National Park Service Emerald Ash Borer (Agrilus planipennis)The Emerald Ash Borer (EAB) is an invasive metallic wood-boring beetle. Native to Asia, this invasive was introduced to North America in ash wood being used for shipping pallets and packing material. Emerald Ash Borer can be identified by their bright metallic green color and metallic purple and red abdomen which is only visible when the wings are spread. The most concerning impact of EAB is their preference to feed on, and eventually kill, native ash trees. Signs of an Emerald Ash Borer infestation include cracks in tree bark, woodpecker damage (blonding), and a thinning tree canopy. The most effective control method is insecticide treatment. Emerald Ash Borer may also be controlled biologically by small, stingless wasps that are known to control EAB in their native range in Asia. To prevent the spread of Emerald Ash Borer, don’t move firewood as EAB might be hidden inside. 
National Park Service Hemlock Wooly Adelgid (Adelges tsugae)The Hemlock Wooly Adelgid is an invasive insect that infests the Eastern Hemlock (Tsuga canadensis) trees of the Upper Delaware River region. Native to Asia, it’s suspected to have been introduced accidentally with ornamental Japanese Hemlocks. Hemlock Wooly Adelgid can be identified by the white, waxy masses females leave at the base of hemlock needles. The lack of natural predators and native plant resistance leads to large infestations. Additionally, one female can produce up to 40,000 eggs a year, allowing populations to increase rapidly. These insects impact Eastern Hemlock trees by tapping directly into the tree’s food storage cells, which leads to the death of the tree. Signs of a Hemlock Wooly Adelgid infestation include needle loss, branch dieback, and gray-tinted needles. Infested trees are also less likely to produce viable seed cones. Hemlock Wooly Adelgid is controlled primarily with either insecticide or the use of biological predators from its native range. Currently, there is ongoing research to determine the effectiveness of using the biological control beetle species Laricobius nigrinus or two biological control silver fly species, Leucopis argenticollis and L. piniperda to control Hemlock Wooly Adelgid. Spongy Moth (Lymantria dispar)Formerly known as the Gypsy Moth, the Spongy Moth is an invasive insect native to Europe and Asia. It was first introduced to North America by an artist named Leopold Trouvelot who was attempting to breed a hardy silkworm resistant to disease. Lacking natural predators, the Spongy Moth quickly spread after escaping Trouvelot’s home in Medford, Massachusetts. The Spongy Moth caterpillars are extremely devastating as they feed on the leaves of deciduous trees, sometimes defoliating entire trees. The caterpillars are gray to brownish with raised red, and three raised blue spots on their backs. They also have unusually large eyes and hairs along their bodies. Usually, infested trees can survive 2-3 years of defoliation but eventually become weaker and more susceptible to disease. To control the spread of the Spongy Moth, chemical and biological methods may be used. Small populations of Spongy Moth may be eradicated with mass trappings, mating disruption, and some pesticides. There are also small, nonstinging, biological control wasps whose larvae consume Spongy Moth eggs. A natural predator of Spongy Moth is the White-footed Mouse (Peromyscus leucopus), which feeds on Spongy Moth pupae. |
Last updated: March 1, 2024