lows. The immature adelgid (nymph) over-winters on the bark of trees. Depending on climatic conditions, the nymph will come out of hibernation in late April to early May. By July the nymph reaches adulthood and begins laying eggs. Females, there are no males, may lay over 200 eggs throughout a six week period (Harris, 78). The adelgid that hatches is called a crawler and represents the only mobile stage of the insect’s life. The dark purple to black nymph is very small and is blown about the wind as it moves around on the tree. This is how the insect spreads to other trees.While in the crawler stage, the nymph searches for a desirable location to settle down and feed. When a favorable location is found, the adelgid attaches itself to the tree by inserting its long mouthparts into the living bark. Once it is attached and begins feeding, it becomes sedentary and starts secreting the white waxy material that covers it’s body.In late September and early October the second generation matures and begins laying eggs. It is the nymphs that hatch from these eggs that attach themselves to the bark and hibernate during the winter, laying the next seasons eggs the following July. Two generations are common in most areas, but as many as four generations may occur in lowland valleys (Holtrop, 95).The aphid sucks the sap from the living bark of the tree. As it feeds, it injects saliva, which causes increased tissue growth of the tree. This tissue growth results in differing damage depending on the location of the injury. Infestations of the tree most often occur in the following locations: under lichens or in cracks on the bark of main stems or large branches, along branch nodes of stems in the crown of the tree, and around new growth buds of twigs (Holtrop, 95).Heavy infestations on the trunk and main branches are whitish, appearing as a mass of tiny cotton balls or bits of wool. The adelgid injury on the trunk obstructs th...
