One of the signs of summer in Texas, and throughout the eastern U.S., is the cicada killer. Over the past month or two you may have noticed dime-sized holes appearing in your yard or garden. While many insects (beetles and ants, for example) dig holes, few are so conspicuous as the cicada killer wasp, Sphecius speciosus.
Cicada killer wasps are easy to spot due to their large size; they are typically 1-1/2 to two inches in length. The female cicada killer digs homes for her young in home lawns or in any sandy, bare, well-drained soil exposed to full sun.
Although female cicada killers can sting, they usually ignore people and are rarely aggressive. On the other hand, males are often territorial and may act aggressively. Here’s the deal though. Males don’t possess stingers and are completely harmless. Like some “guard dogs”, their bark is worse than their bite.
Why are they pests?
Even though they are a solitary species, females are known to nest in large numbers in sandy areas like embankments if the soil is dry and capable of holding a big enough population. The large number of nests and wasp activity can become a nuisance. Also the adult wasps, especially the males defending their territory, can be scary to both children and adults.
Why are they good?
Although their name suggests otherwise, the adults of this species are peaceful nectar feeders and occasional pollinators. The females capture cicadas, helping keep the neighborhood a little quieter during the summer.
It is the immature, or larval, stage that feeds on the cicadas brought to the burrow by the adult female. After she finds and stings her cicada prey, she turns the victim on its back, straddles it, and drags it or glides with it to the burrow. One burrow may have several underground cells, each one provisioned with a paralyzed cicada (or two or three) and a single egg is laid before the cell is sealed off. This cicada will serve as a food source for the young as it develops. The typical development for a cicada killer is 10-11 months, with the offspring emerging next year.
Should they be controlled?
Generally cicada killers should be considered harmless and don’t need to be controlled. If the nests cannot be tolerated, a small amount of insecticide dust, such as is sold for control of ants or ground-nesting wasps can be applied to each cicada killer burrow. In garden beds, if you are willing to wait out their summertime nesting season, consider covering the site with landscape fabric and mulch . This should prevent emergence next year and discourage adults from using the site again.
For more information
For more information about cicada killers and other wasps, see publication E-239, Paperwasps, Yellowjackets and Solitary Wasps.
This post was drafted by summer intern, Jeremy Farmer.