Common Insect Pests That Are Harmful to Trees

Trees are crucial to the health of our ecosystem. They help keep the air clean and cool, preventing soil from washing away. They also serve as homes for many different species of animals. Pests can majorly impact the health of trees and the surrounding ecosystem. Various tree pests are covered in this blog, along with their identification, prevention, and control.

Insects

One of the most widespread causes of tree damage is caused by insects. They can be harmful because they eat plant matter (such as leaves, bark, and roots) and spread illness. Insects that commonly inhabit trees include:

Beetles

Beetles are a large family of insects that can be found in many different shapes and sizes. The emerald ash borer, the Japanese beetle, and the pine bark beetle are all examples of common tree beetle species.

Caterpillars

Adult butterflies and moths develop from caterpillars. The leaves and needles of trees can be consumed, and some species can defoliate an entire forest. Common caterpillars that feed on trees include the tent caterpillar, gipsy moth, and fall webworm.

Aphids 

Aphids are tiny, delicate insects that gorge themselves on tree sap. These pests can cause curling, wilting, or yellowing leaves and even spread disease. Green peach aphids and woolly aphids are two examples of common tree aphids.

Scale Insects

Scale insects are tiny, stationary insects that feed on tree sap by attaching themselves to branches. They can spread illness and cause leaf yellowing or even complete leaf drop. Hard and soft scales are found on trees, but the former are more prevalent.

Mites

Tree mites are small spider-like arthropods that subsist on tree sap. They can spread disease and cause leaf discolouration or even death. Spider and rust mites are only two examples of the many kinds of tree mites.

Diseases

Diseases caused by viruses, bacteria, and fungi can also strike trees. Bark, Leaves, and roots are susceptible to damage from these pathogens and, in some cases, death. The following are examples of common tree diseases:

Fungi

Roots, Leaves, and bark are all fair game for the myriad of fungal diseases that may ravage a forest. Fungi cause diseases including anthracnose, powdery mildew, and Dutch elm disease and affect many different kinds of trees.

Bacteria

Trees can wilt, turn colours, and develop cankers from bacterial illnesses. Bacterial leaf scorch and Fire blight are two frequent kinds of tree bacteria.

Viruses

Trees infected by a virus may develop abnormally and change colour. Tomato spotted wilt virus and apple mosaic virus are two common tree viruses.

Defoliators

Gypsy Moth

Since 1980, the gipsy moth has been responsible for the annual defoliation of over a million forest acres. Moths lay hundreds of eggs on newly emerging leaves each spring, and those eggs will hatch into caterpillars later in the year. The larvae of this moth eat oak, birch, elm, and maple leaves.

In the spring, you can find up to 500 eggs in yellow, teardrop-shaped egg masses attached to tree trunks. Defoliation or other severe damage to the foliage is possible. 

Western Tent Caterpillar

The western tent caterpillar feeds on many trees but especially loves fruit trees, willow, poplar, quaking aspen, cottonwood, and others. Their white silk tents are a dead giveaway in the middle to late spring. The larvae form a colony, sharing food and growing a larger shelter as the season progresses. Western tent caterpillar infestations start with shrivelled or brown leaves and defoliation on the top and exterior branches.

Douglas-fir Tussock Moths

In urban areas, the Douglas-fir tussock moth is not limited to attacking Douglas-fir trees; it can also target blue spruce and other fir species. The tussock moth is notoriously persistent. Thus, trees are frequently attacked year after year until they are severely weakened. Larvae can be seen for the first time in late April when they begin consuming young needles. Tussock moth damage appears as reddish brown spots on leaves, first on the tree's upper and outer branches and then on the lower and inner branches. In addition to seeing egg masses in the lower tree canopy, you should be cautious not to touch the emerging larvae, as their tiny hairs can cause skin irritations and allergic responses.

