How to Protect Trees from Spotted Lanternflies

Spotted lanternflies (SLF) are an invasive species that seriously threaten trees, plants, and agriculture. Originally from Asia, they have rapidly spread across various regions in the U.S., feeding on the sap of trees and damaging crops. These pests are hazardous because they damage various tree types, such as fruit trees, oaks, and maples, degrading their health and leaving them susceptible to other illnesses. Protecting trees from spotted lanternflies has become essential to prevent widespread damage to forests, orchards, and urban landscapes. Various control methods are available, ranging from physical barriers to chemical treatments.

Key Takeaways:

• A Multi-Method Approach is Essential: No single method can fully protect trees from spotted lanternflies. The most effective protection combines tree banding, insecticide sprays, and egg mass removal.
• Early Detection and Consistent Monitoring are Key: Spotted lanternflies are more easily controlled in their early stages, especially as nymphs. Always check signs of infestation, such as egg masses or early-stage nymphs.
• Environmentally Safe Methods are Available: Eco-friendly solutions such as neem oil and biological controls exist for those concerned about environmental harm. These methods offer a safer alternative to chemical treatments while still being effective in reducing SLF populations.

Tree Banding

Tree banding is a popular method for controlling spotted lanternfly populations by trapping the nymphs as they crawl up tree trunks. Sticky bands are placed around the trunk of a tree, creating a physical barrier that captures nymphs on contact. These bands are particularly influential because nymphs must climb upward to reach the leaves, where they feed.

How It Works:

• Sticky bands are wrapped around the trunk, creating a sticky surface that traps the nymphs as they move upwards in search of food.
• As nymphs crawl over the band, they become stuck, preventing them from reaching the canopy and continuing their life cycle.

Materials to Use:

• Commercial sticky bands are designed explicitly for tree banding.
• DIY alternatives, such as double-sided tape or adhesive-coated paper, can be combined with plastic wrap.
• It’s essential to check the bands regularly, as they can become filled with insects or lose stickiness over time.

How to Avoid Trapping Non-Target Species:

• Use mesh or wire guards around the sticky bands to prevent birds, squirrels, or other animals from accidentally getting stuck.
• Alternatively, sticky bands should be installed higher up the trunk, out of reach of small animals.
• Wildlife-friendly adhesive bands are also available to minimize harm to non-target species.

Tree Wrapping

Tree wrapping involves wrapping materials like burlap or fabric around the tree trunk. This method creates a protective layer that intercepts spotted lanternflies during migration, making it a simple yet effective tool for controlling SLF populations.

How It Works:

• Burlap or fabric is wrapped tightly around the tree, usually in two layers, with the top layer left loose.
• As the nymphs or adult lanternflies migrate upward, they get trapped between the layers of fabric. Once trapped, they can be manually removed and destroyed.

Benefits of Eco-Friendly and Reusable Options:

• Burlap is a natural and biodegradable material, making it an eco-friendly choice for tree protection.
• Fabric wraps can be reused multiple times throughout the season, reducing waste.
• Wrapping trees with these materials offers a chemical-free alternative, suitable for those concerned about the environment or for trees in areas with heavy wildlife activity.

Insecticide Sprays

Insecticide sprays are widely used to control spotted lanternfly populations by directly targeting tree pests. Two main types of insecticides are used: systemic and contact sprays.

Safe Application Methods:

• Timing of Application: Insecticide sprays should be applied when spotted lanternflies are most active (typically late spring through fall).
• Avoiding Harm to Beneficial Insects: To protect bees, butterflies, and other pollinators, avoid applying sprays during blooming periods or in areas where beneficial insects are active. Opt for selective insecticides that target SLF while minimizing impact on non-target species.
• Weather Considerations: Apply sprays when calm, as the wind can carry the spray to unintended areas. Avoid spraying before rainfall to prevent runoff into water systems.

Considerations for Specific Tree Species:

• Some tree species are more susceptible to insecticide damage. For example, fruit trees may need special care, as insecticides can affect fruit production. In such cases, using products labeled safe for fruit-bearing trees is essential.
• Systemic insecticides should not be used on trees that are near water sources, as they can leach into the soil and affect aquatic life.

