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Cicadas and the Wasps that kill them

Cicada eggs laid 17 years ago are now emerging in northwestern Illinois. University of Illinois Extension entomologist Phil Nixon said this is the Iowa brood that covers portions of western Illinois, northern edge of Missouri and most of the southern two-thirds of Iowa. The Illinois area covered is Henderson, Warren, Knox, Fulton and Schuyler counties, plus northern DeWitt and northwestern Champaign counties.

In Illinois, periodical cicadas emerge every 13 years in the southern half of the state and every 17 years in the northern half. Livingston, McLean and Woodford counties are at the line of separation between northern and southern Illinois.

The nymphs will feed on the roots of trees and shrubs. They climb to perch on the branches in late spring to early summer. Male cicadas use an organ called tymbal on their abdomens to begin their song to attract females.

Females lay eggs In summer. The female cicadas use ovipositors (an egg-laying apparatus) to cut into branches and insert eggs, weakening the stems.

Despite the fact this periodical cicada outbreak will not affect much of Central Illinois, cicada killers will emerge with the annual dog day cicada emergence in our area, and that's after the periodical cicadas have died. Cicada killers are wasps that look like large black hornets with yellow banding on their abdomens. These insects are considered beneficial because they help control cicada populations.

While deemed non-aggressive, cicada killers can be intimidating when seen in flight, and their excavating and burrowing in dry ground for nest construction can be a nuisance.

When you invade his territory, a male may aggressively approach to investigate, but males are unable to sting. The females can sting but rarely do so because they lack the instinct to guard their nest like the honey bee.

Cicada killers will pollinate plants as they search for their prey. Once the female cicada killer has found and paralyzed a cicada, she will carry it back to her underground nest. The female places her prize in a nest cell, lays her eggs on it and seals the cell. The larvae hatch in a few days and feed upon the still living but paralyzed cicada before forming a cocoon to pupate during winter and early spring.

Do not use pesticides on beneficial insects, but rather takes steps to prevent nests in your yard. Plant ground covers and grass to avoid bare spots, put down mulch and use irrigation to deter nesting