The emerald ash borer (Agrilus planipennis or Agrilus marcopoli) also known as EAB, was accidentally imported from Eastern Asia in the late 1990s. Since then, the insect has made itself at home in vulnerable ash trees. EAB females bore into an ash’s bark and lay eggs. The resultant larvae bore further into the tree and into the cambium, the area between the bark and wood where nutrient levels are high. The larvae kill the trees by destroying the water and nutrient conducting tissues under the bark. Once an infestation is noticed it’s already too late. Learn more here.