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Grab your earplugs, it's about to get noisy. Two broods of periodical cicadas -- the 17-year Brood XIII and the 13-year Brood XIX -- are due to arrive across large portions of the Southeast and Midwest as soon as soil temperatures reach 64 degrees. Talk about the thundering herd -- the sound male cicadas make looking for a mate can reach 100 decibels.

The good news is cicadas aren't interested in dining on farm fields. Periodical cicadas belong to the order, Hemiptera, which includes some irritating agricultural pests such as stink bugs and aphids. But cicadas don't chew crops, according to Gene Kritsky, professor emeritus of biology and the former dean of the School of Behavioral and Natural Sciences at Mount St. Joseph University in Cincinnati, Ohio.

Female cicadas do lay their eggs in the ends of tree branches, which occasionally causes the leaves at the end of the branch to die in a process called "flagging."

"There is a slight risk of damage to very young trees," Kritsky said. So, he recommends waiting to plant trees of five feet or under until the cicada event has subsided around mid-July. Small trees can also be netted.

"For the most part, there's little other risk with this insect," he added. "In fact, in 1869, a number of farmers reported greater yields in their orchards the year following flagging. The egg laying turned out to provide a natural pruning that resulted in greater fruit production," Kritsky said.

Soil aeration, fertilizer (from decaying cicada carcasses), food for birds and tree pruning are generally given as the positives for these winged wonders. However, in popular vernacular, cicadas are cool. They are natural curiosities, much like an eclipse or other things that come around as a gee-whiz only so often in life.

HISTORIC EVENT

The 2024 event is historical because the 17-year Brood XIII and the 13-year Brood XIX only occur together every 221 years. So, the last time these two broods emerged in the same year was in 1803. For reference, Thomas Jefferson was President of the United States and in that year announced The Louisiana Purchase.

Distribution maps show a few small areas where both broods could overlap in central Illinois. That's interesting to me because it is where I live. Whether we will indeed experience a cicada apocalypse is yet to be seen. The area where the two broods could meet is at the edge of their respective distributions and there are questions as to whether both broods will emerge at the same time.

Yes, there are annual cicadas that emerge every year. The easiest way to identify periodical cicadas is to look for the big red bug eyes.

Kritsky encourages farmers to lend a hand in a citizen-science effort to map the emergence. Pitching in to help is as easy as downloading a free app called Cicada Safari from Apple or Google Play. Simply photograph the cicada with your phone and submit to cicadasafari.org, a site also filled with fascinating facts and fun projects for adults and children. Submitted photos are verified by parataxonomists and uploaded to the map, allowing users to follow the emergence as it happens. Video clips (10-seconds) of chorusing cicadas can also be submitted. The calling cicada species can be identified by their calls.

Here are five fun facts from Cicada Safari:

-- Only the male cicadas sing. They have sound-producing structures called tymbals on either side of the abdomen.

-- Cicada gender is easy to determine. The female's abdomen will have a groove in which is found the ovipositor. The male's abdomen will terminate with a square-shaped flap.

-- Adult cicadas do not eat solid food but do drink fluids to avoid dehydration.

-- Adult cicadas do not sting or bite humans, and they do not carry diseases. But they can harm young trees when female cicadas lay their eggs in the tree's new growth. It is not recommended that you spray pesticides to kill the cicadas, because they fly into a tree to lay their eggs and spraying will not kill these incoming cicadas. If you have a young tree, you can loosely wrap the branches with cheesecloth to keep the female from laying her eggs.

-- Periodical cicadas are often incorrectly called locusts. Locusts are grasshoppers and cicadas are more closely related to aphids than grasshoppers.

For more information on cicadas read Gene Kritsky's book: A Tale of Two Broods: The 2024 Emergence of Periodical Cicada Broods XIII and XIX.

Pamela Smith can be reached at pamela.smith@dtn.com

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