Carol O'Meara - Colorado State University Extension

Carol O’Meara – Colorado State University Extension

BOULDER COUNTY – With the warm beginning to spring, wasp queens are awakening, shrugging off a winter’s sleep with conquest on their minds. Emerging from their winter’s sleep, queens are foraging for food, a nesting location and materials to begin building it.

Yellow jackets are a major nuisance later in the year when their numbers swell into the hundreds per nest, and to keep your yard from the black and yellow bullies, control starts now, in early spring. In winter, yellow jacket colonies die, leaving only queens. They emerge when the weather warms in spring to begin colonization of our landscapes.

Put out your wasp traps now, filled with heptyl butyrate, or design your own with chunks of cantaloupe – all it takes is a 2-liter sized pop bottle. Cut the top off the bottle at the shoulders, turn it around and slide it into to the lower part of the bottle so the neck points inwards, and staple this together. Before you fit the top on, fill the bottle with a small amount of cantaloupe. Some wasps prefer protein, so make another trap and put a bit of lunch meat in it. Hang these away from your house.

Another wasp that’s becoming active is the European Paper wasp, Polistes dominulus. A rust-and-yellow striped insect, they build open-faced nests up in the eaves, inside sheds, and in other spots located above ground. They aren’t aggressive unless you get too close to the nest; if you do, then they may sting.

Paper wasps look a lot like yellow jackets but aren’t attracted to traps at all. They’re predators, hunting the yard for soft-bodied insects. Other hunting wasps, such as the leafhopper hunting wasp (Pseneo punctatus), are active as well. Their bodies are usually slender with a long, thin constriction from thorax to abdomen. Constructing nests in soil or the hollow pitch of plants, hunting wasps are beneficial insects that stuff their prey into chambers as food for their young to feed upon.

If you shudder at the thought of all these wasps flying around your yard, relax. Hunting wasps don’t bother people or pets unless they feel hassled or threatened. But yellow jackets are a different problem; they aggressively sting and it’s difficult to tell them apart from the European Paper wasp so give them some room.

By Carol O’Meara,
Colorado State University Extension, Boulder County
Colorado State University Extension, together with Boulder County Parks and Open Space, provides unbiased, research-based information about consumer and family issues, horticulture, natural resources, agriculture and 4-H youth development. For more information contact Extension at the Boulder County Fairgrounds, 9595 Nelson Rd., Box B, Longmont, 303.678.6238, e-mail [email protected] or visit