Beech Leaf Disease in New Jersey: Signs, Treatment Options & What Homeowners Should Know

New Jersey is home to approximately 12 million beech trees, and a silent killer is systematically destroying them. Beech leaf disease has already spread to 16 counties across our state, turning the majestic specimens that define our most beautiful neighborhoods into dying trees.

If you live in Morris, Somerset, Essex, or Union County, the beech trees in your neighborhood may already be affected. Fortunately, arborists now have treatment options that can slow the disease and help protect infected trees when the problem is identified early.

Key Takeaways

• Beech leaf disease (BLD) is a fatal condition that causes leaf banding, canopy thinning, and eventual decline in American and European beech trees if left untreated.
• Arbotect 20-S injection treatment offers an effective solution for managing BLD in beech trees, with studies showing significant reduction in nematode populations and two-year symptom suppression when applied properly by licensed professionals.
• Optimal treatment timing is crucial for success, with June being the ideal window after full leaf expansion but before nematodes migrate to overwintering buds, which typically occurs by September.
• Treatment works best on larger beech trees (over 10 inches in diameter) with less than 50% canopy dieback, while severely compromised trees or those smaller than 5 inches in diameter are poor candidates for intervention.
• All beech trees within 38 feet of each other should be treated simultaneously because nematodes can spread that distance through wind, precipitation, and wildlife, making partial treatment of grouped trees ineffective against reinfection.

The dark stripes along leaf veins are the earliest visible symptom of beech leaf disease and typically appear during spring bud break.

What is Beech Leaf Disease?

Beech leaf disease (BLD) is a fatal disease targeting beech trees throughout the northeast; recently, it has been running rampant in New Jersey. This disease quickly kills young and mature beeches without intervention, typically within two to seven years.

The disease is most worrisome for the damage it can do to our native American beech (Fagus grandifolia). However, it also targets popular non-native species, such as European beech (F. sylvatica), Chinese beech (F. engleriana), and Oriental beech (F. orientalis).

WARNING: BLD is not the only disease to keep an eye out for with beech trees, as they also face threats from beech bark disease (BBD).

When Did Beach Leaf Disease First Appear in New Jersey?

BLD has become a new reality for New Jersey residents, and knowing how to keep our beech trees safe is about protecting your property and our natural ecosystem.

Arborists first detected BLD in Ohio in 2012, and the disease has quickly spread across much of the northeastern part of the country. In New Jersey, we first detected the disease in 2020 in Essex and Bergen counties. One year later, much of New Jersey reported the disease, including Morris County, Union County, and Somerset County. To date, we have confirmed cases of BLD in the following counties:

• Sussex
• Passaic
• Bergen
• Morris
• Essex
• Union
• Warren
• Camden
• Somerset
• Hunterdon
• Middlesex
• Gloucester
• Mercer
• Monmouth
• Burlington
• Salem

Why Beech Leaf Disease Is a Concern

The American beech is an essential part of New Jersey’s forest ecosystems, providing both shelter and food (beechnuts) for our local wildlife. The spread of the disease has caused anxiety among New Jersey residents, especially because the USDA Forest Service’s Forest Inventory and Analysis Program estimates there are approximately 12 million beech trees in the state.

Students and administrators at Princeton University have also expressed worry about BLD, which threatens to destroy the beautiful beech trees on campus and in the surrounding area.

What Causes Beech Leaf Disease?

Beech leaf disease is caused by a microscopic worm called a nematode. The species responsible is Litylenchus crenatae ssp. mccannii (often abbreviated as Lcm). These parasites feed on beech leaves and buds, damaging the tissue that the tree needs for photosynthesis and growth. Unlike many tree diseases, the nematodes do not attack the wood of the tree – they primarily affect leaf buds and leaf tissue.

The nematodes spend the winter inside infected buds. In late winter or early spring, they begin reproducing and laying eggs within the developing leaves. By mid-summer, the population increases, and symptoms become more noticeable as the growing season progresses.

Beech leaf disease spreads when nematodes move from infected trees to healthy ones. Wind and rain can carry them through the canopy, and studies show they may travel at least 38 feet from an infected tree. Insects, such as beech blight aphids, and even birds may also help transport nematodes to nearby trees.

What Are the Symptoms of Beech Leaf Disease?

The first apparent symptom of BLD is dark stripes or bands on the lateral veins of the leaves. Typically, you will notice these signs during bud break in the spring, and they may be unevenly distributed in the lower canopy. To help spot BLD, look up at leaves, as it is easier to notice the banding against the bright sky.

As the disease progresses, other symptoms will appear, such as:

• Heavier banding on leaves
• Smaller leaves
• Leathery texture
• Leaves appear crinkled, deformed, or shriveled
• Copper colored leaves
• Premature leaf drop
• Aborted bud development
• Thinning canopy

Multiple injection points ensure thorough distribution of treatment throughout the tree’s vascular system for maximum effectiveness against beech leaf disease.

How Do We Treat BLD in New Jersey?

While this disease may have once been a death sentence to trees, arborists have learned a lot about BLD since 2012, and we have developed treatment options to manage the disease and improve your trees’ health.

Arbotect 20-S: The Preferred Treatment for BLD in New Jersey

Arbotect 20-S has shown promising results in treating trees with BLD in New Jersey. It contains the active ingredient thiabendazole, which works as both a fungicide and nematicide, combating the nematodes and preventing leaf dieback. Arbotect 20-S has become our preferred method for treating beech trees.

The benefits of using Arbotect 20-S date back to a 2022 study, where researchers used the product and noted it lowered nematode populations in treated trees compared to untreated trees. The promising results of the studies have led New Jersey to create a special local label permitting the product’s use for treating BLD.