Insecticide Soil Treatment

Soil treatments involve applying systemic insecticides to the tree’s base, which are absorbed through the roots and transported throughout the tree. This method provides long-term protection by killing spotted lanternflies as they feed on the tree’s sap.

How It Works:

• When systemic insecticides are sprayed on the ground surrounding a tree, the roots absorb the poison.
• The insecticide moves through the tree’s vascular system, targeting SLF that feed on the tree sap.

Adequate for Larger Infestations:

• Soil treatments are particularly effective for trees experiencing a severe infestation of SLF. They provide consistent protection, as the insecticide is continuously present in the tree’s sap for an extended period.
• This method benefits large trees that are difficult to treat with sprays alone.

Long-Term Protection but with Environmental Concerns:

• While soil treatments offer long-term protection, they raise concerns about environmental impact. Insecticides have the potential to seep into the groundwater and contaminate it, harming surrounding plants and animals.
• It’s essential to follow application guidelines carefully and avoid overuse, especially near sensitive ecosystems such as rivers, ponds, or areas with high wildlife activity.

Environmental Considerations:

• Use soil treatments as a last resort when other methods prove ineffective.
• To minimize environmental risks, avoid application in areas prone to soil erosion or near water sources.

Biological Controls

Biological control involves using natural predators to manage spotted lanternfly (SLF) populations. This method harnesses the power of nature, introducing or encouraging predators that feed on SLFs, which can help reduce their numbers without chemical pesticides.

Introduction of Natural Predators:

• Parasitic Wasps: Certain parasitic wasps are known to lay their eggs inside SLF eggs, thereby reducing the next generation of lanternflies. These wasps are being researched and introduced in controlled environments to curb SLF numbers naturally.
• Birds: Certain bird species, such as sparrows, have been observed feeding on spotted lanternflies. Although not a complete solution, encouraging bird populations in infested areas can help control SLF populations.
• Praying Mantises and Spiders: Other natural predators, such as praying mantises and spiders, may also contribute to SLF control by consuming adult insects and nymphs.

Effectiveness and Long-Term Sustainability:

• Biological control methods are considered sustainable because they offer long-term population management with minimal human intervention once established.
• Unlike chemical methods, which may need regular application, natural predators can continuously target SLF populations as long as their habitats are preserved.
• These methods also benefit from not harming non-target species or polluting the environment.

Ongoing Research into Biological Agents:

• Scientists are actively researching additional biological agents that could be introduced to combat SLFs. For instance, research is being conducted on potential fungi or bacteria that could act as pathogens to lanternflies.
• The challenge lies in ensuring that introduced biological agents specifically target SLFs without negatively impacting other species or ecosystems.

Neem Oil Application

Spotted lanternflies can be managed with neem oil, a natural insecticide from neem tree seeds. It works by interfering with the insect’s feeding and reproductive cycles, making it a popular choice for organic and eco-conscious pest control.

How Neem Oil Acts as a Natural Pesticide:

• Neem oil contains azadirachtin, which disrupts the SLF’s hormonal balance, preventing them from molting and laying eggs.
• It also acts as an antifeedant, meaning SLFs are deterred from feeding on the treated area once applied to a tree.
• When applied directly, the oil can suffocate young nymphs by clogging their respiratory systems.

Application Methods for Minimal Harm to the Environment:

• Foliar Spray: Blend neem oil, water, and mild soap into a spray and apply it directly to the tree’s leaves and trunk. This guarantees that the active components will target the pests without dispersing into unwanted areas.
• Soil Drench: A less common but effective method is applying neem oil to the soil around the tree’s base. The roots absorb the oil, which works systemically to protect the tree from within.

Apply neem oil when pollinators are less active, such as early in the morning or late at night, to reduce harm to helpful insects like bees.

Frequency of Application for Ongoing Protection:

• Neem oil is biodegradable and breaks down over time, so reapplication is necessary for ongoing protection.
• For efficient control, neem oil should be used every 7 to 14 days during the growth season, particularly in areas with high SLF populations.
• Regular monitoring is essential to determine if additional treatments are needed based on SLF activity.

