Map showing the three cicada broods that are relevant for 2024 emergence. Source: University of Illinois Extension. (Graphic by Illinois Farm Bureau)
April 7, 2024/No Comments
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By Rhiannon Branch
FarmWeek
Illinois will experience a rare phenomenon of nature this year as two broods of periodical cicadas are scheduled to emerge at the same time. This once-in-a-lifetime occurrence won’t happen again until 2245.
Kacie Athey, a specialty crop entomologist at the University of Illinois, said the Northern Illinois Brood that emerges every 17 years and the Great Southern Brood, which emerges every 13 years, will come out simultaneously for the first time since 1803. Stragglers from the Mississippi Valley Brood might also appear in 2024.
While the two broods will emerge at the same time, there likely will be only a few places in central Illinois, around Springfield, where they will emerge in the same area, according to the University of Illinois Extension.
Illinois residents should expect to see and hear them from late May to mid-June.
“They start coming out of the ground when the soil temperatures hits 64 degrees Fahrenheit at the depth that they’re actually at, which is seven-to-eight inches deep,” Athey told FarmWeek.
But what impact will these insects have on agriculture?
Illinois State Veterinarian Mark Ernst said they don’t pose a notable threat to livestock, and University of Illinois Field Crop Entomologist Nick Seiter confirmed cicadas won’t harm row crops. But Athey said tree fruit producers should keep an eye out for them.
“Cicadas do damage by cutting into small branches and laying eggs inside of them,” she said. “So if you are a tree fruit producer here in Illinois and you have young trees, you do need to protect them if cicadas come out in your orchard.”
Athey said the most harm will be to young trees, but mature trees that are planted in high densities are also at a high risk for cicada damage.
“Those trees really resemble young trees more than a traditional mature tree,” she said. “And so those orchards need to be protected.”
Emergence patterns are scattered across the state, but Athey said the periodical cicadas won’t be seen everywhere, so preventative measures shouldn’t be implemented until cicadas are confirmed in the area.
She said males will emerge first and emit a loud singing noise. Therefore, if producers hear it they know to act before the females emerge to lay eggs.
For large-scale producers, she said there are several insecticides labeled for cicada control, but small-scale fruit tree growers and homeowners with young trees should start by wrapping the trees.
“You can wrap your tree in mesh that is one-fourth of an inch or smaller, and as long as you tie it around the trunk, you’ll be fine.” She said to choose a mesh that will allow the tree to get plenty of sunlight and leave it on through June or until you no longer hear the cicadas.
Later in the year, producers may hear annual cicadas, but Athey said those are not a problem. “They don’t come out in the numbers the periodical cicadas come out in and, so even though our annual cicadas lay eggs in exactly the same way periodicals do, there’s just not enough of them to make a difference.”
While they will be loud, Athey encourages people to embrace the rarity. “Periodical cicadas don’t exist anywhere else on the planet except this part of North America,” she said. “This behavior is strange, and it’s kind of cool. So if you can, sort of appreciate the weirdness that are these creatures.”
This story was distributed through a cooperative project between Illinois Farm Bureau and the Illinois Press Association. For more food and farming news, visit FarmWeekNow.com.
More About Cicadas
Q: What’s the difference between the cicadas we see in Illinois every year and these periodical cicadas?
A: Annual or dog-day cicadas appear every summer (July-September) in Illinois. It typically takes two-to-five years to complete their development. Periodical cicadas, on the other hand, take 13-or-17 years to complete their development from egg to adult, and they emerge in mass in the spring.
They also look different. Annual cicadas are about 1½-to-2½ inches long and have a green and brown pattern to green and black pattern, with a mostly white underside. Periodical cicadas are smaller, around ¾-to-1½ inches long. They have black bodies with orange wing veins and red eyes.
Q: What is a cicada brood?
A: A cicada brood is a group of periodical cicadas that emerge in a given year (there can be multiple species). There are 12 broods of cicadas with 17-year life cycles and three broods with 13-year life cycles. Each brood is assigned a Roman numeral. For example, Brood XIII is a group of periodical cicadas that emerge every 17 years – 1973, 1990, 2007, 2024, 2041, etc., and Brood XIX is a group of cicadas that emerge every 13 years – 1985, 1998, 2011, 2024, 2035, etc.
Source: U of I Extension
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