Top 6 Tree Pests Affecting North Phoenix Trees

An Asian longhorned beetle with its distinctive black body with white spots in a North Phoenix garden.

The scorching Arizona sun and dry climate present unique challenges for our beloved trees. Not only do they battle the relentless elements, but they’re also susceptible to a whole lot of creepy crawlies that can wreak havoc on their health.

To keep your trees thriving and looking their best, we put together a guide on how to identify common tree pests in North Phoenix, learn about the damage they can cause, and the preventative measures you can take to protect your landscape from these destructive creatures.

Key Takeaways:

  • Bark beetles, defoliators, sap-sucking insects, wood-boring beetles, and bud and shoot insects make up the diverse range of tree pests that threaten the health of trees in North Phoenix.
  • Early warning signs of a tree pest infestation include yellowing leaves, abnormal growth, visible pests, and sticky sap.
  • The six most common tree pests in North Phoenix right now are Mediterranean pine engravers, bagworms, fall webworms, aphids, spider mites, and Asian longhorned beetles.
  • Help protect your trees from common pests with regular tree care like proper watering, fertilization, pruning, and reducing stress.

5 Different Ways Insects Harm Trees

The problem with tree pests is that they can cause a variety of damage to trees, from weakened branches and stunted growth to complete defoliation and even death. We categorize tree pests based on their feeding habits. This includes:

  • Bark Beetles: Bark beetles are tiny insects that burrow into the bark of weak or distressed trees, bore holes in the bark, and chew on the layer just under the bark, which is called the cambium layer. When beetles enter a tree, they bring with them a blue stain fungus that eventually blocks the tree’s ability to transport water and nutrients.
  • Defoliating Insects: Defoliating insects feed on the leaves of trees, causing them to lose their foliage. This can weaken trees, reduce their ability to photosynthesize, and make them more susceptible to other pests and diseases.
  • Sap-Sucking Insects: Sap-sucking insects pierce plant tissues and extract sap, draining the tree of essential nutrients. This can weaken trees, stunt their growth, and transmit plant diseases.
  • Wood-Boring Beetles: Wood-boring beetles bore into the wood of trees, creating tunnels that can weaken the tree’s structural integrity. This can cause trees to become unstable and may eventually lead to the death of the tree.
  • Bud and Shoot Insects: Bud and shoot insects attack the young growth of trees, including buds, shoots, and leaves. This can stunt the growth of trees, reduce their aesthetic value, and make them more susceptible to other pests and diseases.

Signs of a Tree Pest Infestation

Identifying the early signs of a pest infestation helps your trees receive the necessary treatment and also helps prevent further damage to the rest of your landscape. Here are some common indicators to watch out for:

  • Yellowing, browning, or wilting leaves
  • Stunted growth, distorted leaves, or unusual branch dieback
  • Visible signs of pests, such as insects, webs, or eggs
  • Sticky sap or honeydew
  • Holes or tunnels in the bark
  • Small, dark pellets that may be insect droppings
  • Small piles of what appears to be sawdust, which is known as frass
  • Branches that are brittle, discolored, or have unusual cankers

6 Common Tree Pests Harming Your Trees

Close up image of a mediterranean pine engraver beetle in bark with a maze of tunnels surrounding it.

William M. Ciesla, Forest Health Management International, Bugwood.org

1. Mediterranean Pine Engraver

The Mediterranean pine engraver is a non-native bark beetle that poses a significant threat to urban pine trees.  Like other bark beetles, the Mediterranean pine engraver attacks stressed trees by boring into the bark and feeding on the outer layers of the tree, limiting the tree’s ability to transport water and nutrients.

Treatment

To help control the spread of infestation among pine trees, a Certified Arborist may recommend removing heavily infested trees, applying insecticides, or using pheromone traps to disrupt the beetles’ mating cycle.

Close-up of a bagworm, a brown, bag-shaped insect hanging from a tree branch in a phoenix yard.

Left image: Mary C Legg, Mary C Legg, Bugwood.org; Right: a close-up of a bagworm crawling with its wooden bag.

2. Bagworm

Bagworms are caterpillars that create bags around themselves. They feed on the leaves and needles of trees, causing defoliation and weakening the tree’s overall health. Infested trees may have unsightly bags hanging from their branches, and their foliage may be sparse or completely stripped.