Horticultural Oils

Horticultural oils are an effective and environmentally friendly method for controlling spotted lanternflies (SLF), especially in their early stages. These refined petroleum-based or plant-based oils work by smothering SLF eggs and young nymphs, effectively reducing future infestations.

Overview of Using Horticultural Oils for SLF Control:

• Horticultural oils are applied to tree trunks, branches, and foliage where SLF eggs and nymphs are found.
• They work by coating the eggs and nymphs with a thin film, which blocks their respiratory openings and causes suffocation.
• These oils are beneficial during the SLF egg-laying season, ensuring that fewer nymphs hatch in the spring.

Benefits of Smothering Eggs and Young SLFs:

• Non-toxic: When appropriately used, horticultural oils are safe for kids, pets, and helpful insects because they don’t contain any harmful chemicals.
• Egg Mass Reduction: Horticultural oils help reduce the number of nymphs that emerge in the spring by targeting eggs before they hatch, which can lessen the need for other, more aggressive control methods later in the season.
• Low Environmental Impact: These oils are an excellent choice for people worried about the environment’s health because they degrade swiftly in the environment and do not leave behind any hazardous leftovers.

Safe for Plants but Requires Regular Application:

When applied correctly, horticultural oils are generally safe for most trees and plants. However, some sensitive plants may show signs of damage, so it is essential to follow the label instructions.

• Timing of Application: For best results, apply horticultural oils during cool, dry weather, avoiding extreme heat or moisture that can reduce the oil’s effectiveness or damage the plant.
• Regular Application: Since the oils degrade quickly, they must be reapplied regularly—typically every 7 to 10 days—to provide ongoing protection against SLF eggs and nymphs.

Manual Removal

Manual removal is a highly effective, non-chemical method for controlling spotted lanternflies, especially early in the infestation. This method requires vigilance and effort but can significantly reduce SLF populations when combined with other control techniques.

Importance of Early Detection:

• Early detection of SLF infestations is crucial for successful manual removal. The sooner the infestation is identified, the easier it is to control before the population grows too large.
• It is essential to regularly monitor trees for egg masses, nymphs, and adults. Egg masses are often found on tree trunks, rocks, fences, and outdoor equipment, so scrutinize these areas.

Methods for Physically Removing Egg Masses, Nymphs, and Adults:

• Egg Mass Scraping: Use a scraper or plastic card to gently remove egg masses from tree trunks and other surfaces. Scrape the eggs into a plastic bag and destroy them with rubbing alcohol or hand sanitizer.
• Nymph Removal: Nymphs can be physically removed by hand or knocked off tree trunks using a soft brush or cloth. They can be crushed or dropped into soapy water to ensure they do not survive.
• Adult Removal: Adults can be caught by hand or with a vacuum designed for outdoor use. Since adults are more mobile, catching them early when less active can increase success.

Tools and Safety Tips for Effective Removal:

• Wear Protective Gear: When manually removing SLFs, especially adults, wear gloves and long sleeves to protect your skin from potential allergic reactions or insect bites.
• Use a Ladder Carefully: If egg masses or SLFs are higher on trees, use a sturdy ladder and ensure it’s placed on even ground. Always have a partner for safety when working at heights.
• Be Persistent: Manual removal is most effective throughout the SLF life cycle. Since SLFs reproduce rapidly, removing eggs, nymphs, and adults as soon as they are spotted is essential.

Tree Traps

Tree traps are specifically designed to capture spotted lanternflies (SLFs) as they migrate up tree trunks. These traps act as a physical barrier, intercepting and capturing the insects before they reach the canopy to feed.

Use of Specific Traps Designed for SLFs:

• Circle Traps: These are one of the most effective traps for SLFs. They consist of a funnel-shaped device wrapped around the tree that directs the SLFs into a collection container as they climb upward.
• Sticky Traps: Like tree banding, sticky traps use adhesive surfaces to catch the insects. However, these traps are designed to minimize the risk of trapping non-target species.

