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This leaf disease affects a broad variety of deciduous trees. It thrives on cool, wet weather during bud break. This fungal disease can cause leaf damage and premature leaf drop.

Species of this insect are a frequent pest on many common landscape trees and shrubs. These sucking insects can damage plants through their feeding activity, can be a vector for other diseases, and help cause black sooty mold on plants that can discolor and damage the plant.

This fungal disease is a common disease on species of apple and crabapple trees. This disease affects newly developing leaves and causes green or brown lesions on leaves. Damaged leaves can appear deformed and are susceptible to drop earlier in the year. Pear trees can also get Pear Scab, which is very similar in symptoms and treatment.

This fungal disease affects several species of Ash trees. This disease creates easily visible orange spots and growths on leaves and can cause premature leaf drop. Appearance of this disease can vary considerably year to year and generally no treatment is required.

This disease affects several different Ash tree species and is caused by a microbe. Symptoms vary, but this disease causes slowed growth and general decline of the tree.

This bacterial disease has been found on a number of tree species, but in our region is frequently found to affect Oak trees. Symptoms include browning or “scorching” of the outside of the leaf and premature leaf drop.

This insect is most common on several species of evergreen trees, including arborvitae, pine, and spruce. The insect damages the tree by feeding on needles and leaves. The insect is most often noticed when it forms large bags or cases that suspend from branches.

This insect most often feeds on the leaves of Paper Birch and Grey Birch trees. The insect “mines” in between the upper and lower surface of the leaf, causing irregular brown areas on the leaves, with damage most often appearing first at the top of the tree. Damage can sometimes defoliate the entire tree.

This fungal disease affects most species of Plum and Cherry trees and shrubs. It causes distinct swollen “knots’ on the branches of trees and can cause dieback.

This destructive insect feeds on many plant species, but is a key pest of Rhododendron, Euonymus, and Japanes Holly, and Yew species. The larval stage of this insect feeds on roots and cause extensive damage or death. The adults feed on the leaves and cause notching damage.

This fungal disease is most commonly associated with European Beech trees. It is a potentially fatal disease if untreated that causes dark, wet looking areas on the bark. These cankers can severely damage and eventually kill the tree if untreated.

This fungal disease typically affects stressed or weakened trees and shrubs. Many different woody ornamental plants can be affected by this disease, which causes rough sunken areas on the bark and can cause branch dieback.

Most commonly associated with the Box Elder trees, these insects are most commonly noticed due to their tendency to invade homes and become a nuisance.

This fungal disease has been found in PA and NJ and affects boxwood species. Currently it is mainly a problem for nurseries. There is no current treatment strategy and any infected plants must be destroyed.

The American Boxwood is most often associated with this insect, although it does feed on other varieties as well. This sucking insect causes cupping and damage to growing leaves.

This boring insect can cause severe damage or death of entire limbs and trees. Damage usually appears first at the top of the tree. It affects white, paper, and cut-leaf weeping Birch trees.  This insect tends to attack stressed trees that are not properly irrigated and fertilized.

These ants aid in the decomposition of dead or dying wood where they form their nests. They are an occasional pest inside the home. While they do not tunnel into dry, sound wood in the home, they will excavate moist, rotten wood or other soft materials. It is rare for this tunneling to cause structural damage.

This fungal disease, and similar ones, affect juniper, apple, hawthorn, and serviceberry trees. Symptoms vary upon the species of the host tree, but generally include changes to leaf appearance and the fruit of the tree.

This insect causes bud and needle damaged most often to Blue Spruce and Douglas Fir, but also can affect Stika and Oriental Spruce trees. On Spruce trees, this insect can ruin the tree shape by damaging buds and forming pineapple shaped galls at the tips of growth.

This sucking insect affects a large variety of ornamental and shade tree. Damage can cause dieback of twigs and branches, and under severe conditions tree death.

