Tips and Tricks: Treating large yellowjackets, other large nest builders

By Dr. Dina Richman
Product Development Manager, FMC Professional Solutions

For most people, a bee, ant or wasp sting is a minor nuisance — something that can happen when you are enjoying the great outdoors. For some, a more serious situation can occur because of an allergic reaction to the sting or toxin in the venom. Still, only a handful of the thousands of stinging insects are harmful to humans.

Stinging insects are included in the order Hymenoptera, which is comprised of wasps, bees and ants. Most stinging insect pests are social in behavior. In addition, most have a breeding female, and single or multiple generations of non-breeding females, all of which have specific duties.

When pest management professionals (PMPs) get a call to treat a large nest builder, such as a yellowjacket, it is sometimes necessary to treat the nest at night with either dusts or liquids. But PMPs can treat during the day — if they are very careful. Sometimes, liquid treatments do not reach the queen and the colony survives. Applying dust at the entrance of the nest will facilitate movement of product into the colony, eventually killing the queen.

Nests that are located in foundations or voids are more complicated to treat. PMPs will usually need to drill holes through the foundation to reach the nest, and fill the void with foam containing an active ingredient designed to transfer from one insect to the next.

Regardless of stinging insect species, the ultimate target is the queen. Application methods intended to eradicate the queen will prove more effective than methods targeting workers. When using aerosol treatments, spray the nest fully to immobilize individual workers as much as possible. Wait several minutes for a needed retreatment.

Invasive pest species with large populations, such as red imported fire ants, can be treated with liquids and granules. But PMPs should keep in mind that eradication of such pests is not likely, and should customize their treatment methods for continual population suppression.

Finally, beneficial species that pollinate plants, such as honey bees, can be harassed with water, forcing them to find another location. Always keep in mind that when the queen dies, the colony dies, and when the queen moves, so will the colony.