What Are Hackberry Gnats and How to Get Rid of Them?
These harmless seasonal insects swarm homes seeking shelter. Effective control relies on physical removal and sealing entry points, not chemical treatments.
Swarms of tiny insects on window screens or inside the home are often hackberry gnats, also known as hackberry psyllids. These pests are a common, recurring issue for many homeowners. Their appearance in large numbers is a temporary, seasonal issue.
Understanding Hackberry Gnats
These small, dark, winged insects are not gnats but a type of insect called a psyllid. They resemble miniature cicadas and are only about 3/16 of an inch long. Their life cycle is dependent on hackberry trees, where adults lay eggs on new leaves in the spring. The feeding of young psyllids causes the leaf to form small, raised bumps known as galls, which serve as a protective nursery.
These galls are cosmetic and do not harm the overall health of the hackberry tree. The insects that emerge are nuisance pests; they do not bite, sting, or transmit diseases to humans or pets. Similarly, they pose no threat to your home, furniture, or indoor plants, as their only food source is the hackberry leaf.
Why Hackberry Gnats Invade Homes
The transition from a harmless insect on a tree to a home invader is driven by seasonal changes. In the late summer and fall, as temperatures cool, adult psyllids emerge from their galls on the hackberry leaves. They then seek out sheltered places to survive the winter.
Your home presents an ideal overwintering site, attracting them with its warmth and light. They are drawn to light-colored siding and exterior lights left on at night, which guide them toward tiny entry points. Because of their small size, they can pass through standard window screens or slip through small cracks and crevices around the building’s exterior. A secondary period of activity can occur in the spring when warming temperatures prompt overwintering gnats to become active again.
Managing a Hackberry Gnat Infestation
When faced with an active infestation inside your home, physical removal is the most practical approach. The most effective tool for clearing them from windows, sills, and walls is a vacuum cleaner with a hose attachment. This method quickly reduces their numbers without using chemicals. Sticky traps can catch some insects but are less efficient than vacuuming for a widespread problem.
Insects that have found their way inside are typically doomed by the dry indoor environment and will die off naturally. For this reason, using indoor insecticide sprays is not recommended as they are often ineffective and can create an unnecessary mess. Outdoors, a simple strategy is to reduce exterior lighting near entrances at night to make your home a less attractive target.
Long-Term Prevention Strategies
Preventing future infestations relies on exclusion, which means sealing the pathways they use to get inside. A thorough inspection of your home’s exterior is the starting point. Pay close attention to areas around window frames, door sweeps, and any entry points for utility lines, sealing any visible cracks or gaps with a sealant. Damaged or torn window and door screens should be repaired or replaced.
Some homeowners consider managing the hackberry trees on their property, but this is rarely a practical solution. Spraying large trees is often costly and has limited effectiveness in controlling the adult psyllid population. Focusing on securing the building envelope provides a more reliable and lasting defense against these seasonal invaders.