Yellowjackets (Vespidae) can be much more than a nuisance. They exhibit territorial behavior and can sting multiple times. This makes them especially dangerous to people who suffer from anaphylaxis, a potentially life-threatening allergic reaction to being stung.
Yellowjackets create a new colony each year, starting from a single mated female that survived the previous winter. Fertilized queens begin emerging in April and early May to build a small nest and start laying eggs. Preferred nest sites tend to be natural cavities such as abandoned animal burrows or tree holes. Still, yellowjackets are opportunistic and will readily build nests in wall voids, attics or similar locations.
After a few weeks, the first workers emerge to take over nest management and colony defense. From there, the colony grows quickly, reaching up to 5,000 adults by August and late September. Colony numbers decline rapidly as temperatures start to drop in the fall. Eventually, new queens and males (known as drones) are produced; they leave the nest to mate, and the now-fertilized queens find a new place to overwinter. The rest of the colony dies off, and the lifecycle repeats the following spring.
As is the case with any flying insects, preventing yellowjackets from accessing a property is virtually impossible. But you can take a few proactive steps throughout the spring and summer to help protect your clients against these painful pests.
First, look for solitary yellowjacket queens at the first signs of spring. Don’t be quick to dismiss reports of flying insect activity inside the house on cold spring days. Locating and eliminating these mated queens before they can establish a nest is a good way to avoid bigger issues later in the year.
Also, as temperatures warm up, educate your clients on the importance of keeping trash cans covered and food protected when eating outdoors. These attractive resources will encourage hungry yellowjackets to frequent the property in search of their next meal or future nesting site.
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About the Author
Dr. Bentley is VP of training and technical services for the National Pest Management Association. You can reach him at mbentley@pestworld.org.
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