Worried About Emerald Ash Borer and Other Pests? 5 Tips to Prevent Tree Insect and Disease Damage

Spotting a tree disease or insect infestation early can mean the difference between saving a tree and facing costly removal. With so many local trees lost to pests, it’s more important than ever to protect the ones we have left. From emerald ash borer to other destructive insects, knowing how to prevent infestations and disease damage can help keep your trees healthy for years to come. Here’s what you need to know.

Key Takeaways:

• Look for abnormal signs on your trees during regular inspections.
• Winter pruning protects against pests and diseases since trees can heal while insects are dormant.
• Proper soil nutrition and hydration are essential for trees to fight off infections, especially in residential areas where yard maintenance interrupts natural decomposition cycles.
• Target chemical use to specific high-risk or valuable trees rather than general application, with timing based on local weather patterns and Growing Degree Days.
• While beneficial insects can help control some native pests in Morris County, they’re ineffective against invasive species like emerald ash borer and spotted lanternfly.

5 Tips to Prevent Tree Insect and Disease Problems with Your Trees

As Benjamin Franklin famously said, “An ounce of prevention is worth a pound of cure.” While he might have been talking about people, the same wisdom applies to trees.

Preventing tree insects – like emerald ash borer or hemlock woolly adelgid – and diseases such as beech leaf disease from taking hold is crucial. Many Mendham Township residents may recall the town’s effort to proactively remove over 250 ash trees before emerald ash borers could destroy them, a process that impacted popular trails and hiking spots in 2024.

Early detection and preventive measures prevent you from having to remove a tree. Early treatment has several benefits, including:

• Lower tree care costs
• Higher chances of keeping trees alive
• Healthier, more attractive landscapes

The good news? A few simple preventive steps can keep your trees safe from Morris County’s most destructive insects and diseases. Here’s what you can do.

The exit holes left by emerald ash borer. Look for signs like this when inspecting your trees.

Perform Regular Inspections

Regular tree inspections help detect problems early. It’s hard to ignore your trees since they are so big, but many homeowners don’t pay any attention to their trees until it’s too late.

When inspecting your trees, look for any apparent signs of insect or disease problems. Though every bug or fungus has a different way it impacts trees, there are some typical warning signs that something is wrong, including:

• Discolored leaves
• Dead patches in the canopy
• Early leaf drop
• Fungus growing on your tree
• Holes or damage in the bark
• Increased insect activity

If you notice any of these signs, it could indicate a pest problem. To diagnose exactly what you are dealing with, have an arborist inspect your property as soon as possible. A professional assessment can confirm the issue, identify the best treatment options, and help prevent further damage to your trees.

Prune Your Trees Properly and at the Right Time

Beyond aesthetics, pruning provides several health benefits. Pruning can limit the risk of dealing with attacks from insects and diseases in a few ways:

• Increase Light Penetration and Airflow: Allowing light and wind to reach the lower portions of the canopy will decrease the risk of fungal diseases developing.
• Eliminate Diseased Branches: Diseased branches contain pathogens that can spread the disease to other sections of the tree or nearby trees. Always sterilize your tools after pruning a diseased branch to avoid spreading the disease to the next tree you cut.
• Reduce Competing Branches: Competing branches can rub against each other, exposing the wood under the bark. These openings serve as perfect entry points for pests to attack your trees.

Just as important as pruning itself is ensuring the right timing. Trimming creates wounds, which the plant attempts to seal with sap. While it recovers, pests may use these wounds as an opening to cause harm.

To avoid leaving a tree vulnerable, we recommend pruning most species in the winter. Pests are dormant in the winter, and a tree will have plenty of time to recover before they become active again.

Give Trees the Nutrients They Need

When you’re sick, getting as much food and water as needed to fight the infection is essential. A healthy body is much less susceptible to illness; the same principle applies to trees.

