Periodical Cicadas Coming Soon—in Some Places

If you missed out experiencing the huge emergence of 13-year cicadas in 2011 because they weren’t present in your part of Missouri, you may have an opportunity this year. Two other broods of periodical cicadas will emerge this spring, and mostly in places not included in the 2011 emergence. A brood of 17-year cicadas (Brood IV) that inhabits an area extending from Iowa to Texas will emerge in northwestern and western Missouri. A separate brood of 13-year cicadas (Brood XXIII) that extends from Illinois to Louisiana will emerge in southeastern Missouri. The areas where the two broods exist do not overlap, as shown by the Brood IV map and the Brood XXIII map.

Periodical cicadas are expected to emerge from the soil in mid-May, but the timing could change depending on how quickly spring weather warms up. Prior to emerging, cicada nymphs open up half-inch diameter holes in the soil. Some of the holes are topped with chimney-like mud towers. A few days after emerging males begin their noisy “singing” to attract mates. Adults are present through June. For more details, refer to mdc.mo.gov/node/12097 and www.magicicada.org.   

The most visible impact on trees from a periodical cicada emergence occurs when females cut slits into 1/4 to 1/2–inch diameter twigs where they deposit their eggs. Leaves on damaged twigs turn brown (“flagging”), and some twigs may die. The effect on mature trees is minor. Small trees can be protected by placing netting with mesh smaller than 1/4 inch over branches and tying it closed on the trunk. No insecticide use is recommended