Missouri’s rich ecosystem, filled with a variety of trees and plant life, is home to a wide range of insects, both beneficial and harmful. While many insects play a vital role in pollination, decomposition, and natural pest control, others can be destructive, damaging and too often, killing trees and other plants. Understanding the balance between these insect populations is crucial for maintaining healthy landscapes and proper tree care. Learn who’s who below, so you can identify and manage them effectively.

Common Tree Pests in Missouri

While insects are essential to the ecosystem, some pose significant threats to trees, causing damage that can lead to weakening, disease, or even death. Here are some common tree pests found in Missouri:

Emerald Ash Borer

The Emerald Ash Borer is one of the most destructive tree pests in Missouri. This invasive beetle primarily targets ash trees, although it has been known to occasionally attack other species. The adult beetles lay eggs in the bark of ash trees, and the larvae feed beneath the bark, disrupting the tree’s vascular system. This leads to a slow decline and, in many cases, death of the tree.

Signs of Infestation:

• D-shaped exit holes in the bark
• Thinning canopy
• Bark splitting and sawdust-like debris around the base of the tree

Management: If you suspect an ash borer infestation, contact a certified arborist. While these pests have destroyed millions of ash trees in North America, early and aggressive care can minimize damage or save trees. Insecticide treatments may help protect healthy trees, but infected trees often need to be removed to prevent further spread.

Japanese Beetle

Japanese Beetles are a common pest that attacks a wide variety of trees, shrubs, and flowers in Missouri. These beetles feast on the leaves, causing skeletonization where only the veins remain. They are particularly attracted to fruit trees like apples, peaches, and plums.

Signs of Infestation:

• Holes in the leaves, giving them a “skeletonized” appearance
• Presence of beetles on the tree during the summer months

Management: Hand-picking beetles off trees in the early morning can be effective, as they are less active at that time. For larger infestations, insecticidal sprays may be necessary, but be cautious about using broad-spectrum insecticides that could harm beneficial insects.

Cottonwood Borer

This beetle targets cottonwood and willow trees, especially in weakened or stressed trees. The larvae of the Cottonwood Borer tunnel into the trunk, causing significant damage. Over time, this can lead to structural weakening and the tree becoming more susceptible to diseases and other pests.

Signs of Infestation:

• Sawdust-like material around the base of the tree
• Visible holes in the bark
• Dieback or wilting in the upper branches

Management: The best approach to managing this pest is to keep trees healthy. Prune dead or weakened branches and water the tree during dry spells. In severe cases, you may need to apply a systemic insecticide to control larvae.

Red Gum Lerp Psyllid

The Red Gum Lerp Psyllid is an invasive insect affecting eucalyptus trees, but in Missouri, it has been observed feeding on certain species of maples and other broad-leaved trees. The psyllid feeds on the sap, causing distorted growth and the formation of a waxy “lerp” covering that protects the insect.

Signs of Infestation:

• Small white, waxy “lerp” coverings on the underside of leaves
• Yellowing or curling of leaves
• Premature leaf drop

Management: Pruning affected leaves and maintaining tree health can help reduce damage. Insecticidal soap or neem oil can be used to treat psyllid infestations.

Beneficial Insects for Missouri Trees

While pests can cause significant damage, Missouri is also home to a variety of beneficial insects that play essential roles in maintaining a healthy tree ecosystem. These insects help with pollination, pest control, and overall tree health.

Ladybugs

Ladybugs, or ladybird beetles, are perhaps the most well-known beneficial insects. They feed on aphids, scales, and other small pests that can damage trees. A single ladybug can consume hundreds of aphids per day, helping to keep pest populations under control.

Benefits:

• Natural predators of aphids, scale insects, and mealybugs
• Reduce the need for chemical pesticides

Encouraging Ladybugs: Planting diverse species of plants that attract aphids and other insects will naturally draw ladybugs to your garden. Avoiding broad-spectrum insecticides also ensures that ladybugs remain unharmed.

Praying Mantis

Praying mantises are voracious predators that can help control pest populations around trees. They feed on a wide range of insects, including caterpillars, leafhoppers, and even small beetles. Their large size and strong hunting abilities make them a great ally for protecting trees.

Benefits:

• Excellent predators of caterpillars, grasshoppers, and other pests
• Help maintain a balanced ecosystem in your garden

Encouraging Praying Mantises: Praying mantises are attracted to gardens with dense vegetation, so providing plants that offer hiding spots is a good way to encourage them. They can also be purchased from garden centers as egg cases for release.

Parasitic Wasps (Various Species)

Parasitic wasps are some of the most effective natural pest controllers available. These tiny insects lay their eggs inside or on the bodies of pest insects, and their larvae feed on the pests. Some parasitic wasps target caterpillars, aphids, and even wood-boring beetles like the Emerald Ash Borer, which has killed millions of ash trees across North America.

Benefits:

• Control pests such as caterpillars, aphids, and borers
• Provide long-term pest management without the need for chemicals

Encouraging Parasitic Wasps: To attract parasitic wasps, plant a diverse selection of native plants that provide nectar and shelter for adult wasps. Avoid using pesticides, as they can kill the beneficial wasps along with the pests.

Bees (Various Species)

Bees play a key role in tree health by helping to pollinate flowers. In Missouri, many tree species, including fruit trees and flowering trees like dogwoods and magnolias, rely on bees for pollination. This results in healthier trees that can better resist disease and pests.

Benefits:

• Essential for pollinating flowering trees
• Enhance biodiversity and ecosystem health

Encouraging Bees: Planting native flowering trees and shrubs will attract bees to your garden. Avoid using pesticides, as these can harm bee populations. Providing bee-friendly habitats, such as bee houses or leaving areas of undisturbed soil, can also support their populations.

Insects are an integral part of Missouri’s ecosystem, with both harmful and beneficial species interacting with trees in various ways. While pests like the Emerald Ash Borer and Japanese Beetle pose serious threats to the health of trees, beneficial insects such as ladybugs, praying mantises, and parasitic wasps offer natural pest control that reduces the need for chemical interventions. By understanding the roles of these insects and taking steps to encourage beneficial species while managing harmful ones, you can help maintain a healthy and vibrant landscape in Missouri, benefiting both your trees and the broader environment.

Need Help with Your Tree Care? Call us Today!

The health of your trees depends on many factors, including healthy, nutrient-rich soil, proper hydration, sunlight and countless insects. You may rarely pay attention to those insects, but day in and day out thousands of beneficial insects are busy “battling bad bugs” and protecting your trees.

Our certified arborists and plant care specialists can help you identify problem insect infestation and develop strategies for eliminating them and showing you how to support beneficial insects. They can also assess the health of your trees, make recommendations regarding their care, offering you a full range of tree care services.

Contact us today! We’re here to help!