Wood Borers

Emerald Ash Borer

Each year, the emerald ash borer destroys millions of ash trees. The adult emerald ash borer is tiny and hard to see, but infested trees will have serpentine, S-shaped feeding tubes full of frass and sawdust. Holes in the shape of a D may appear in the bark as the adults emerge later in the season. Emerald ash borer infestations are often identified by the characteristic symptoms of top-to-bottom crown dieback and leaf yellowing in ash trees.

Asian Longhorn Beetle/Borer

In the late 1990s, the Asian Longhorn Beetle was discovered in Brooklyn, New York, and since then, it has spread to more than 14 other states. The presence of the feeding galleries weakens the afflicted tree, and eventually falls. Asian longhorn beetles can cause leaf yellowing or drooping and sawdust accumulation at the tree's base. Pests can be spread by moving infested firewood or other wood debris from trees harbouring them.

Bark Beetles

Bark beetles come in a variety of species and can cause damage to both hardwoods and conifers. It is the beetle's infectious diseases that do the most damage. As the beetles go from tree to tree, they disseminate infected spores.

Conifers with reddish-brown needles radiating from the crown downward or deciduous trees with brown or white pitch tubes on the exterior of the bark are both symptoms of bark beetle infestation.

Sap-Sucking Insects

Aphids

Honeydew is the sticky syrup aphids leaves behind after eating the sap in tree leaves and stems. New leaf growth can be stunted, and leaves can curl or become yellow if aphid populations explode. Aphid infestations can be detected by inspecting the underside of leaves for the bugs themselves or by looking for sooty mould drawn to honeydew.

Scale Insects

Yellowing leaves slowed development, branch dieback, and even tree death can all be caused by scale insects feeding on the inner bark. Scale insects are easily spotted on leaves and twigs because of the sooty mould they leave behind and the colourful clusters they create. Infected trees should be treated during the final weeks of winter to prevent their return in the spring.

Keep your eyes peeled for these potentially fatal insects right now. Before it's too late, consult a local arborist if you notice any of the indicators above of insect infestation, including the peculiar yellowing or premature drop of leaves on your tree.

Balsam Wooly Adelgid

Adelgids are soft-bodied aphids with piercing-sucking mouthparts that only feed on coniferous trees. They are an invasive bug species that was probably introduced from Asia. Hemlocks fall prey to the Hemlock Woolly Adelgid, whereas firs are the target of the Balsam Woolly Adelgid.

Black Turpentine Beetle

The range of the black turpentine beetle extends from New Hampshire to Florida, westward to West Virginia, and eastward to Texas. All Southern pines have been the target of attacks. Pine trees exploited for naval stores or timber production are especially vulnerable to this insect. The beetle has been shown to attack damaged and healthy urban pine trees. 

Pest Control For Trees

The best method to protect your trees and keep them healthy is to stop pests from ever infesting them in the first place. Some strategies for warding off tree pests are listed below.

Cultural Methods

By taking appropriate care of your trees, you can increase their resistance to pests, which can be achieved through cultural means. Some cultural strategies include:

• Selecting trees that thrive in your climate and are not easily damaged by pests is an important first step in tree care.
• Removing diseased or broken branches regularly may encourage your trees to flourish.
• Irrigation: Keep your trees healthy and robust by watering them regularly.
• Fertilisation: Help your trees thrive by giving them the nutrients they need.

Chemical Methods

Chemical techniques may be necessary if cultural measures are insufficient to avoid tree pests. Some chemical approaches are listed below:

• Pesticides: If insects eat or destroy your trees, you can use pesticides to stop them.
• Fungicides: These can be used to treat existing fungal diseases or prevent further infection in your trees.
• Systemic pesticides in the soil hinder pest movement through plant tissues.

Biological Control

Using parasites and predators found in nature is at the heart of biological control for tree pests. Some examples of biological ways of control are:

• Natural predators, such as ladybirds and lacewings, can be introduced to help reduce tree-damaging pests.
• Pheromone traps can entice pests away from your trees, where they will be trapped.

Combining these methods can keep your trees healthy and pest-free.

