As the trees begin to show their autumn hues and squirrels rush to stash away their bounty, a few creatures in the garden are looking for good winter homes.

Hackberry psyllids, also known as hackberry nipplegall makers, are tiny winged insects that join the ranks of spiders, wasps, houseflies, multicolored Asian lady beetles, and boxelder bugs when it comes to believing your house is their house in autumn.

Hackberry psyllids are small enough to fit through average window and door screens, but large enough to be distinguishable to the naked eye. Adults are typically 2 to 3 millimeters long and a half millimeter wide, making them extremely difficult to keep out. The insects are most commonly noticed congregating in windowsills and doorways, hopping their way to shelter.

Fortunately, hackberry psyllids are harmless to humans, pets and plants other than hackberry trees. The easiest method of dealing with them is to simply vacuum them from the spaces where they collect. Use a smaller mesh screen or keep windows and doors closed once the insects are observed.

Caulk and seal foundation cracks, siding seams and any other openings where insects could enter your home as much as possible.

If hackberry psyllids become a regular major nuisance in your home, the next step is to consider removing the nearby hackberry tree(s). Hackberries are prone to a number of insect and disease pests, including internal decay that can turn them into hazard trees, so replacing them with a disease-resistant species is a good option for multiple reasons.

Hackberry psyllids have a one-year life cycle. Adults who survive winter lay eggs on the undersides of hackberry leaves as the leaves emerge in spring. Like many insects, adults die after laying eggs. Hatching nymphs feed on leaf tissue. Through an interaction that is still a bit of a mystery to scientists, leaves form a mass of tissue around the nymphs known as a gall. There are many types of galls, but this particular one is shaped like a nipple and is thus referred to as the hackberry nipple gall.

The leaf tissue surrounding the feeding nymph protects it from predators and insecticides. Fortunately, psyllid nymph feeding and galls are only a cosmetic problem to the tree. By the end of the summer, the psyllid will drop from the nipple gall to the ground and complete final transformation into a hopping, winged adult.

Using tight screens and sealing cracks and crevices on your home’s exterior can help to eliminate and exclude other invading insect pests as well.

— Jennifer Smith is a former horticulture extension agent for K-State Research and Extension and horticulturist for Lawrence Parks and Recreation. She is the host of “The Garden Show” and has been a gardener since childhood. Send your gardening questions and feedback to Lawrence Living@ljworld.com.