Spotting and Stopping Cincinnati’s Most Common Tree Pests

Trees play a major role in Cincinnati’s urban and suburban landscapes, but they’re often under attack from various pests that go after leaves, bark, and even roots. These pests don’t just make trees look terrible – some can kill trees surprisingly fast.

Knowing how to spot these common pests is key to keeping your trees healthy, especially when it’s warm out. Let’s look at seven common tree pests you might see in Cincinnati and how to deal with them to keep your trees strong and healthy.

1. Emerald Ash Borer

The emerald ash borer (EAB) is a small, metallic green beetle about half an inch long, with a distinctive bright green color. The larvae are creamy white and can be found under the bark of ash trees. They make S-shaped tunnels as they eat, which stops water and nutrients from moving through the tree, hurting and eventually killing it.

This pest targets all native ash trees in Ohio and is often spread unknowingly through the movement of infested firewood. EAB likes stressed trees but can attack healthy ones too, killing them in as little as two years.

Prevention:

• Avoid moving firewood: Don’t transport firewood or ash tree products, as this can spread EAB to new areas. Always purchase or harvest firewood locally.
• Regular inspections: Look at your ash trees regularly for signs of EAB, like D-shaped holes where beetles came out, S-shaped tunnels under the bark, or dying branches at the top of the tree. But never remove bark to find signs of EAB.
• Early treatment: By the time you see signs of EAB at eye level, it’s often too late to save the tree, as they start in the upper canopy and work their way down. Early treatment means staying aware of EAB activity in your area and applying treatments before your tree is affected.

Treatment:

• Systemic insecticides: Professional application of systemic insecticides can protect trees by killing larvae as they feed. Specific treatments are also available that target adult beetles before they lay eggs.
• Removal: Severely infested trees should be removed to prevent the spread to nearby healthy trees.

2. Asian Longhorned Beetle

The Asian longhorned beetle is a large beetle with long black and white striped antennae and a shiny black body covered in white spots. This pest likes hardwood trees like maples,

birches, and elms. The young beetles (larvae) dig deep into the wood, making tunnels that weaken the tree and can eventually kill it.

These beetles often spread when people move infested wood around, including firewood and wooden packing materials.

Prevention:

• Avoid moving firewood: Avoid taking firewood or plants from areas that have these beetles.
• Regular monitoring: Regularly check your trees for signs of the beetle, like big round holes where they exit the tree, sawdust-like dust at the base of the tree, or sap oozing out of the trunk.
• Early detection: If you think you’ve seen this beetle, tell your local tree or agriculture office right away. Quick action can help stop it from spreading and protect countless trees in your area.

Treatment:

• Tree removal: Unfortunately, once a tree has these beetles, tree removal is likely the only option to stop the beetles from spreading.
• Insecticides: You can use insecticides to protect trees that don’t have beetles yet, but these don’t work well once the beetles are inside the tree.

3. Gypsy Moth

The destructive gypsy moth is known for its caterpillars, which have blue and red spots along their backs. The adult female moths are white and flightless, while the males are brown and can fly.

Gypsy moths are attracted to a variety of trees, though they’re especially fond of oaks. Their larvae can defoliate entire trees, leading to stress and potential death due to the inability to photosynthesize without leaves.

Prevention:

• Maintain tree health: Healthy trees are more resistant to gypsy moth infestations, so proper watering, mulching, and pruning are essential. Planting trees in the right place, under the right conditions, can minimize stress and pest problems.
• Pheromone traps: Set up pheromone traps to catch male moths, which helps reduce the population.

Treatment:

• Biological control: Apply Bacillus thuringiensis (Bt), a naturally occurring bacteria, which is effective against young caterpillars.
• Manual removal: Learn what gypsy moth egg masses look like. You can scrape them off trees and other surfaces, then soak them in soapy water to kill them.

4. Bagworms

Bagworms are caterpillars that make distinctive bags for themselves using bits of the plants they eat. These bags look like small, pointed cocoons covered with pieces of leaves.

Bagworms mostly like evergreen trees like junipers and cedars, but they can attack many other types of trees too. You’ll often see their bags hanging from tree branches, but property owners often mistake them for pinecones and leave them to multiply and harm trees.

