You may have noticed more roly-poly bugs in Johnson County this summer — Here’s why

Roly-polies, or pillbugs, like moist, rainy conditions and humidity. The recent rainy spells Johnson County has seen could be contributing to a more active roly-poly population in the area this summer. Image from K-State Entomology Department website

Lately, if you’ve seen more of the small black bugs known as pillbugs — more commonly referred to as “roly-polies” — in Johnson County, you’re not alone.

What’s going on? Like a lot of phenomena noted by readers when it comes to insects and animal life, it has to do with the weather.

  • Dennis Patton, horticulture agent at the K-State Research and Extension Office, said the increase in pillbugs has to do with the spurts of rain Johnson County has seen in recent weeks.
  • Generally, pillbugs like humidity and cooler, rainy conditions.
  • They’re more likely to be seen in the house during rainy parts of spring and fall, when they’re looking for somewhere warm to escape to.
  • This means, even in summer when it’s rainy, there may be more of them in your garden inside your basements, if it’s not well insulated.

What’s the impact? Roly-polies are “decomposers”, Patton said, that mainly feed on decaying organic matter.

  • When roly-poly populations are high and they run out of organic matter to eat, Patton said they often start eating plants, including perennials flowers and garden shrubs.
  • “You’ll see this when things are coming up in the spring or sometimes people put out seedlings in the spring,” he said. “They’ll start devouring the plant healthy plant material.”

When will they go away? Patton said roly-polies prefer rainy weather and humidity to the hot, dry weather that typically arises in July and August.

  • As it gets warmer and drier, he said, we can expect them to go back to hiding from the sun.
  • “They need a moist, humid environment to survive,” He said. “They’re not going to make it out in the boiling hot sun.”

How do you keep them away? Although the heat will likely keep roly-polies outside, there are ways to keep them from getting inside.

  • Spraying insecticide sprays along cracks and crevices of a house’s lower levels can help, as that’s usually where they enter from.
  • Since roly-polies like to eat decomposing things, Patton said keeping decomposing leaves and grass always from the house might also help.
  • Diverting water from gutters or downspouts near the house could also keep away the extra moisture that roly-polies enjoy.