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Forest Health in New Jersey
State Forestry Services surveys New Jersey's forests both from the ground and the air for various insects and diseases. While hundreds of insects and diseases damage our forests, foresters suppress only those that spread quickly and will not weaken on their own. Often the worst pests and diseases are non-native and introduced to our forests accidentally. Without their native predators, these pests will thrive and spread.

More Information
US Forest Service | USDA APHIS | NJ Department of Agriculture

		Southern Pine Beetle (Dendroctonus frontalis) Details This fast-moving bark beetle killed over 14,000 acres of southern NJ pines in 2010 alone. Susceptible Species SPB attacks all species of pine including pitch, shortleaf, Virginia, white, loblolly, and red. Signs of Infestation Pitch tubes, exit holes, fading crown, S-shaped galleries under bark Affected Areas Pine forests in southern New Jersey More information on Southern pine beetle from State Forestry Services				Gypsy Moth (Lymantria dispar) Details Larvae feed from May-June. Often confused with Eastern tent caterpillar. The high gypsy moth population in New Jersey can be attributed to reduced activity of the fungal parasite Entomophaga maimaiga. The reduced activity is due to lack of precipitation. Susceptible Species Prefers oaks and but also attacks many deciduous trees and shrubs Signs of Infestation Defoliation, oval egg masses, caterpillars Affected Areas Statewide More information on Gypsy moth from the US Forest Service

		Hemlock Woolly Adelgid (Adelges tsugae) Details Nymphs and adults feed on sap from the tree's twigs. This insect has infested all 26,000 acres of Hemlock stands to some degree in New Jersey. Some hemlock stands have been destroyed, while others have only low HWA infestations. Susceptible Species Eastern hemlock Signs of Infestation Egg masses, dying limbs Affected Areas Statewide More information on Hemlock woolly adelgid from the US Forest Service				Emerald Ash Borer (Agrilus planipennis) Details The invasive destructive insect, Emerald Ash Borer, has been found in nearby states Maryland, New York, and Pennsylvania. Susceptible Species White ash, green ash Signs of Infestation D-shaped exit holes, woodpeckers Affected Areas Not yet found in NJ More information on Emerald ash borer from the US Forest Service

		Asian Longhorned Beetle (Anoplophora glabripennis) Details The larvae of this invasive species feeds on the heartwood Susceptible Species maples, willows, poplars, ash, horse chestnuts, elm, and buckeye trees Signs of Infestation 3/4" to 1 1/4" adults, 3/8" exit holes, oozing sap, sawdust Affected Areas Union and Middlesex Counties More information on Asian longhorned beetle from the US Forest Service				Sudden Oak Death (Phytophthora ramorum) Details Plant pathogen found in CA, OR, WA, FL, GA Susceptible Species 75 Species including many oaks Signs of Infestation Brown leaves, large bleeding cankers Affected Areas Not yet found in NJ More information on Sudden oak death from the USDA APHIS

		Bacterial Leaf Scorch (Xylella fastidiosa) Details The bacterium is transmitted to healthy trees by feeding leafhopper and spittlebug insects moving from diseased herbaceous plants, such as goldenrod, blackberries, and clover, to healthy trees. This disease continues to be a serious health threat to urban shade trees in NJ. Susceptible Species Red, pin, and scarlet oaks, sycamore, elm. Signs of Infestation Brown discoloration along leaf margins. Affected Areas South-western New Jersey More information on Bacterial leaf scorch from the US Forest Service				Beech Bark Disease (Nectria coccinea) Details Fungus invades through bark wounds created by aphid-like insects Susceptible Species American Beech, European Beech Signs of Infestation Sparse foliage, woolly scales, ooze on trunk, small red fungal fruiting bodies Affected Areas Northern New Jersey More information on Beech bark disease from the US Forest Service

		Scarlet Oak Sawfly (Caliroa quercuscoccineae) Details Repeated defoliation may affect vigor or kill the tree Susceptible Species Red and white oaks Signs of Infestation Skeletonized or transparent leaves, defoliation starting in upper crown, larvae feeding on leaves Affected Areas Northern New Jersey More information on Scarlet oak sawfly from the USDA Forest Service				Thousand Cankers Disease Details A tiny bark beetle, the walnut twig beetle when combined with the Geosmithia fungus result in tree dieback and mortality. Found as close as Bucks County, PA. Susceptible Species Black walnut Signs of Infestation Branch dieback, many small cankers on branches and bole, tiny bark beetles, circular or oblong cankers under bark, tiny entrance and exit holes Affected Areas Not found in NJ yet More information on Thousand cankers disease from the USDA Forest Service

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