Treatment

Bagworms can be removed manually from trees, especially during the early stages of infestation. Insecticides can also be used to control the population.

Close-up of a tree branch with leaves completely devoured and surrounded by webs and small worms.

3. Fall Webworm

Fall webworms are caterpillars that create large, unsightly webs in tree branches in the fall. They feed on the leaves of trees, causing defoliation, and weakening the tree’s structure. While fall webworms are not typically a serious threat to healthy trees, they can be unsightly and may require treatment to protect ornamental trees.

Treatment

Fall webworms can be removed manually by destroying their webs. Insecticides can also be used to control the population, especially during the early stages of infestation.

Close-up of the underside of a leaf with clusters of green aphids, a clear sign of an aphid infestation.

4. Aphids

Aphids are small, sap-sucking insects that can infest various trees, including fruit trees. They feed on the leaves and stems of trees, causing yellowing, curling, and stunted growth. Aphids produce a sticky substance called honeydew that is often found on leaves. This honeydew can attract ants and may also collect fungal spores that cause sooty mold growth and further deterioration of the tree.

Treatment

Aphids can be controlled using insecticidal soap, neem oil, or other organic insecticides. Ladybugs and lacewings are natural predators of aphids and can help to control populations.

Close-up of a spider mite on the underside of a leaf, surrounded by small, dark pellets (frass) and larvae.

5. Spider Mites

Spider mites are tiny arachnids that attack many different hardwoods, including the palo verde tree. They use their needle-like mouthparts to suck the sap from the leaves, causing them to turn yellow or brown and drop prematurely.

Treatment

Spider mites can be controlled using insecticidal soap, neem oil, or specialized miticides. Ladybugs and lacewings will also naturally rid your trees of spider mites.

Close-up of an asian longhorned beetle on a tree branch. The beetle is black with white spots and has long, black and white antennae.

Gillian Allard, FAO of United Nations, Bugwood.org

6. Asian Longhorned Beetles

The Asian longhorned beetle is a large, black beetle with distinctive white spots and long black and white antennae. It is an invasive pest that poses a serious threat to hardwood trees. This beetle bores into the wood of trees, causing extensive damage and eventually leading to the death of the tree. Infested trees may have large, round exit holes in the bark.

Treatment

If an Asian longhorned beetle infestation is suspected, it is important to contact local authorities immediately. Quarantines and removal of infested trees may be necessary to prevent the spread of this pest.

What You Can Do to Prevent Common Tree Pests from Harming Your Trees

Climate change is significantly impacting the distribution and behavior of tree pests. Rising temperatures, changing precipitation patterns, and more frequent extreme weather events are creating favorable conditions for many pest species to thrive and expand their geographic range. As a result, tree pests are becoming more prevalent and causing greater damage to trees in many regions.

To combat the challenges posed by climate change and tree pests, we must take proactive measures to keep your trees healthy, including:

  • Monitoring for Signs of Infestation: Regularly inspect your trees for signs of a pest infestation. If you notice anything out of the ordinary, call a Certified Arborist as soon as possible.
  • Watering Properly: Ensure your trees receive adequate water, especially during dry periods. Overwatering can also be harmful, so aim for deep, infrequent watering.
  • Fertilization: Provide your trees with essential nutrients through regular fertilization.
  • Pruning: Proper pruning removes dead or dying branches to promote tree health and can improve air circulation and sunlight penetration, reducing the risk of pests and diseases.
  • Reducing Stress: Avoid stressing your trees by avoiding excessive pruning, root damage, or salt buildup from underwatering.

Call Titan Tree Care for Expert Tree Pest Control

If you suspect a tree pest infestation or have questions about tree care, don’t hesitate to reach out to Titan Tree Care. Our team can provide accurate diagnoses, effective treatments, and valuable advice to protect your trees.

Call us today at 623-444-8448 to schedule a consultation.

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Titan Tree Care is a full-service tree care company located in Anthem, AZ and serving all of North Phoenix. We offer a wide range of services to meet your tree care needs, including tree and palm trimming, tree pruning, tree removal, stump grinding, and more. We also offer insect or disease treatments and fertilization services. We are dedicated to providing high-quality, safe, and effective tree care services to our customers and work hard to ensure that your trees are healthy and look their best.