Environmental Impact Of Tree Pests

Insects and other pests that feed on trees can seriously affect ecosystems, economies, and human health. Insects, fungi, and bacteria are some of the most common tree pests, and they may damage trees and other plants. Some ways in which tree pests harm ecosystems, economies, and people are outlined below.

Effect On The Ecosystem

There are many ways in which tree pests can upset the natural order of things. Oxygen production is stunted when pests strip trees of their leaves, and air quality suffers. In addition to reducing biodiversity, pests can damage trees, leaving them open to attack from additional pests and diseases. Displacement of native species by invasive pests can disrupt food webs and lead to biodiversity loss.

Economic Impact

Tree pests can significantly affect the economy, especially in the farming and logging sectors. It might damage fruit and vegetable crops and lower timber prices. Trade barriers and effects on foreign markets may also result from invasive pests.

Human Health Risks

Some insect pests of trees can be dangerous to people. Lyme disease can be transmitted to people by tree-dwelling ticks. Humans exposed to some varieties of mould that thrive on trees may experience respiratory issues.

Tree pests not only have these other negative effects but can also reduce the beauty of landscapes and wilderness places by damaging the trees' appearance. Examining and removing tree pests can reduce economic, environmental, and health impacts.

The Next Step

If you notice any of these indicators of tree pests, here are four strategies you may use to gain the upper hand in a controlled environment.

Premedicate Your Actions

Damage caused by pests is usually only superficial. A pest may cause ragged or spotty leaves for a period, but if environmental factors shift, the pest may disappear. The injured leaves will fall off, and the plant will recover. A balanced ecosystem allows for this to happen.

Get creative with your plant selection. 

Specific families of plants are often the target of pests. If you plant a variety of species, any pest damage or tree disease that does develop is more likely to be contained in a small area rather than the entire landscape.

Conclusion 

Trees are vital for the ecosystem's health, providing air, cooling, and housing various animal species. However, they can be severely damaged by various pests, including insects, caterpillars, aphids, scale insects, and mites. Insects, such as beetles, caterpillars, aphids, scale insects, and mites, can eat plant matter and spread diseases. Common tree pests include fungi, which cause diseases like anthracnose, powdery mildew, and Dutch elm disease, while bacteria cause wilting, color changes, and cankers. Viruses can cause abnormal growth and color changes. Defoliators, such as spiders and rust mites, can also cause damage to trees. Therefore, it is essential to identify, prevent, and control these pests to maintain the health of our ecosystem.

The gipsy moth, a pest responsible for defoliation in over a million forest acres since 1980, lay hundreds of eggs on newly emerging leaves each spring, causing severe damage to the foliage. The western tent caterpillar feeds on various trees, particularly fruit trees, willow, poplar, quaking aspen, cottonwood, and others. The Douglas-fir tussock moth attacks Douglas-fir trees and other fir species in urban areas, causing defoliation and damage.

The Emerald Ash Borer destroys millions of ash trees annually, causing top-to-bottom crown dieback and leaf yellowing. The Asian Longhorn Beetle/Borer, discovered in Brooklyn in the late 1990s, can cause leaf yellowing or drooping and sawdust accumulation at the tree's base. Bark beetles cause damage to hardwoods and conifers, with infectious diseases causing the most damage

Sap-sucking insects like aphids, scale insects, and Balsam Wooly Adelgids can cause yellowing leaves, branch dieback, and even tree death. Infected trees should be treated during the final weeks of winter to prevent their return in the spring

The Black Turpentine Beetle, an invasive insect, targets Southern pines, especially those exploited for naval stores or timber production. It has been shown to attack damaged and healthy urban pine trees

Pest control for trees involves preventing pests from infesting them. Cultural methods, such as selecting trees that thrive in your climate, regularly removing diseased or broken branches, and watering them regularly, can increase resistance to pests. Chemical methods, such as pesticides and fungicides, may be necessary if cultural measures are insufficient. Biological control involves using natural parasites and predators, such as ladybirds and lacewings, to reduce tree-damaging pests

Tree pests can have significant environmental, economic, and human health impacts. They disrupt ecosystems, disrupt food webs, and disrupt food webs. Economically, they can damage crops, lower timber prices, and create trade barriers. Human health risks include Lyme disease and respiratory issues. Tree pests can also reduce the beauty of landscapes and wilderness places.

