 1990s.