Household and Houseplant Insects

Late February to early March is just about the right timing for household and houseplant insects to show up. Over-wintering outdoor insects in the home become indoor household nuisance pests, and new insects may just be waking up. Plus, houseplants that survived the move in from the patio last fall will typically harbor insects in small numbers that now could be exploding with increasing numbers.

Household nuisance insects include boxelder bugs, stinkbugs, and Asian ladybugs for sure. Others might be those insects from our houseplants that could not survive indoors and were found dead on the windowsills. All of the nuisance pests can be collected in paper towels or vacuumed up. The boxelder bug will leave behind these small dark spots on the wall and curtains as reminders that "they were there." Dead houseplant insects could be pill bugs, centipedes and other insects that have resided in the soil inside a pot.

One visitor that just showed up or could be coming soon is the ant. They have begun to wake up for the season and without being able to be outside, have found their way inside the home. As warmer weather comes along, ants will disappear. If, however, you have pet food available, ants can be persistent. Move the food to a new spot, pick the bowl up for the night and use soap and water to remove their "trails."

Houseplant insects that are still alive and increasing in numbers could be aphids, spider mites or soft scale insects. Aphids and scale insects can cause the houseplants to look shiny and sticky. Spider mites can cause some stickiness, yet, are more known for their webbing, discoloration, and distortion of foliage, especially young leaves and leaflets.

Aphids are the easiest to control. Use the kitchen sink sprayer to rinse them off along with the stickiness. Bigger houseplants may need to "take a shower" instead. Since the spider mites will have multiple stages of adults and eggs, the above method works, but will need to be repeated, as eggs will continue to hatch in coming weeks. Scale insects will the hardest to manage as adults are securely attached to stems, leaf petioles and even on roots at the crown of the plant. The water treatment works on the younger stages without the protective layer, yet the adult scales will need to be treated with an appropriate insecticide. Adult treatments should occur in the garage if heated with good air circulation or will have to wait until the plants return outdoors. Always read and follow label instructions.

About the author: Richard Hentschel’s expertise extends across several subject areas with specialties in lawn care, fruit tree production, woody ornamentals, and home and community gardening. During his 45-year career in horticulture and agriculture, Hentschel became a well-known and respected expert for commercial and homeowner audiences, industry organizations, and media. He retired from University of Illinois Extension in April 2022 with nearly 30 years of service as a Horticulture Specialist and Educator in northern Illinois.