Placement, Maintenance, and Effectiveness in Protecting Valuable Trees:

• Placement: Tree traps should be placed around the trunk, typically several feet off the ground, where SLFs are known to travel. Please ensure the traps are snug against the tree to prevent SLFs from bypassing them.
• Maintenance: Regularly check the traps to ensure they work efficiently and are not complete. Sticky traps may lose their adhesiveness over time, so replacing them as needed is essential.
• Effectiveness: Tree traps are particularly effective for valuable trees in urban or orchard environments. They provide a non-chemical means of protecting trees. They can catch large numbers of SLFs, reducing their overall impact.

Avoiding Unintended Capture of Other Wildlife:

• Guarding Against Non-Target Species: Protective wire mesh or covers can prevent birds, squirrels, or other animals from being caught in sticky traps. These guard devices allow SLFs to enter the trap while keeping wildlife safe.
• Using Eco-Friendly Traps: Some newer trap designs use non-sticky surfaces or funnels, which pose less risk to non-target species. These are ideal for areas with high wildlife activity.

Egg Mass Scraping

Scraping off SLF egg masses is one of the most direct methods to control future populations, as each egg mass can contain 30-50 eggs. Removing these masses in the fall and winter months prevents new generations of SLFs from hatching in the spring.

How to Find and Scrape Off Egg Masses:

• Where to Find Egg Masses: SLF egg masses are usually laid on tree trunks, branches, and smooth surfaces like fences, rocks, and outdoor furniture. They resemble grayish-brown, mud-like patches about 1-2 inches long.
• How to Scrape Them Off: Scratch the egg masses lightly off the surface using a solid plastic card or scraper. Apply steady pressure, but be careful not to damage the tree’s bark or any other surface.

Tools and Best Practices to Avoid Tree Damage:

• Tools: A plastic card (like a credit card), putty knife, or a specialized egg scraper tool works well for this process.
• Best Practices:
  • Always scrape at a slight angle to minimize damage to the bark.
  • Use a ladder securely placed for high egg masses, and if possible, have a partner for safety.
  • Avoid scraping too deeply into the bark to prevent opening up wounds that may attract other pests or diseases.

Disposal Methods to Ensure Egg Mass Destruction:

• Soapy Water Method: Once the egg mass is scraped off, collect it in a container of soapy water or rubbing alcohol. The liquid will kill the eggs and prevent them from hatching.
• Burning: Another option is to place the egg masses in a sealed bag and burn them. However, due to local fire safety regulations, this method may only be suitable for some areas.
• Sealing in a Bag: Scraped egg masses should be disposed of quickly. They should be packed in a plastic bag and placed in the trash if feasible. The package should be sealed tightly to ensure that no eggs escape.

Removing Host Trees (Tree of Heaven)

The Tree of Heaven (Ailanthus altissima) is the preferred host plant for spotted lanternflies (SLF). These trees provide a critical feeding and breeding ground for SLFs, making them a primary contributor to the spread of these invasive pests. Removing these trees can significantly reduce the SLF population in affected areas. Since SLFs rely heavily on the Tree of Heaven to complete their life cycle, eliminating this host disrupts their breeding process, thus limiting the number of viable eggs laid each season.

How to Safely Remove This Invasive Species:

• Mechanical Removal: Cut down the Tree of Heaven as close to the ground as possible. Ensure that the stump is treated with an herbicide to prevent regrowth, as this tree can regenerate quickly from its root system.
• Herbicide Treatment: Apply systemic herbicides to the stump immediately after cutting. This ensures that the tree will not sprout new shoots and spread further. Herbicides like glyphosate or triclopyr are commonly used for this purpose.
• Root Removal: Whenever possible, remove the root system entirely. Tree of Heaven spreads through both seeds and root suckers, so eliminating the roots minimizes the chance of regrowth.
• Caution in Removal: Since Ailanthus trees are highly invasive, improper removal can lead to new sprouts and spreading. Use professional services to ensure thorough and safe removal, especially in dense tree-populated areas.

