Western Yellowjacket - School IPM - USU Extension

    Western Yellowjacket

    Vespula pensylvanica

    Wasps Fact Sheet: English, Spanish.

    Yellowjacket

    Yellowjacket (Eugene Zelenko, Wikimedia Commons)

    Yellowjacket

    Yellowjacket nest (Whitney Cranshaw, Colorado State University, Bugwood.org)

    Yellowjacket

    Yellowjackets (Whitney Cranshaw, Colorado State University, Bugwood.org)

    Identification

    • 3/8 - 5/8 inch long
    • yellow and black; no hairs
    • abdomen is blunt on the anterior side

    Nesting Habits

    • social
    • colony dies off every fall; fertilized queens overwinter
    • nest in old rodent burrows, holes, structural voids, etc.
    • queens start new every spring; colonies grow throughout the summer months

    Diet

    • insects, nectar
    • scavengers (meat, sugar, human food, etc.)

    Significance

    • nests pose a serious health risk to humans
    • scavenge in fall making outdoor events dangerous

    IPM Recommendations

    • Monitor for yellowjacket nests early summer - fall.
    • Purchase and use a bee veil, suit and gloves.
    • Minimize nesting habitat around property by caving in old rodent burrows and sealing exterior cracks and crevices, holes in trees, wall voids, etc.
    • Install tight-fitting screens in windows.
    • Never plug entrance holes to nests!
    • Use a wet-vac to vacuum yellowjackets, then dig up nest. This technique can be dangerous if not done properly. Research the proper technique and always wear protective gear. Do not attempt while people are present.
    • Apply a non-repellent insecticidal dust in and immediately around entrance hole(s) at night.
    • Consider outsourcing yellowjacket management.

    Additional Resources

    Yellowjackets, Hornets and Paper Wasps fact sheet

    IPM for Stinging Bees and Wasps: Integrated Pest Management in Sensitive Environments (University of Nebraska-Lincoln Extension)