What's The Buzz? A Penn State Extension Agent On The Brood X Cicadas

May 19, 2021

An adult cicada is seen, in Washington, Thursday, May 6, 2021. Trillions of cicadas are about to emerge from 15 states in the U.S. East.
Credit Carolyn Kaster / AP

As many as 1.5 million cicadas per acre is what parts of southcentral and eastern Pennsylvania and other states could be experiencing soon. WPSU’s Anne Danahy spoke with Tom Ford, a horticulture educator with Penn State Extension in Cambria County, about the Brood X cicadas, and what you should expect to see — and hear.

Here's the interview:

Anne Danahy

Tom Ford, tell us about the Brood X cicadas that we're starting to actually see and hear in parts of Pennsylvania.

Tom Ford

OK, basically, when we look at the cicadas of Brood X, we're looking at something that's been, I guess you would say, a work in progress, since 2004. That was the last time Brood X basically was sort of above the surface and feeding and carried out their various activities. So, it's 2004, eggs are laid. Once the eggs are laid, they sort of bounce to the earth, burrow underground and there, for the next 17 years, stay feeding on the root systems of a variety of shrubs, trees and even grass-type weeds.

Anne Danahy

That's so amazing. Is there anything known about why they all come out together like, “Hey, we've been under here for 17 years. Let’s go!”

Tom Ford

Yeah, there's actually a kind of a reason for it. And actually, some of the data from the 2004, I believe, showed that they emerge from anywhere starting from April to, like, the second week of June. What triggers their widespread emergence is soil temperatures reaching 64 degrees Fahrenheit. There's some that'll kind of test things out … see if the weather's right, see if they can escape predation. But the main brood, the main influx of the population, as soon as 64 degrees hits, they come out in mass, and they overwhelm the predators. And that way, they can keep the species.

Anne Danahy

They can survive. So, they aren't all going to get wiped out. So, we're actually starting to see them. Is that right?

Tom Ford

Yeah, in some areas, probably a little bit further east than our area right now. But, like, in my own yard in the Altoona area, I've seen the little holes, but I have not seen any “adults.” So, any adults that have poked their head out and that have emerged probably have already been eaten, unfortunately. And they actually estimate that they used to be, if we look historically, they will usually be out at the end of May, is when they actually would be seen. But they believe, because of the global warming, that we're seeing them earlier and earlier. So, in most cases, they're seen the first week of May, in some situations. But again, our weather temperature is a little cooler this year, so it's holding them back.

Anne Danahy

And they come out, and they mate. And that's when things get crazy and we hear them?

Tom Ford

Yeah, that's when things get crazy. Because the estimate, again, some of the research that's out there, estimate anywhere from about 1.3 to 1.5 million cicadas per acre. When they first come out, they'll take their exoskeleton, and they sort of crack it over their back. What they try to do is they all come out at once. And … they're the most vulnerable when they first emerge from the soil. So then, what they do is, they come out en masse, they overwhelm the predators. The ones that escape climb to the treetops, and the males then start their symphony. The males are what sings. The males basically have an organ they call the tymbal organ, and it basically makes this sort of resonating sound. They estimate between 100 to 105 decibels per insect.

Anne Danahy

Oh my gosh. So, it can be noisy.

Tom Ford

Yes, noisy.

Anne Danahy

So the males are out there. They’re singing, they're trying to get the ladies.

Trying to get the females. And so, the males sing. They basically sort of strum with their little organ. And then the female, she's rather quiet. This all she really does is she does a simple flick of her wing to tell the male, “You're the one.” And that's what happens. So, and then basically, once they have mated, the female basically lays about 30 eggs a day. But in her lifetime, which usually is about potentially up to three weeks, maybe longer, she can lay up to 600 eggs. So, when you think about the potential if they're very successful, the population should continue to increase over time. And you may start to see some areas that don't have cicada. You may see a little more spread out. But the other thing is, is it's not just one species of cicada in the 17-year brood. There's actually three different species that are in this brood typically.

