Wasps

Wasps

Ichneumonidae

Polistes wasp
Polistes wasps are not aggressive, and rarely sting unless provoked.

A nest usually consists only of a fertilized female and her 8-12 offspring, who abandon the nest not long after hatching. They may build their nests in the open, in a crack or crevice, or inside an attic or crawlspace. They are susceptible to most insecticides, either sprayed on the nest itself or on the cracks and crevices where the wasps come and go.

Frequently, there may be as many as two or even three generations of Polistes wasps produced each season (spring through fall). Most buildings have a few nests; some have many nests. An exterior insecticide treatment under the eaves and of the various cracks and crevices on the exterior goes a long way towards reducing their numbers, as long as the treatment is repeated at the lifetime of the chemical used.

Mud dauber wasp
Mud daubers are a long, slender wasp, usually black with some orange or yellow. They have a definite “wasp waist” – a filament connecting the thorax and abdomen. They can sting, but are not aggressive and rarely do so unless handled.

Mud daubers are solitary wasps. Each fertilized female builds a small nest out of gathered mud, which is attached to an exterior surface, or in an attic, crawlspace or other enclosed area. She lays 8-12 eggs in the nest, which become larvae and then pupate in the nest, emerging the following spring or summer. The nest looks like a mud tube, usually about 1 inch wide by about 2-3 inches long. If the nest has holes in it, the new wasps have already emerged and flown away.

Mud daubers may be treated with a residual spray and then scraped or knocked off. Preventative treatments are usually effective if repeated at the lifetime of the product used.