There have been numerous reports in the news media about periodical cicadas emerging this year. Brood X, the Great Eastern Brood, is a major 17-year cicada brood that is expected to emerge this spring. It occurs over much of the eastern United States, but in Illinois gets into only Iroquois, Vermilion, and Edgar counties in the east-central portion of the state. Most of the area of these counties will be affected, as well as a narrow band just north of I-74 extending about halfway across Champaign County from the east.
Expect a large number of news reports on this insect because the Great Eastern Brood occurs in Washington, D.C., and in New Jersey, close to New York City. With the high concentration of news reporters in these two cities, many stories are likely to be produced. If the news reports are like they were in 1987, they will make it sound like cicadas are coming out all over the United States, and there will be numerous calls to Illinois arborists and landscapers.
The next major cicada emergence in Illinois will be Brood XIII, the Northern Illinois Brood, which will cover much of the northern half of Illinois in 2007. Brood XIX, the Great Southern Brood, emerges in 2011. The Great Southern Brood northern limit includes Iroquois County on the east and Hancock on the west. In between, the line drops down to include Sangamon. North of that line, the Northern Illinois Brood emerges, with the exception of Henderson, Warren, Knox, Fulton, and Schuyler, northern DeWitt, and northwestern Champaign counties, which will experience an emergence of Brood III, the Iowan Brood in 2014. The Great Southern Brood covers all of southern Illinois except for Crawford, Lawrence, Wabash, Pulaski, Alexander, Union, and Jackson counties, which will experience Brood XXIII, the Lower Mississippi River Valley Brood in 2015.
Periodical cicadas have a major impact on small, newly planted trees. They lay eggs into the trunk, causing it to weaken and snap off. We recommend avoiding major tree planting during the year before a major emergence. If practical, delay planting trees this spring in Iroquois, Vermilion, and Edgar counties in areas where there are established trees that had the cicadas in 1987. New housing developments on agricultural land or other treeless areas are unlikely to have serious cicada problems. Similarly, if all shrubs and trees were removed before houses were built, any cicada nymphs in the soil would have starved to death when the trees and shrubs were removed, so those areas will also not have cicada problems.