Hemlock Looper

• The eastern subspecies of this hemlock pest has a wide range, stretching from eastern Canada to the Rocky Mountains in Alberta, and bordering U.S. states. It typically feeds on mature trees, and while infestations typically only last two or three years, they do result in a large volume of tree mortality. The moths are very long-lived; they usually emerge in late summer or early fall and can continue to be active well into November.
  
  

Hemlock Borer

• This hemlock pest is particularly dangerous for the eastern hemlock. The larvae feed on the tree beneath the bark (although they do not create tunnels). However, they typically only attack plants that are already stressed (which is usually caused by drought or defoliation), and their ecological function is usually to aid in the decomposition of dead or dying trees. The larvae create galleries beneath the bark of the tree that destroys tissue that is necessary for the tree's survival.
  
  

Hemlock Needle Miner

• Unlike other species of hemlock pests, the hemlock needle miner tends to merely cause ornamental or aesthetic damage rather than killing the tree outright. Damage typically appears as several brown needles (referred to as "mined") bound together with silk.
  
  

Hemlock Wooly Adelgid

• Native to Asia, this hemlock pest threatens both the eastern and Carolina hemlocks. It is currently established in 16 states, ranging from Maine to Georgia, although the infestation and mortality has been most severe in such states as New Jersey and Pennsylvania. The larvae search out feeding sites at the base of needles and begin feeding on the stored starches in the tree, which are necessary for the tree's growth and survival. Death of the tree can occur within 4 to 10 years of the original infestation.
  
  

Elongate Hemlock Scale

• This hemlock pest, which hails from Japan, can be found in nine states, including as far west as Ohio. It attacks the lower part of the hemlock needle and removes important fluids through its piercing mouthparts. The damage typically manifests as dying limbs, starting from the bottom of the tree on upward as the number of pests on the needles increases. Trees typically die within 10 years, and even those that survive due so in a very weakened condition. Afflicted trees almost never fully recover and are typically unsightly.