Emerald Ash Borer


Emerald Ash Borer larvae live under the bark and feed on the vascular tissues under the bark creating galleries, effectively girdling the tree. The tree responds by sprouting new branches below the disrupted tissues. Dieback of the canopy is a symptom of Emerald Ash Borer larval infestation and as many as one half of the branches may die back as infestation progresses. The bark will split over dead vascular tissues, and trees may die within only two years of the onset of symptoms.


*TREE-age® insecticide is a Restricted Use Pesticide and must only be sold to and applied by a state certified applicator.


Treat your ash trees if Emerald Ash Borer is reported in your area. Do not wait for visible dieback in the canopy of the trees, as there is a significant delay between disruption to the vascular tissues and expression of symptoms in the canopy. Delaying Emerald Ash Borer treatment could result in canopy dieback or tree loss. Spring Injections can be made in the spring during the growing season, about 30 days prior to expected adult emergence. Uptake of formulation is fastest when trees are actively transpiring, after they have developed a full canopy. Emerald Ash Borer treatment in the spring will prevent the adult beetles from feeding and laying eggs in the tree. Summer Injections in the summer will kill the larval stage of EAB feeding under the bark. Make summer treatment applications in the morning when temperatures are moderate. If soil is dry, water trees prior to treatment. Fall Injections in the fall (before or after leaves color) can protect the tree now and the following season. The larvae are feeding now so they are doing a lot of damage to the vascular tissue. Proactive treatment is important since EAB larvae damage won’t exhibit symptoms until next year. The treatment will remain in the tree tissue and protect the tree through the next season. Trees need to be closely monitored for symptoms of EAB as infestation builds in your area. In general, applications are not made more than once a year. Specific insecticide formulations for EAB may provide 2 years of activity.

Destructive Pests of New Jersey

Asian Longhorned Beetle

The Asian Longhorned Beetle is a destructive pest of trees, originally from China. It can be identified by alternating white bands on long brown/black antenna. The appearance of small holes on trees can be an indication of infestation. If you see this pest please contact the New Jersey agricultural Extension Service at the link above.

Dutch Elm Disease

Dutch Elm Disease is a fungus which affects the American Elm. Symptoms begin as wilting of the leaves which turn yellow, and eventuelly brown. Dutch Elm Disease is a result of the fungus infecting and clogging the vascular system (Pholem) of the tree. This prevents water movement to the crown causing the browning and yellowing of the leaves, as the tree wilts and dies. The disease is spread by the Elm Bark Beetle. Certain fungicides, when properly injected, are effective in protecting elm trees from infection, and must be repeated every one to three seasons. Elm trees should not be pruned during the growing season because sap oozing from wounds may attract the Elm Bark Beetle.

Bacterial Leaf Scorch

Bacterial Leaf Scorch is an incurable plant disease that has infected an estimated 39 percent of oaks statewide. There is no cure for Bacterial Leaf Scorch, but with proper management affected trees can often be maintained for many years.Infected trees will need to be pruned, to remove infected limbs, and in many cases may need to be removed.

Emerald Ash Borer

The larval stage of the Emerald Ash Borer bores holes into the trunk and serpentine feeding galleries which disrupt the flow of nutrients as they rise up the trunk from the roots to the crown via the phloem (the tree's vascular structures) just under the bark, which eventually results in the death of the tree.

Hemlock Wooley-Adelgid

Adelgids are small insects, related to aphids. The hemlock woolly adelgid sucks sap from the young branches which results in needle drop and branch dieback.

Birch Leafminer

Birch Leafminer is an invasive wasp which lays its eggs into the leaves. Once hatched, leafminer larvae consume the tissues between upper and lower leaf surfaces causing brown blotches.” Healthy trees can withstand occasional attacks by birch leafminer. Repeated attacks can result in the general decline and death of the tree over time by secondary pests such as fungi and the bronze birch borer.

Common Spring-Time Diseases of Woody Ornamentals in the Landscape

Landscape Plants Rated by Deer Resistance

Pine Bark Beetles

There are many species of bark beetles that infest conifers. Adults tunnel through the bark, mate and lay eggs in the phloem, under the bark,where the larvae develop. Adults develop from pupae and emerge by boring out through the bark. Multiple generations a year are possible.

Leaf Chewing Caterpillars

Caterpillars are the larval stage of moths and are among the most serious defoliators of trees. The eastern tent caterpillar is responsible for defoliating forest trees, as well as cherry, apple and other ornamental shade trees. Others include the gypsy moth, winter moth, spring and fall cankerworm, bagworm, clear wing borers, pine tip moth and tussock moth. Some moth larvae, such as tip moths and clear wing borers, feed inside the twigs, shoots or trunk of the tree and are virtually unseen.

Sudden Oak Death

Oak Wilt

Oak Decline

Red Oak Borer

Iron Chlorosis

Phytophthora Root Rot


Apple scab

Forest Health in New Jersey

Oak Diseases

Armillaria Root Rot