The summer nights of Illinois stir the senses with the illuminating performance of the lightning bug and the concerts of the cicada. The annual cicadas have begun to sing their song, and are imperative in the life cycle of the cicada killer wasp.
Periodic cicadas emerge somewhere east of the Rockies each year, but we will not see them in Illinois until 2020, 2021 or 2024, depending on where you live in the state. Right now in our backyards, we are hearing the annual cicadas, also known as dog day cicadas.
Annual cicadas are green and black with silvery wings and they emerge throughout July. Once hatched from eggs laid in the branches of trees, nymphs fall to the ground and burrow into the soil. The nymphs feed on the sap found in tree and shrub roots for two to five years. When they emerge, they build chimneys, climb up the tree, and emerge as a flying adult from their nymphal skin. Find me a child in Illinois who can say they have not been chased around with one of these scary-looking skins!
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The singing of these annual cicadas (or deafening chorus, depending on your tolerance level) calls the adult cicada killers out of hibernation and above ground. Cicada killers are solitary wasps with yellow banding on their abdomens. They resemble large black hornets. On their search for annual cicadas, they will stop and drink nectar and water from gardens. Despite their menacing name, cicada killers are usually non-aggressive.
The male may investigate a person who invades its territory to determine whether it is another male cicada killer, but it is unable to sting. The females can sting, but lack the instinct to guard their nest as the honey bee does, so will only do so when handled or disturbed.
She prefers dry and bare ground in your backyard to build her nest. Once the female cicada killer has found and paralyzed a cicada, she will carry it back to her underground nest. She places her prize in a nest cell, lays her eggs on it, and seals up the cell. The larvae hatch in a few days and begin to feed upon the cicada before they form a cocoon to pupate for the winter and early spring.
For gardeners concerned about the safety of children or pets, U of I Extension suggests planting ground covers and grass to prevent bare spots, adding mulch, and using irrigation to deter nesting. Cicadas and cicada killers do not cause plant damage that would warrant chemical applications but should be encouraged in the ecosystem of your backyard.
Kelly Allsup is the University of Illinois Extension horticulture educator in Livingston, McLean and Woodford counties.