This week we began to receive calls about cicada killer wasps. Cicada killer wasps are large (up to 2 inches long), black and yellow wasps with rusty colored wings. Cicada killer wasps are solitary, only one wasp per nest. The female wasp digs a whole where she lays her eggs on paralyzed cicadas that she catches. Although cicada killers are solitary it is common to find multiple nests in a single area. Cicada killers may look big and scary, but they are a non-aggressive wasp and seldom sting people. In general it is best to leave nests alone, however, removal is justified if a nest is located in a high traffic area (along a sidewalk or near a porch). Ground nests of cicada killers can be destroyed by placing an insecticide dust (e.g., Sevin garden dust) in and around the nest entrance during the night. The dust particles will adhere to the wasps as they come and go from the nest. Cover the nest opening with a shovelful of soil after all activity has stopped.

Finally, we received two reports of Imperial moths around the Iowa State campus in the last week. Imperial moths are a wild silk moth, in the same family as Luna moths and Cecropia moths. Imperial moth caterpillars feed on a variety of hardwood trees and pupate in the soil. The moths emerge the following year. Like all wild silk moths, the adult moths do not eat. The adult moths live only long enough to mate and lay eggs to start the next generation. Imperial moths are attracted to lights at night, where they will remain throughout the next day. Unfortunately, it is often open areas, like parking lots, that have lights on all night. Remaining in these areas throughout the day leaves the moths vulnerable to traffic and to birds.

Imperial moth outside Howe Hall, Iowa State University campus. Photo by Laurie Hoifeldt.