We have had more phone calls than normal this fall about yellowjacket wasps. Many callers are concerned that they have "bees" and want to know how to save the pollinators. Deciding the desired course of action in this situation requires we take a step back (literally and figuratively) and make a confirmed diagnosis.
Diagnosis starts with a simple question: What color are the “bees" followed by, Are the "bees" coming from a hole in the ground.
Recent experience suggests that approximately 90% of the inquiries we receive about “bees” in the ground or in a house wall are not bees, but rather are yellowjacket wasps.
The difference between honey bees and yellowjackets is easiest to determine by color (they are the same size and shape and behave similarly). Yellowjackets are bright yellow with black markings and shiny. Honey bees are golden brown and fuzzy. Honey bees never nest in the ground. See photo below.
Yellowjacket wasp colonies are annual – they start from scratch every spring and do NOT reuse an old nest. The new females produced in the fall of the year are able to hibernate after mating. All other members of the original nest – the old queen, the workers and the males -- will die when it freezes.
Yellowjackets are not effective pollinators but they are beneficial. Yellowjackets feed on other insects during the summer and are a beneficial predator. This benefit diminishes by late summer as the queen stops laying eggs and the colony stops collecting insects to feed to her larvae. Wasps can be controlled in late summer with little effect on the ecosystem (unlike honey bees which have perpetual colonies that persist from year to year in the same location).
There are two options for yellowjacket control: One is to do nothing and wait for the colony to die in early winter. Cheap and easy, but the down-side is you have to put up with the risk of being stung until the weather gets colder.
The second option is to apply insecticide dust or foaming wasp and hornet aerosol spray into the nest opening at night. There is very little chance of being stung at night, when the wasps are not active. Insecticide dust and foaming aerosol should be more effective than a liquid spray that will mostly soak into the ground or concrete. The aerosol foams appear to be as effective as insecticide dusts in penetrating into the nest area for good control. It still may take more than one treatment to eliminate the colony, especially in those situations where the colony is above or below, or “around the corner” from the visible opening.
See the Yellowjacket Page on the Plant & Insect Diagnostic Clinic website for more details.
Yellowjacket wasps are shiny, bright yellow and black; Honey bees are fuzzy and golden brown.
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