With the unusually dry weather we’ve had in Wisconsin this year, I would not have predicted that springtails (Collembola), would have been one of the commonest samples at the UW Insect Diagnostic Lab this summer. In general, springtails tend to thrive under damp conditions. These tiny (<1/10 inch long), insect-like creatures are commonly associated with leaf litter, rich soil, compost, and mulch or plant beds outdoors where they feed on fungi and decaying plant materials.

Springtails are ubiquitous and can be found around the globe under a wide variety of conditions. In many parts of North America, you can even bump into large numbers of dark-colored springtails (snow fleas) bouncing around on the snow in winter.  Springtails are a fairly diverse group with over 15 Families in North America, so there’s a lot of variability in terms of the color and overall appearance.

Indoors, it’s usually too dry for springtails to survive or reproduce unless damp conditions exist. Occasionally, they can be found indoors in association with overwatered houseplants, new construction (due to residual moisture in construction materials), plumbing leaks, and other moisture issues. In many cases, when springtails are spotted indoors, they originated outside and simply snuck in but perish shortly thereafter due to desiccation.

With the lack of precipitation and this year, I haven’t gotten the impression that springtails are necessarily thriving outdoors. However, the hot and dry conditions are likely forcing springtails to sneak into structures or other spots that may be slightly damper, darker, and cooler. When they do make it inside, springtails are often spotted near moisture sources—kitchen or bathroom sinks, showers or bathtub drains, and basement floor drains. Some good news is that springtails are completely harmless to humans, pets and homes, and in most cases won’t survive long.

The following tips can be helpful when springtails are a problem indoors:

• Monitor both indoors and outdoors—Visually inspect for areas with lots of springtails and see if potential entrance points into structures are nearby. Indoors, glue board traps from the hardware store or garden center can be helpful tools for monitoring and management.
• Manage vegetation near the foundation of homes and other structures—Plants near a foundation can hold in moisture and create good habitat for springtails, spiders, millipedes, and insects that can wander indoors. Having a gap of 1-2 feet or more between a structure and plants increases airflow and can decrease humidity.
• Avoid excessive mulch—A thick layer of mulch can hold in moisture and may create good habitat for springtails and other arthropods.
• Physical exclusion—Sealing up potential entrance points into a structure can help with many pests, including springtails. Caulk and expanding insulation foam can be helpful in this regard. Inspect and replace weather stripping to make sure that windows and doors seal properly. Pay particular attention to high priority areas such as along the foundation, around window and door frames, and basement window wells.
• Keep indoor humidity low—Running a dehumidifier and/or air conditioning can help decrease moisture and make it harder for springtails to survive. Repair or correct any drainage, plumbing, or moisture issues that may be increasing humidity levels within a structure. Allow houseplants to dry out between waterings; soil that is kept damp can be a potential hangout for springtails indoors.
• Insecticides—Since springtails sneaking in from outside don’t survive long, spraying indoors is generally not warranted or helpful. If springtails are highly problematic, treating cracks and crevices on the exterior of a structure may decrease the number making it inside but won’t eliminate them outright.