This fungal disease affects Blue and Norway Spruces, causing branch dieback. The disease typically appears on stressed trees, particularly ones without adequate water. The dieback first starts on lower branches and proceeds up the tree.

This fungal disease affects a wide variety of Pine trees. Symptoms include the browning of new needles, new shoot death, and branch and tree death.

This fungal disease affects primarily the American Elm tree, but can also affect other Elm species. It is fatal if untreated as it attacks the vascular system of the tree.

This insect causes a gall at the end of new growth that can damage the appearance and shape of the tree. It most commonly damages Norway Spruce, but other Spruce species can be targets as well.

This presence of this insect can vary considerably from year to year. In peak population years, the insect can severely defoliate trees, and the large silky tents spun in the trees are unsightly. Wild cherry and other fruit trees are the preferred hosts, but they can attack a wide variety of trees.

These insects burrow beneath the bark of various Elm tree species and are important vector for the spread of Dutch Elm Disease, a serious and often fatal Elm tree disease.

This insect, which feeds exclusively on Elm trees, can severely defoliate trees and weaken them, making them susceptible to other insects and diseases.

Although found on other species, this introduced pest is a primarily a serious threat to Hemlock trees. This sucking insect can cause yellowing needles as well as needle drop and tree death.

This sucking insect causes a reduction in plant health, defoliating, and potential branch and plant death. Its primary host plants are deciduous and evergreen Euonymus as well as Pachysandra.

This introduced insect affects many species of Pine trees. They cause damage to new shoot growth that can result in wilted shoots and crooked trunks and branches.

These caterpillars feed on a large variety of deciduous trees and build large webs at the end of the branches. They do not usually cause significant damage, but their webs can be unsightly.

This bacteria can affect a wide variety of landscape trees, but is most frequently seen on apple and crabapple trees in the landscape. Symptoms are most often seen during flowering, and include wilting and blackened branches and flowers.

This sucking insect prefers Arborvitae and Yew species. The feeding action of this insect can reduce tree and shrub health and cause needle yellowing or drop.

Gummosis is the oozing of sap from the wounds or cankers of fruit trees. There are a number of possible causes, including tree injury, environmental stress, insects, and diseases.

The larval stage of this moth feeds on a fairly wide range of deciduous trees. This insect can severely defoliate trees, resulting in health declines or tree death.

This insect feeds on Canadian Hemlock trees, causing a reduction in tree health, and in more severe attacks, needle drop, branch loss, and even tree death. The telltale sign of this insect is the cotton like masses it creates on stems.

This insect attacks primarily Honeylocust trees by feeding on new leaves in spring. Feeding activity causes the new leaves to appear deformed with yellowish blotches and can cause defoliation.

This invasive beetle feeds on a large variety of landscape trees and plants, especially those in full sun. Feeding activity can cause extensive damage and creates leaves with a skeletonized appearance. The beetles are most noticeable in July and August, after they have emerged from the soil.

This insect feeds on a wide range of woody plants and trees, feeding through the bark of branches. Feeding activity can cause yellowing, dieback, and plant death.

This insect can cause affected plants to lose their usual vibrant color, and under severe attacks cause foliage and limb loss, or even plant death. Species of Juniper, Cypress, False Cypress, and Cedar can be affected.

There are a variety of lace bug species that feed on deciduous trees and shrubs, with a tendency for each species to specialize in only a few host plants. Lace bugs feed on leaves and cause leaf discoloration and leaf drop.

There are a variety of lace bug species that feed on deciduous trees and shrubs, with a tendency for each species to specialize in only a few host plants. The most common in our region are the Andromeda Lace Bug, the Rhododendron Lace Bug, and the Azalea Lace Bug.

Lichens are frequently found growing on the trunks of trees. They do not harm trees and not treatment or management is needed.

This insect feeds exclusively on Magnolia species and can cause a reduction in foliage, flowers and plant health, as well as dieback and tree death. In large infestations, twigs become enlarged and purple, and honeydew production creates black sooty mold on the plant.