Prevention:

• Regular inspections: Keep an eye on your trees and remove any bags you find. This stops the eggs inside from hatching. A single bag can house up to 1,000 eggs.
• Encourage natural predators: Birds and some insects eat bagworms. You can attract these helpers by planting native trees and shrubs with berries, and those with thick, dense cover where birds like to nest.
• Proper tree care: Healthy trees are less likely to get bagworms.

Treatment:

• Hand-picking: In winter, you can remove the bags by hand and destroy them. This helps reduce the number of caterpillars that hatch in spring.
• Insecticidal sprays: If there are too many bagworms to remove by hand, you can use insecticide sprays. These work best in late spring when the caterpillars are young and more vulnerable.

5. Aphids

Aphids are tiny insects that are usually green or black. They often cluster together on new growth of plants. These little bugs suck sap from leaves and stems, which can make leaves curl, turn yellow, or stop growing normally.

Aphids produce a sticky substance called honeydew, which can attract mold and ants. They often like trees with lots of nitrogen, especially newly fertilized maples, birches, and roses.

Prevention:

• Avoid over-fertilizing: Use balanced fertilizers and avoid too much nitrogen, which can lead to the soft new growth that aphids love.
• Regular inspection: Look at your trees regularly for signs of aphids, especially during the growing season.
• Water management: Make sure your trees get the right amount of water. Healthy trees can better resist aphid attacks.

Treatment:

• Insecticidal soaps: You can spray affected areas with insecticidal soaps or neem oil to kill aphids on contact.
• Systemic Insecticides: For severe infestations, the application of systemic insecticides work well to reduce aphid populations to manageable levels.
• Beneficial insects: Ladybugs and lacewings eat aphids. You can attract these helpful bugs by planting flowers like dill, fennel, and marigolds. Try to avoid using broad insecticides that might harm these good insects. Bee-safe products are required for flowering trees like Lindens.

6. Scale Insects

Scale insects are small, oval-shaped pests covered with a waxy or shell-like coating. They attach themselves to bark, leaves, or branches and suck sap from the tree. This can cause

yellowing leaves, slow growth, and dying branches. Scale insects often attack trees that are already weak or stressed.

Prevention:

• Keep trees healthy: Water, mulch, and prune your trees regularly to reduce stress and help them fight off pests.
• Prune infested branches: Cut off and destroy branches with scale insects to stop them from spreading.
• Regular monitoring: Look at your trees frequently, especially in spring and early summer, to catch problems early.

Treatment:

• Horticultural oil: Spray horticultural oil to smother scale insects. This works best in late spring and early summer when the insects are most vulnerable.
• Systemic insecticides: For severe cases, you can use systemic insecticides. The tree absorbs these, and they kill the scale insects when they feed.

7. Japanese Beetle

Japanese beetles are shiny green and copper-colored beetles about half an inch long. They eat the leaves, flowers, and fruit of many types of trees and plants, often leaving behind skeletonized leaves. Their larvae, called grubs, live in the soil and eat grass roots and other plant roots, making these pests some of the hardest to deal with.

Prevention:

• Row covers: Protect young trees and shrubs with row covers to keep beetles away.
• Regular monitoring: Look for beetles often during their active season (late June to August) and take action early if you see them.
• Healthy soil: Keep your soil and grass healthy to reduce grub populations, which can turn into adult beetles.

Treatment:

• Hand-picking: You can hand-pick the beetles and drop them into soapy water to kill them.
• Neem oil: Spraying neem oil on plants can help deter the beetles from feeding.
• Insecticidal sprays: For severe infestations, you might need to use insecticide sprays specifically designed for Japanese beetles.

Let Lefke Tree Experts Help Protect Your Trees

Keeping trees healthy is the single most effective way to prevent pest problems in the first place. This includes things like soil improvements and proper watering routines. By keeping trees healthy, you give your trees the strength they need to naturally fight off pests if and when they inevitably do show up.

One of the best ways to boost overall tree health is regular pruning. Pruning helps to remove infested branches, improve air circulation and sunlight penetration, and eliminate crossing or rubbing branches, which can cause wounds and create an entry-point for pests.

If you’d like to boost the health and appearance of your trees, give Lefke Tree Experts a call today at 513-325-1783. Otherwise, if you have trees that are heavily infested, we can help remove those to prevent pests from spreading to other trees on your property.