4 Common Pests That Can Harm Your Trees

Caterpillar with yellow and black markings eating a hole in a green leaf.

Trees in your backyard or garden can add beauty to your outdoor space and provide a natural habitat for birds, insects, and other animals. Unfortunately, some less desirable pests can also wreak havoc on your delicate trees, leading to significant damage if left unchecked. Here is an overview of four common pests that can harm your trees so you can take the necessary steps to protect them.


1. Aphids


Aphids are colonial insects with small, feathery bodies. They range in size from 1/16 to 1/8 of an inch and might be pale green, yellow, grey, or brown. You can distinguish aphids from other tree parasites by their distinctive tail-like hind end.


Large populations can cause ugly deformities in foliage like curling, discoloration, and malformed leaves. In addition, they can secrete copious amounts of honeydew, a viscous material that encourages the growth of sooty mold.


Oaks, pines, fruit trees, poplars, willows, and maples are susceptible to assault from aphids because they rely on the tree's sap for sustenance. Aphids can rapidly multiply to result in hundreds to thousands of adults thanks to their ability to deposit eggs in the fall and have them hatch in the spring.


Aphid infestations also manifest in other ways, such as the death of plant shoots and reduced growth. If you have aphids on your trees, the sticky fluid they secrete could end up all over your lawn furniture or automobile. If you notice these symptoms, it's time to take action to rid your tree of the pests causing harm.


2. Asian Longhorn Beetle


Adult Asian longhorn beetles are black with distinctive white markings and can reach up to 1.5 inches. When female beetles lay their eggs in tree bark, the developing larvae bore into the wood, causing damage to the tree's vascular system. The larvae compromise the tree's structural integrity to the extent of failure.


Discoloration, drooping foliage, pencil-sized holes, sawdust along the trunk, and dust-like frass on the limbs are all possible symptoms of Asian longhorn beetle infestation in trees. To prevent infestation, never transport firewood or other wood products that may be afflicted with this destructive bug over long distances.


3. Gypsy Moth


Gypsy moths lay hundreds of eggs, and the resulting caterpillars feed mostly on elm, oak, maple, and birch trees. Caterpillar larvae can harm and sometimes completely defoliate plants by feeding on their leaves.


The females deposit yellowish and tear-dropped egg clusters on tree trunks. Each mass can contain as many as 500 eggs. The appearance of these eggs in the spring is often the first indication of gypsy moth presence.


Preventative measures include the management or removal of stressed trees and pest breeding grounds and sanitation. In addition, throughout the mothless season, you should employ baited traps to catch adult moths and eliminate all egg masses. 


Conduct routine tree maintenance and watch for pest activity since trees with their leaves repeatedly removed might become stressed and susceptible to attack.


4. Scale Insects


Scale insects suck the sap of trees and other woody vegetation. You can find them on the stems, leaves, and fruits. The strong exoskeleton of a scale insect allows it to bore into the surface of a plant and feed on the phloem. If not treated, this leads to wilting, discoloration of leaves, branch dieback, stunted growth, and possibly plant mortality.


Scale insect infestation will also cause a decline in vitality and will show a significant presence of colonies of sooty mold on different tree components. Homeowners must be on alert for signs of infestation later in the winter so they can take action quickly. You can manage scale infestations with trimming, insecticidal detergents, and horticultural oils.


Contact us at Baumann Tree for arborist services if you notice extensive tree damage after a pest infestation.

August 19, 2026
A tree does not have to be falling over to become a concern. Sometimes the first warning is a branch scraping the roof. Other times, it is a canopy that has grown so thick it overwhelms the yard, a limb hanging above the driveway, or a tree that simply does not look as healthy as it did a few years ago. Knowing when a tree needs attention can help St. Louis property owners address problems before they become much harder to manage. Baumann Tree provides tree service, tree removal, and tree trimming in St. Louis, MO for homeowners and property owners who want to take care of troublesome trees safely and effectively. For professional tree care, call 636-375-2812. When Your Trees Start Competing With Your Property Trees and homes share the same space, and eventually that can create conflicts. A tree that was small when a home was built may now stretch across the roof, crowd a fence, block a driveway, or extend branches toward neighboring property. Mature trees can be one of the best features of a St. Louis yard, but they also require more attention as they grow. Professional tree service in St. Louis, MO can help you determine what needs to be trimmed, what should be monitored, and when removal may be the better long-term solution. Instead of treating every tree the same way, Baumann Tree can evaluate the situation and recommend an appropriate approach for the property. A Tree Doesn't Have to Be Dead to Need Removal Many people associate tree removal with completely dead trees, but there are other reasons a tree may need to come down. Its location may have become problematic, the trunk may have developed structural weakness, storm damage may have compromised major limbs, or the tree may be declining to the point that keeping it creates an unnecessary risk. With tree removal in St. Louis, MO , the surroundings matter just as much as the tree itself. Homes, garages, fences, landscaping, sidewalks, and neighboring properties can all affect how a tree should be removed. Baumann Tree can assess the tree and surrounding area before determining how to approach the job. Warning signs worth paying attention to include a new or increasing lean, large dead sections in the canopy, cracks in major limbs or the trunk, decay, broken branches that remain lodged in the tree, or noticeable changes following severe weather. If a tree on your property has you wondering whether it is still safe to keep, call 636-375-2812 and have Baumann Tree take a closer look. Tree Trimming Is About More Than Making a Tree Look Neat Trimming can dramatically change the appearance of a property, but good tree trimming should accomplish more than creating a tidy canopy. Strategic trimming can remove problematic branches, create clearance around structures, address damaged growth, and help prevent certain limbs from becoming larger concerns later. For example, you may need tree trimming in St. Louis, MO if branches are beginning to hang over your roof, interfere with a driveway or walkway, rub against one another, block visibility, or create too much weight in a particular part of the canopy. The goal is not simply to cut branches back. Trees respond to pruning, which is why knowing which branches to remove—and which ones to leave—is important. Professional trimming helps address the immediate issue while taking the overall tree into consideration. Take Another Look After a St. Louis Storm Take Another Look After a St. Louis Storm Strong winds and thunderstorms can reveal weaknesses that were easy to miss beforehand. After severe weather, take a look at the trees around your home from a safe distance. A branch may be partially broken without falling, the canopy may look noticeably different, or a tree may appear to be leaning more than it did before the storm. Damage high in the canopy can also be difficult to judge from the ground. If something looks different, having it evaluated can be a much better option than waiting to see what happens during the next round of bad weather. Give Your Trees the Attention They Need Call a certified arborist promptly if you notice sudden canopy dieback from the top down, D-shaped holes in ash bark, wilting spreading across connected trees, dark streaking under oak bark, or shepherd's crook tips on ornamental pears or crabapples. Even when symptoms seem minor, a professional inspection is worthwhile. Most tree pests target stressed trees first, making consistent care essential to prevention. Protect Your St. Louis Trees With the Right Help Sometimes a tree needs a few carefully selected branches removed. Sometimes it has reached the point where removal makes more sense. And sometimes you simply need an experienced tree professional to help you figure out which option is right. For tree service, tree removal, and tree trimming in St. Louis, MO, contact Baumann Tree. The team can help you address overgrown, damaged, declining, or inconveniently located trees and keep your property looking its best. Call Baumann Tree at 636-375-2812 today to schedule tree service in St. Louis, MO.
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