Impact on Reducing SLF Spread to Other Trees

By removing the Tree of Heaven, the primary host for SLFs, you significantly reduce their ability to reproduce and spread. With their favored food source, SLFs can move to more optimal trees, where they often have a lower survival rate. In areas where this invasive species is controlled or eliminated, the overall SLF population decreases, and the spread to valuable trees (such as fruit-bearing trees or hardwoods) is minimized. This method of host tree removal is especially effective when combined with other pest control strategies, providing a long-term solution to SLF infestations.

Natural Barriers

Use of Mulches or Ground Barriers Around Trees

Building a physical barrier around the tree’s base is an excellent way to prevent spotted lanternfly (SLF) nymphs from reaching the tree trunk. Mulches, gravel, or ground barriers can disrupt the movement of nymphs, which tend to crawl up tree trunks as they develop and migrate. This method works by obstructing the nymphs’ path, forcing them to expend more energy and decreasing their chances of successfully reaching the canopy to feed.

• Mulch Application: Dress the tree base with a minimum of 3.4 inches of organic mulch, like wood chips. This creates a dense barrier that nymphs struggle to crawl through.
• Gravel or Stone Barriers: Another option is to create a barrier with fine gravel or stones, making it difficult for nymphs to maintain traction as they climb over the uneven surface.
• Physical Ground Barriers: You can also use plastic or fabric landscaping barriers around the base of trees to prevent nymphs from reaching the trunk.

How It Prevents the SLF Nymphs from Reaching the Trunk:

• Disruption of Crawling Behavior: SLF nymphs typically move up tree trunks to access food sources in the leaves. Natural barriers like mulch or gravel disrupt this behavior, forcing the nymphs to either get trapped in the material or move to less favorable feeding areas.
• Encouraging Predation: By keeping SLF nymphs at ground level for more extended periods, these barriers may increase their exposure to predators, such as birds or other insects.

Complementary to Other Methods for Holistic Protection:

• Tree Banding and Wrapping: Natural barriers provide an added layer of protection when used in conjunction with tree banding or wrapping. The barriers slow the progress of SLF nymphs while banding or wrapping traps any nymphs that reach the tree.
• Insecticide Sprays: Mulch or gravel barriers can also be used alongside soil-applied insecticides, further ensuring that SLFs are stopped at ground level or killed by chemical treatments.
• Manual Removal: Ground barriers work well with manual removal strategies. By making it harder for SLF nymphs to reach the trunk, the barriers give homeowners more time to spot infestations and manually remove pests.

FAQs

What is the best time of year to start protecting trees from spotted lanternflies?

It’s best to start in late spring to early summer when nymphs are most active. This is when they migrate up the tree and can be trapped using bands or wraps.

Are insecticides safe for all tree types?

Not all insecticides are safe for every species. Always check labels and, if necessary, consult with an arborist to ensure you’re using a product that won’t harm your trees.

How can I protect non-target species when using sticky bands?

To protect birds and beneficial insects, use covers over sticky bands or try alternative trapping methods that are less harmful to wildlife.

Do spotted lanternflies affect all trees or just specific species?

While they prefer the Tree of Heaven, they also affect over 70 plant species, including maples, oaks, and fruit trees.

Can biological controls completely eradicate spotted lanternflies?

Biological controls can help reduce populations but are only a partial solution. It’s most effective when combined with other control methods.

Conclusion

Protecting trees from the invasive spotted lanternfly (SLF) requires a combination of methods to reduce populations and prevent widespread damage effectively. Each approach offers unique benefits, from physical barriers like tree banding and wrapping to biological controls and insecticide treatments. Neem and horticultural oils are environmentally friendly solutions that provide sustainable possibilities for continued protection. Still, early detection and regular monitoring are necessary to ensure their effectiveness. By employing a holistic strategy that includes removing host trees, using natural barriers, and manual egg mass removal, homeowners and professionals can safeguard valuable trees and help reduce the spread of this damaging pest. Together, these methods offer a comprehensive defense against SLF infestations while minimizing harm to the environment and non-target species.