By Linda Williams, forest health specialist, Woodruff, Linda.Williams@wisconsin.gov,  920-360-0665

Barklice tend to congregate in large groups on trees, which can lead some people to worry about tree health, but they are actually quite harmless.

Immature barklice congregated on bark. Striped abdomens are easy to see before the insects mature into adults and develop wings.

This insect doesn’t feed on the tree itself but instead on the algae, lichen and other debris that collects on the surface of the bark. Barklice are not considered pests, and treatment is generally unnecessary.

Group of adult barklice with tent-like black wings.

Despite their name, barklice are harmless to people too. They are not a true lice so they don’t bite or carry diseases that would cause concern for human health. Rather than trying to get rid of them, try this playful activity with kids (and adults who are young at heart) instead. When you find a congregation of them, move your hand towards one side of the group and watch as they move in unison to get away from your hand. Congratulations… you’re herding bugs!