Periodical cicadas emerged in large numbers in northeastern Illinois on June 6. Typically, this insect emerges in the Chicago area around May 27. The unseasonably cool weather this year, particularly in northern Illinois, may be the cause of the later emergence. Another unusual feature is that the males have not been singing much. Typically, the males do not sing for a couple of days after they emerge, but the longer period this year also may be due to the cold weather. As a general rule, insects are not active at temperatures much below 50 degrees F and are sluggish when temperatures in the 60s. With the warmer temperatures predicted during the week of June 15, there probably will be plenty of singing.
Egg-laying is unlikely to start until a week or so after the males start singing, so there is still time to protect young tree trunks under 2 to 3 inches in diameter with screening or other protective materials.
I appreciate the heavy response to my request for locations of this year’s emergence. I have had reports of cicadas in the Beverly area of Chicago, Chicago Heights, Downers Grove, Elmhurst, Elmwood Park, Flossmoor, Glen Ellyn, Hinsdale, Homewood, LaGrange, LaGrange Park, Lake Forest, Libertyville, Lisle, Lombard, Marseilles, North Riverside, Olympia Fields, Palos Heights, Palos Hills, Western Springs, and Westmont. If you see periodical cicada in areas other than those listed, please let me know—pnixon@ uiuc.edu or (217)333-6650.