To control tree pests, premedicate actions, which involve removing damaged leaves and allowing the pest to disappear. Using a variety of plant species can help contain pest damage or tree diseases in small areas. By implementing these strategies, you can protect your trees and maintain their health.

Content Summary: 

• Trees are crucial to the health of our ecosystem.
• They also serve as homes for many different species of animals.
• Pests can majorly impact the health of trees and the surrounding ecosystem.
• Various tree pests are covered in this handbook, along with their identification, prevention, and control.
• One of the most widespread causes of tree damage is caused by insects.
• Green peach aphids and woolly aphids are two examples of common tree aphids.
• Spider and rust mites are only two examples of the many kinds of tree mites.
• Tomato spotted wilt virus and apple mosaic virus are two common tree viruses.
• Since 1980, the gipsy moth has been responsible for the annual defoliation of over a million forest acres.
• Western tent caterpillar infestations start with shrivelled or brown leaves and defoliation on the top and exterior branches.
• In urban areas, the Douglas-fir tussock moth is not limited to attacking Douglas-fir trees; it can also target blue spruce and other fir species.
• The tussock moth is notoriously persistent.
• Each year, the emerald ash borer destroys millions of ash trees.
• Asian longhorn beetles can cause leaf yellowing or drooping and sawdust accumulation at the tree's base.
• Bark beetles come in a variety of species and can cause damage to both hardwoods and conifers.
• Conifers with reddish-brown needles radiating from the crown downward or deciduous trees with brown or white pitch tubes on the exterior of the bark are both symptoms of bark beetle infestation.
• Keep your eyes peeled for these potentially fatal insects right now.
• Before it's too late, consult a local arborist if you notice any of the indicators above of insect infestation, including the peculiar yellowing or premature drop of leaves on your tree.
• Adelgids are soft-bodied aphids with piercing-sucking mouthparts that only feed on coniferous trees.
• Hemlocks fall prey to the Hemlock Woolly Adelgid, whereas firs are the target of the Balsam Woolly Adelgid.
• The best method to protect your trees and keep them healthy is to stop pests from ever infesting them in the first place.
• Some strategies for warding off tree pests are listed below.
• By taking appropriate care of your trees, you can increase their resistance to pests, which can be achieved through cultural means.
• Irrigation: Keep your trees healthy and robust by watering them regularly.
• Some chemical approaches are listed below: Pesticides: If insects eat or destroy your trees, you can use pesticides to stop them.
• Using parasites and predators found in nature is at the heart of biological control for tree pests.
• Some examples of biological ways of control are: Natural predators, such as ladybirds and lacewings, can be introduced to help reduce tree-damaging pests.
• Pheromone traps can entice pests away from your trees, where they will be trapped.
• Combining these methods can keep your trees healthy and pest-free.
• Insects and other pests that feed on trees can seriously affect ecosystems, economies, and human health.
• Insects, fungi, and bacteria are some of the most common tree pests, and they may damage trees and other plants.
• Some ways in which tree pests harm ecosystems, economies, and people are outlined below.
• There are many ways in which tree pests can upset the natural order of things.
• In addition to reducing biodiversity, pests can damage trees, leaving them open to attack from additional pests and diseases.
• Some insect pests of trees can be dangerous to people.
• Tree pests not only have these other negative effects but can also reduce the beauty of landscapes and wilderness places by damaging the trees' appearance.
• Examining and removing tree pests can reduce economic, environmental, and health impacts.
• If you notice any of these indicators of tree pests, here are four strategies you may use to gain the upper hand in a controlled environment.
• Damage caused by pests is usually only superficial.
• A balanced ecosystem allows for this to happen.
• Get creative with your plant selection.
• Specific families of plants are often the target of pests.