Ants are a frequent sight on trees, especially fruit or ornamental varieties. Their presence often signals an underlying issue with the tree’s health or other pest activity. These insects climb tree trunks to forage for food or establish a nest within compromised wood. Addressing the problem requires understanding the root cause, followed by targeted removal and control methods that prioritize the tree’s well-being.
Identifying the Ant Problem
Determining why ants are using the tree dictates the appropriate removal strategy. Most ants are drawn to trees by honeydew, a sweet, sticky waste product excreted by sap-sucking insects like aphids, scale, and mealybugs. The ants “farm” these pests, protecting them from predators in exchange for the sugary reward. Large, visible trails of ants moving up and down the trunk indicate this symbiotic relationship.
A more serious issue is the presence of carpenter ants, which seek to nest inside the wood rather than forage for food. Unlike termites, carpenter ants do not consume wood but excavate galleries to build colonies, typically targeting decayed or moist wood. Signs of a nesting problem include finding piles of fine, sawdust-like material, known as frass, near the base or in bark crevices. Tapping an infested section of the trunk may produce a hollow sound, indicating internal damage.
Non-Chemical Removal Techniques
For ants foraging for honeydew, installing a physical barrier on the trunk is an effective, non-toxic control method. A sticky band prevents ants from climbing the tree to reach pests in the canopy. To protect the bark, secure a strip of material, such as duct tape or commercial tree wrap, around the trunk before applying a sticky substance like commercial tree banding adhesive or petroleum jelly. Check the barrier every one to two weeks and refresh it to prevent ants from crossing over accumulated debris.
Disrupting ant trails and addressing the honeydew source are important non-chemical tactics. Ants rely on pheromone trails for navigation; wiping visible trails with a solution of water and mild dish soap can disorient them and eliminate the chemical markers. For sap-sucking pests, a strong jet of water from a hose can physically dislodge them from the leaves and branches. Alternatively, spraying affected areas with insecticidal soap or horticultural oil can smother soft-bodied pests like aphids and scale, eliminating the ants’ food source.
Applying Targeted Insecticide Treatments
When ants are nesting within the wood or non-chemical barrier methods fail, a targeted chemical approach may be necessary. The most strategic method involves ant baits, formulated as liquid, gel, or granular materials containing a slow-acting toxin. Worker ants consume the bait and carry it back to the colony to share with the queen and larvae through trophallaxis, which eliminates the entire colony. Placing tamper-resistant bait stations near the tree’s base or along established trails allows safe foraging while minimizing exposure to pets, wildlife, and beneficial insects.
For carpenter ant colonies, insecticidal dusts can be applied directly into nest entrances or galleries found in the trunk. These dusts contain active ingredients like boric acid or diatomaceous earth, which are carried deep into the nest on the ants’ bodies, killing the colony members. Avoid broad-spectrum spraying of the entire tree, as this kills beneficial insects and can repel the ants, preventing them from taking bait or dust back to the colony. Systemic insecticides absorbed by the tree are generally not recommended due to potential non-target effects.
Preventing Future Infestations
Long-term ant control hinges on managing the conditions that initially attract them to the tree. The primary focus is controlling populations of honeydew-producing insects like aphids and scale, which serve as the ants’ main food source. Introducing natural predators, such as ladybugs and lacewings, helps keep these pest populations low, removing the incentive for ants to climb the tree.
Cultural practices are important for reducing ant access and nesting sites. Pruning branches that touch fences, structures, or other vegetation eliminates “ant bridges,” forcing ants to use the treated trunk to reach the canopy. Carpenter ants are drawn to soft, moist wood, so removing any dead, dying, or decaying wood from the tree and surrounding yard eliminates potential nesting locations. Maintaining a healthy tree through proper watering and fertilization makes it less susceptible to the stress that attracts sap-sucking pests.