Why yellowjackets are most aggressive in fall

Yellowjackets frequently build their nests underground. It's easy to miss the entrance and accidentally disturb the nest, triggering a swarm attack.Sadly, the news stories seem to repeat every September. After a week or so of being back in school, a group of school-age children is outside playing at recess and some of them are stung. Or a woman is harvesting tomatoes from her garden and disturbs an underground yellowjacket nest. Or a dad is cutting the grass, mows over a nest opening, and is stung multiple times.

Why do most yellowjacket stings happen in the fall?

1. Their nests are super-sized. Yellowjackets are already highly defensive of their nests, and will attack any potential or perceived threat by swarming, stinging and biting. They post a guard at the nest entrance who will sound the alarm if an attack is deemed necessary. Yellowjacket nests reach maximum size late in the season. So the sheer size of the nest once fall comes around -- as many as 5,000 yellowjacket workers -- makes their presence much more dangerous. 

In fall, yellowjacket workers are in search of a sugar high for energy and will often go after sweet sodas and fermenting fruit.2. They are HANGRY. Hunger can turn humans cranky and irritable, and in this sense, yellowjackets aren't all that different. Fall is the time that yellowjackets' food sources start drying up and they become desperate. The workers are in search of a sugar high for energy, and will often go after sweet sodas and fermenting fruit. This is why you'll see them around trash cans at the County Fair, or the beverages at your Saturday afternoon tailgate party.

3. They are in survival mode. Yellowjackets in fall are less concerned about nourishment and building materials for the nest, and much more focused on their own survival of the fittest. They are social insects, but that social structure takes a dramatic turn as the season ends. The queen yellowjacket dies at the end of the season, while the new queens emerge and mate with the males. Each of these fertilized queens is on her own and must look for her own place to hunker down for the winter. 

A single yellowjacket or wasp sting can cause a life-threatening reaction in a person who is allergic, so it's important not to neglect stinging insect control in early fall. Use RESCUE!® Yellowjacket Traps or W·H·Y® Traps with fresh attractant (or the RESCUE!® Disposable Yellowjacket Trap, which simply takes water) in your yard to catch yellowjackets when they forage for food, and use the Yellowjacket Repellent GoClip® attached to your clothing when you're on the move. 

Where to buy RESCUE!® Yellowjacket Traps and Repellents