Although it may not feel like it after almost 2 inches of snow and unseasonably cold temperatures, cicada season is nearly upon us. The 17-year periodical cicada, also known by the genus name Magicicada, is set to emerge later this spring.
If you lived in Indiana back in 2004, you will recall the incredible sights and sounds of our last periodical cicada emergence. These cicadas emerge on a 17-year cycle, unlike our “annual” cicadas that we see each July and August. They emerge from the ground on the eve of their 17th birthday when soils warm to 64 degrees, which is about the same time that irises will bloom. They will shed their skin, unfold their wings, and cause quite the ruckus for about 6 weeks. (For reference, the soils here at the fairgrounds are holding steady around 50 degrees.)
Periodical cicadas will emerge in large numbers, particularly in wooded areas, and cause some damage to trees and some shrubs. They coordinate their emergence like this to overwhelm predators, ensuring that a large number of eggs will be fertilized and laid in trees. There are several different “broods” of periodical cicadas throughout the eastern half of the United States. Indiana is dominated by Brood X. Southern Indiana is typically hardest hit, but Montgomery County will see the effects, especially in areas along Sugar Creek and near Shades State Park. Male cicadas are responsible for the majority of the noise, which will sound a little bit like a UFO hovering nearby for the duration of their six-week flight. Female cicadas are the primary perpetrators of damage. Females possess an organ called an ovipositor, which is basically a big egg-injecting needle. The ovipositor is used to slice into tree bark and deposit eggs underneath the bark. Expect to see flagging damage, or small twig dieback and browning leaves, on larger trees. Smaller trees and shrubs are more at-risk for widespread damage, but by and large, periodical cicadas will not kill small trees. Cicadas do not bother garden plants or herbaceous perennials and annuals.
If you have a particularly young and/or special tree or shrub at home that you would like to protect from damage, you can use a mesh screening (either insect or bird screening) with holes that are 1/2-inch or smaller to exclude cicadas. Keep the mesh screening on until the cicada flight is over. We strongly recommend against insecticides for cicadas because of the risks to other insects and the overall expense involved.
If you have further questions about the periodical cicada, visit the Purdue Extension – Montgomery County Facebook page and check out my Facebook Live presentation from April 20 on the periodical cicada.
Ashley Adair is the Montgomery County Extension Educator, Ag and Natural Resource. The office is at 400 Parke Ave., Crawfordsville; 765-364-6363. She may be reached by email at holmes9@purdue.edu.