Anne Danahy

I remember the last one, maybe, that hit this area. I remember driving, like, you literally couldn't drive with your windows down because they could end up, like, bombarding your car. Is that what we should get ready for in some places?

Tom Ford

Yeah, most definitely. They will be everywhere. But … my earliest memory of cicada, I can't remember what year it was, but my grandparents had a small property in Laurel, Maryland, and they had a little pond there. And what we used to do is, they would be out, and we were so curious as kids that we'd pick them off. But our thing was we would go and feed them to the fish in the pond. We take them we throw them into the pond and the bass would strike and, you know, it was kind of fun sport for us as kids to watch them do that. So, when you think about all the birds, all the animals, they're going to have a field day. Fish are going to have a field day. If you're a fisherman, you know, that's a great bait. So, you'll see a lot of benefit from that standpoint. So, a lot of populations, even though it's every 17 years, you know, this is like fine dining time for them.

Anne Danahy

Even if the sound is driving you a little bit bonkers or they seem a little creepy, not the prettiest things, you should maybe resist the urge to try to kill them.

Tom Ford

Most definitely. The damage they do is sort of the feeding damage. When they feed on the root systems of trees and shrubs, it's really sort of incidental. They don't really stress the trees out. They’ll stress the plant material out. The only visible side we'll see really actually damaged from their invasion this year is that when the female oviposits, she will cut a slit into very small branches, usually branches that are pencil-size are a little smaller. And when she cuts that slit into that branch, sometimes these branches will break and crack off, and then what we call flagging. So, once you’ve got flagging of the shoots, then what happened is there's 20 or 30 eggs over there, either they'll develop in the twig and then the larvae, or this case, the larvae, the nymphs, in this case, will drop to the ground and burrow underground. In some cases, the branches will break off out of the ground, and then they'll crawl from the branches then back into the soil as well. But that's the biggest issue of injury. So, if you have a small orchard, fruit crops, something like that, you definitely should be concerned. If you have just planted young trees this year, you should be concerned because they will damage. You will see a lot of damage to young trees. Older trees, the damage is there. But actually, it's nature's way of self-pruning because it basically prunes the chips out and will make the tree bushier. So, the issue is that the younger trees, in some cases can have significant injury. And so, we do advocate rather than using a pesticide in this case, what we’d really rather you do is to get some cheese cloth or mesh that's about one-centimeter square. and use that wrap the tree wrap the specimen you want to protect and gather it around the trunk. That's your best bet until the cicadas are finished their song and dance routine for the season. But, you know, it's much better than using a pesticide. If the pesticides that are either labeled for use or can work, they’re broad spectrum. They kill all the beneficial insects, and they'll make all the other pest problems in your landscape much, much worse.

Anne Danahy

What advice would you have for someone experiencing for the this for the first time who is curious and wants to enjoy them?

Tom Ford

I think for the most part, because it is that you know, a 17-year wait, you know, you're only going to see a certain number of these broods in your lifetime. And we're actually pretty lucky. They said when the first immigrants came to the United States, they had never encountered cicadas before. So, when you're looking at European settlers coming in, the Native Americans knew what they were. They respected them, they use them for food in certain situations. But the first European settlers, it drove them crazy. They thought it was a biblical plague. That's what they were called the locusts. Because they thought it was a plague-like insect because the millions, and they’d just never seen them in Europe. So, it's one of these little peculiarities as far as North America that we see this unique insect.

Anne Danahy

And you can also say, bon appétit, right?

Tom Ford

Bon appétit. They should be high in protein, a little crunchy. I'm sure there's somebody out there that's doing a chocolate rolled 17-year cicada as a dessert.

Anne Danahy

Tom Ford, Penn State Extension horticulture educator, thank you very much.

Tom Ford

Well, thank you, Anne.