Professional arborists use a specialized macro-injection system to deliver Arbotect 20-S directly into the tree’s vascular system. The process requires proper equipment, technical expertise, and precise placement to be effective. The injection sites must be placed on the sides of the root flare, not the ridge of the root flare or the trunk. Improper injection placement can lead to tree decay and significantly reduce the treatment’s effectiveness.

“So far, we’ve seen positive results from using this treatment, and it has helped mature trees recover from the worst of BLD. We’re staying up to date on the newest developments in research for treating BLD, and we’ve been able to keep many local beech trees alive with well-timed treatments.” – Justin Mayberry, Certified Arborist at Alpine Tree

When to Treat Your Tree for BLD in New Jersey

The timing of Arbotect 20-S treatment is crucial for maximum effectiveness against beech leaf disease. In New Jersey, optimal timing is in June, after your beech trees have achieved full leaf expansion. The ideal timing for treating beech trees is prior to the nematode dispersing from leaves to maturing buds, which peaks in September.

The early summer window allows the treatment to circulate throughout the tree’s vascular system before nematodes establish themselves in overwintering buds.

While injections can be made through late summer or early fall, trees treated after mid-July may still show some symptoms the following spring. Trees injected late in the season exhibited some BLD symptoms the next year, but suffered less canopy dieback than controls.

PRO TIP: For the best results in treatment, we recommend scheduling a spring assessment with an arborist. They can examine your beech trees, confirm the presence of BLD, and then set up a treatment schedule for later in the year.

Which Beech Trees Should be Treated for Beech Leaf Disease

Not every beech tree with BLD symptoms is a good candidate for Arbotect 20-S treatment. ISA Certified Arborists evaluate these key factors to determine whether treatment will be effective and worth the investment:

• Tree Size: Trees that are 5 inches or fewer in diameter at chest height should not be treated. Treatment works best for beeches larger than 10 inches in diameter with sufficient vascular capacity to distribute the injection effectively.
• Disease Severity: Treatment works best for trees with less than 50% dieback or defoliation. Trees showing early leaf banding but maintaining most of their canopy respond much better than severely compromised specimens.
• Tree Value: Mature specimen trees, beeches providing critical shade, or trees with historical significance justify the treatment investment.
• Location Importance: Trees in prominent landscape positions, where loss would significantly impact your property’s appearance, value, or function, are prime treatment candidates.
• Overall Health: Trees stressed by other factors like drought, soil compaction, or construction damage may not respond as well to BLD treatment and may need additional care.

How Often Should Beech Trees Be Treated for Beech Leaf Disease?

Trees can be injected once every two years, making Arbotect 20-S a cost-effective long-term solution. Study results have shown two-year suppression of nematode populations, causing a reduction of BLD symptoms and overall dieback.

After two years, trees will need to be reassessed and, if necessary, retreated to prevent reinfection and decline. Arborists can monitor your treated beech trees and recommend re-treatment timing based on each tree’s individual response.

How to Support Beech Trees Recovering from Beech Leaf Disease

Lowering tree stress is an effective way to help your tree recover from beech leaf disease and prevent healthy trees from getting infected. Some simple ways to protect your beeches include:

• Provide water during a drought.
• Apply a two-inch layer of mulch around your tree. Avoid piling it around the trunk; the root collar (where the trunk flares out at the base) should always be visible.
• Limit mowing under the trees and eliminate foot traffic in the area to prevent soil compaction.
• Prune your trees to eliminate dead or diseased branches and those that rub against each other. Always sanitize pruning tools between cuts to avoid spreading diseases from one tree to another.
• Apply fertilizer if a soil test indicates a nutrient deficiency.

Frequently Asked Questions About Beech Leaf Disease

Can I treat my beech trees myself, or do I need a professional?

Arbotect 20-S treatment requires specialized equipment, proper licensing, and precise injection placement to be effective. Improper injection can cause tree decay and reduce treatment effectiveness. Only licensed professionals with the proper equipment should perform these treatments.

Is it too late to save my beech tree if it’s already showing symptoms?

Not necessarily. Treatment is most effective on trees with less than 50% canopy dieback. Even trees showing early BLD symptoms can recover with proper treatment. However, trees with severe dieback (more than 50% of the canopy affected) may not respond well to treatment and could be candidates for removal.

Are there any trees I can plant to replace beech trees if they die?

Yes, several native New Jersey species can provide similar ecological benefits. Consider planting American holly, black gum (tupelo), white oak, chestnut oak, or hickories. These species support local wildlife and provide year-round interest while being resistant to beech leaf disease.

If I have multiple beech trees, do I need to treat all of them?

For the best results, yes. It is not effective to treat some trees and leave nearby trees untreated. Treatment must be applied to all individual trees in an area because the nematodes can spread up to 38 feet from infected trees. Treating only some trees in a group may lead to reinfection from untreated neighboring trees.

Professional arborists use specialized macro-injection equipment to deliver Arbotect 20-S directly into the tree’s vascular system at precisely placed injection points.

Suspect Beech Leaf Disease in Your Trees? Call Alpine Tree for Diagnosis & Treatment

Beech leaf disease is spreading quickly across New Jersey, but early detection and treatment can help preserve many affected trees. Arborists can evaluate your beeches, confirm the presence of BLD, and determine whether treatment or removal is the best course of action.

At Alpine Tree, we’re staying at the cutting edge of treatment options, and we are committed to protecting our local beech population. If you see the symptoms of BLD in your trees, don’t wait to seek help! Call us at 973-964-7798 or request an estimate online to schedule a tree inspection and treatment program.