As this non-native insect feeds it wraps a web around leaflets as it feeds on Honey Locust and Mimosa trees. Left untreated, they can defoliate an entire tree.

This insect feeds only on native Holly trees. Feeding and egg laying activity can damage leaves and cause premature leaf drop.

This fungal disease affects evergreen trees causing needle drop.

This insect feeds on Oak species, as well as Beech, Dogwood, Hickory, Maple, and Willow. The insect feeds by sucking nutrients from twigs and branches. Small trunks and branches can be disfigured by severe infestations.

This insect affects a wide variety of common landscape trees and shrubs. The waxy cover of this insect resembles a miniature oyster shell, giving the insect its names. Feeding on twigs and branches can cause branch dieback and in severe cases, plant death.

The preferred host plant for this insect are trees and shrubs in the genus Prunus. This insect causes damage as it bores into the tree near ground level. Damaged and stressed trees are particularly attractive to this insect. Keeping the base of the trunk clear of mulch is an important protection action.

This insect attacks a wide variety of Pine, Spruce, and Cedar species. This insect sucks on needles and its feeding activity can reduce tree health and cause twig and branch dieback.

This fungal disease appears on a wide ranges of plants, shrubs, and trees. This disease appears on the leaves of plants as white powdery fungus that can cause distorted leaves and premature leaf drop.

This boring insect most frequently affects Rhododendron and Azalea bushes in the landscape. Damage can decrease growth and blooms, cause dieback of branches, and tends to get worse each year if untreated.

This insect feeds on the needles of many Pine species and can cause aesthetic damage and defoliation. The European Pine Sawfly is the most common sawfly species found in our region.

The bacterial disease can affect a number of mature trees, particularly Elm species. Symptoms are quite obvious as cracks or wounds in the bark have liquid bubble from them and long streaks running down the bark.

This insect can cause visible damage to lawns, particularly during periods of drought as they chew and feed on grass.

This invasive insect damages a wide variety of trees and agricultural crops. When feeding, they expel significant amounts of honeydew that oftentimes coats the area and infested plants with honeydew and sooty mold. To stop the spread of spotted lanternflies, Willow uses an insecticide called dinotefuran. It can be applied as a trunk spray or trunk injection for highly effective treatment.

This destructive insect attacks a wide variety of evergreen trees. The sucking feeding of this insect causes trees to appear more yellow and less vibrant. As time passes, needles turn a rust color and can drop.

This recently arrived pest to our area can become a nuisance when they try to enter the home to overwinter.

This fungal disease primarily affects Black Walnut trees. The disease involve the interaction of walnut twig beetle and a fungus. It was first found in Bucks County in 2011. Damage inside of the bark leads to tree death.

Ticks are the vector that spreads Lyme Disease to humans, as well as several other tick-borne diseases. The blacklegged tick is the most common carrier of Lyme Disease in our region.

The feeding of this insect on the branches can cause deformed branches, as well as sooty mold growth. This insect is most commonly found on Tuliptree, Magnolia, and Linden.

This insect feeds on a wide range of landscape plants, shrubs, and trees. Feeding activity can cause leaves to look yellow or mottled in appearance and to drop prematurely.

This fungal disease enters the root systems of trees and disturbs water and nutrient movement within the tree. Symptoms include smaller than normal leaves and browning on the margins of leaves. Often symptoms first appear only on one side of the tree.

This recently arrived insect to Pennsylvania feeds on species of viburnum, a common landscape plant. The beetle feeds on the leaves of plants and can skeletonize and defoliate plants.

This fungal disease affects pachysandra, causing discolored leaves and sometimes plant death.

This insect attacks various Pine and Spruce species, as well as occasionally Douglas-Fir. This insect damages the terminal lead on trees and can damage tree structure and shape. This insect most comonly attacks trees under 20 feet in height.