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Wasps and Bees

By Carl Wilson,Denver County horticulture agent with Colorado State University Cooperative Extension

Wasps and bees too near human activities spell inevitable conflicts. Yellowjackets cause almost all bee stings and are common picnic pests in late summer. In balance, though, these insects are beneficial as predators of pest insects. In their late-season scavenging, they will tackle insects as large as caterpillars. Banded yellow and black yellowjackets nest underground. They may fly as far as 1,000 yards from the colony, so often the nest is difficult to locate.

Nest destruction is the best control when nests are too close to homes or other areas of human activity. If nests must be destroyed, follow these steps:

  • Use an aerosol "wasp and hornet" product with a jet spray
  • Go outdoors with the spray and a flashlight after dusk when the adult yellowjackets are in the nest. Defenders are less likely to emerge at this time of day.
  • Spray the nest entrance. In most cases, a single application should destroy the colony although some newly emerged wasps may be seen for up to a week later.
  • If nests are further away and yellowjackets visit only at picnic time, consider preserving them as part of the balance of nature.

Photograph courtesy of Judy Sedbrook.

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Date last revised: 01/05/2010