FMC Professional Solutions: Stinging Insects

By Dr. Dina Richman, Product Development Manager

For all stinging species, the ultimate target is the queen. Application methods intended to eradicate “her highness” will prove more effective than methods targeting workers.

Stinging insects are included in the order Hymenoptera, which comprises wasps, bees and ants. Most are social in behavior, with a breeding female (“the queen”) and single or multiple generations of non-breeding females, all of which have specific duties. Nests can vary from a few dozen insects to thousands.

When pest management professionals (PMPs) get a customer call to treat a large nest builder, such as yellowjackets, it is sometimes necessary to treat the nest in the evening or at night with either dusts or liquids. At night, the insects are in the nest and less active; try for 45 minutes after sunset or later.

PMPs can treat during the day, if they are very careful. Don’t stand directly under the nests, as insects will drop out as you spray. 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. This will also ensure that any insects not “at home” will come in contact with insecticide when they return. Always keep in mind that when the queen dies, the colony dies, and when the queen moves, so will the colony.

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.

When using aerosol treatments, spray the nest fully to immobilize individual workers as much as possible. Wait several minutes for a needed re-treatment.

Invasive pest species with large populations, such as red imported fire ants, can be treated with liquids or granules, and both can be applied as a mound treatment or a broadcast treatment. To increase the speed of control, water in the granules, which need moisture to release the active ingredient. PMPs should keep in mind that complete eradication of such pests is not likely, and should customize their treatment timing for continual population suppression.

Finally, beneficial species that pollinate plants, such as honeybees, can be harassed with water, forcing them to find another location.