(Undated) -- Have you been hearing the sounds of Cicadas? If not, you will be soon. Periodical Cicadas should be emerging in Northwest Illinois. This is the Iowa brood, known as Marlatt’s Brood III, that covers most of the southern two-thirds of Iowa. It also extends into Illinois and is present in Fulton, Knox, Schuyler, Warren and Henderson counties. It has a disjunct area in northern DeWitt and northwestern Champaign counties. Both sexes of cicadas will be present for 2 to 3 weeks, with the males drying by mid-June. Only the males sing, so that will stop by that time. While the males are singing is a good time to check areas to determine whether small trees need to be protected. Periodical Cicadas expand their range by only about one-half mile at each emergence: and egg-laying is heavier where the Cicadas are more numerous, that is, where the male singing is louder. Insecticide is not recommended. Although pyrethroid and other insecticides kill large numbers of periodical Cicadas, research has shown that they have little effect on the amount of egg-laying and subsequent tree damage.