Trees rely on nutrients in the soil to grow and remain vigorous. In a forest, where fallen leaves and branches naturally decompose, the soil remains full of nutrients to aid trees. However, you will likely remove these branches and leaves in your yard. This can leave a tree struggling to get the nutrition it needs for all its normal functions, including fighting off diseases and insects.

Conduct a soil test to determine which nutrients your soil lacks. Armed with this knowledge, you can then apply a targeted fertilizer treatment to replenish the missing macro- and micronutrients. Giving a tree extra energy helps it fight off infections.

WARNING: Ensure your tree has enough water before you apply any fertilizer. Trees need ample hydration to absorb nutrients in the soil. Without it, the fertilizer can damage the roots.

Apply Preventive Treatments to At-Risk Species

Morris County has some of the biggest trees in New Jersey. Many of them are at the Willowwood Arboretum, though other large trees dot our region. One of the best ways to keep these trees standing is to apply chemicals before pests can attack them.

Preventive insecticides and fungicides can help lower the chance of damage from pests for your at-risk trees. We don’t recommend this service for all trees. Instead, consider it for specific trees, such as:

• Old and high-value trees you can’t afford to lose
• At-risk species (ash, oak, hemlocks are some common ones in our area)
• Trees that have dealt with insects and diseases in previous seasons

“We try to limit the amount of chemicals we spray because they can cause some collateral damage to other plants in a homeowner’s landscape. But for your most important trees, preventive fungicides or insecticides can really make a difference and keep them alive when pests are most active.” – Mason Swartout, Operator and Licensed NJ Pesticide Applicator at Alpine Tree

The timing of these treatments will vary each year, depending on the weather. Pests don’t follow our calendar; they become active based on weather patterns.

Morristown, like the rest of New Jersey, can have unpredictable weather. Spring may come early one year and late the next. An expert will know the appropriate time each year for preventive treatments to achieve maximum effectiveness by using the concept of Growing Degree Days.

Introducing beneficial insects (like the ladybug pictured above) can help control some pest populations.

Introduce Beneficial Insects on Your Property to Counteract Pests

Controlling dangerous pests doesn’t have to involve chemicals. One of the best chemical-free ways to control insect pests is to introduce beneficial bugs on your property.

Beneficial insects, such as ladybugs and parasitic wasps, are natural predators of some common insects in Morris County. Adding them to your landscape can reduce pest populations without the need to spray anything.

Predatory insects are not a perfect solution, unfortunately. They cannot effectively control the populations of invasive species, such as emerald ash borer or spotted lanternfly.

Frequently Asked Questions About Managing Tree Insects

It can take a lifetime to understand the nuances of preventing tree problems. We’ve compiled some common questions we hear from homeowners to help you better understand how to protect your property from pest damage.

What are some common tree insects and diseases in Morris County, NJ?

Some of the common threats we face in Morris County include:

• Emerald ash borer
• Spotted lanternfly
• Hemlock woolly adelgid
• Carpenter ants
• Scale insects
• Bacterial leaf scorch
• Beech leaf disease
• Beech bark disease
• Fire Blight

Can I spray fungicides and insecticides myself in New Jersey?

Homeowners typically don’t need a license to apply insecticides or fungicides, though you won’t have access to the same products as professionals. Applying chemicals can be dangerous for you and your landscape, which is why we recommend hiring a professional to maintain safety.

Should I be worried about my trees if my neighbor’s trees seem to have a pest problem?

If you notice a problem with your neighbor’s trees, inform them so they are aware of the problem. Insects and diseases can spread from tree to tree, so we recommend having a professional perform preventive services to lower the risk of the disease or pest spreading.

A tree displaying the typical symptoms of beech leaf disease, another crucial concern for homeowners in Morris County.

Alpine Tree Can Help Your Trees Stand Up to Insects and Diseases

Insects and diseases have taken down countless trees across New Jersey, but you don’t have to let yours be next. Early detection and proper care can make all the difference in keeping your trees healthy and pest-free. Whether you need preventive treatments, pest management, or expert advice, Alpine Tree is here to help. Call us today at 973-964-7798 or request an appointment online.