Emerald Ash BorerThe emerald ash borer (Agrilus planipennis) is a deceptively attractive beetle. They are bright, metallic green insect and roughly twice the size of a grain of rice, 8.5 -14 mm long and 3.1 -3.4 mm wide. They start life in an egg only 1 mm long. The newly hatched larva can grow to 32 mm long over a year or two of development. They chew their way through the cambium layer of a living tree’s bark and create a zig-zag tunnel behind it that prevents the flow of nutrients through the tree’s bark in that area. When many larvae chew enough of these tunnels, the tree can be entirely girdled and will quickly die. The larvae overwinter before pupating in the spring and emerge as adults about 3 weeks later. The adult beetles create a “D”-shaped hole as they emerge from the tree. Adults feed on the leaves and soon fly to find mates to begin the cycle anew.