17-Year Cicadas: The Periodical Hatch Explained

Photo by: Renee Grayson (Flickr Creative Commons)

Picture this, it’s late May in the green hills of the Appalachians, you’ve got your trusty 5 WT in hand and as the late afternoon sun hits the trees, you hear it: The screams of thousands and thousands of cicadas. The air feels like it’s vibrating as you wade into the creek and watch as nearly every fish in the water looks up, waiting for those little morsels of free protein to slap down onto the water. This is it, this is the big one – Brood X, the largest of the 17-year Cicada broods in the US both in number and size, and they’re here for a comeback tour almost 20 years in the making.

What are 17-Year Cicadas?

The previous emergence of Brood-X in 2004. Photo by: Brian McConnell (Flickr Creative Commons)

Periodical cicadas are members of the genus Magicicada, which consists of 7 unique species with either 13 or 17 year periods between emergences. This year’s BROOD X falls into the 17-year group, which means their parents (shown in the above photograph) emerged in the summer of 2004.

Cicadas are known for their sometimes deafening mating calls, which can reach an excess of 100 decibels when they’re gathered en masse. You’ll often hear these bugs miles before you’ll see them.

Once hatched, they’ll hang around for a few weeks (usually around a month) before mating, laying their eggs, and dying. And, while they’re active, they can be some of the most fun you can have with a fly rod in your hand.

What are Other Types of Cicadas?

Dead cicada
Photo by Dmitry Barsky (Flickr Creative Commons)

There are around 3,000 different species of cicadas on Earth distributed worldwide. They tend to prefer the tropics and temperate climates. The main difference between species is when they emerge. Annual cicadas can wait anywhere from 1-9 years to emerge, but their emergence is not synchronized like the 17-year variety, which is why you’ll tend to see the annual bugs buzzing in the trees every summer.

The 17-Year Cicada Lifecycle Explained

Periodical cicadas are truly fascinating bugs from an entomological perspective. No other bug has quite the elongated life cycle that these guys do. There is much debate as to why this particular variety stays underground for nearly two decades, but one prominent school of thought is that emerging simultaneously in huge numbers allows the most individuals to survive and mate.

The 17-year cicadas’ lifecycle breaks down into two major parts: nymph and adult.

Nymph Stage

Cicada nymph climbing before hatching from its casing.
Cicada nymph climbing before hatching from its casing. Photo by: Ryosuke Yagi (Flickr Creative Commons)

The nymph phase is the longest part of a cicadas’ lifecycle. For instance, this year’s Brood X has been living and growing underground for the past 17 years, meaning they’re older than most kids in high school right now. While underground they feed on sap slurped up from the roots of vegetation above. The only time you’ll likely see one of these nymphs is when they’re crawling up every tree in sight as they begin their emergence.


Cicada Casing on a fence
Cicada Casing on a fence. Photo by: Yamanaka Tamaki (Flickr Creative Commons)

Once they’re wrapped up their underground prison sentence, 17-year cicadas will crawl out from the dirt and being their ascension of just about any vertical woody surface they can find until they break out of their shell, freeing their wings and take flight.

Adult Stage

Adult periodical cicada
Photo by: Renee Grayson (Flickr Creative Commons)

Having spent the last 17 years underground, once cicadas emerge, they’re hellbent on making sure you, and every other cicada in a 20-mile radius knows it. The mating call of the cicada is almost synonymous with long summer nights, a soft droning somewhere in the woods. But with this year’s brood, the sound will be deafening as billions of these buggers emerge within weeks of each other along the Appalachian Mountains. Once they’ve found a mate, the female will use her sharp mouthparts to carve out a hole in woody vegetation and lay her eggs before dying herself. Depending on the brood and the species of cicada, they can remain in their adult form for up to 6 weeks.

Where Will This Year’s 17-Year Cicadas Emerge?

Brood X Cicada Map
Brood X Cicada Map – AccuWeather

This is the big one. Brood X is the largest emergence of cicadas in number, geographic range, and size. These bugs are here to make an impact. From the southern Appalachians in Northern Georgia, all the way north to southern New York, this year’s hatch will span some of the east’s finest trout waters. Regions that are home to the cicada’s favorite trees: oaks, maples, willows, and ash species, will probably experience denser emergences.

How Do Cicadas Impact the Environment? What do they eat? What eats them?

Periodical Cicada Laying Eggs
Photo by: Carl Mueller (Flickr Creative Commons)

Cicadas have existed on Planet Earth for at least 150–145 million years and have spread all over the world as a result. While there are cicada species out there that can be detrimental to agriculture, the 17-year individuals that will rise from the ground will only likely have light impacts on farming and other forms of vegetation. This happens because these plant species have evolved along with cicadas. For the most part, you’ll just find their casings stuck on trees everywhere, and a few large SPLATS on your windshield.

Cicada diet can vary depending on what stage in their lifecycle they are, but it mostly involves sucking something out of a plant’s root or stem.

Cicada Nymph Diet:

When cicadas are in the longest part of their lifecycle, they feed on the roots of plants where their parents deposited them so many years ago. This has little to no negative effects on the host plant other than a little bit of lost sap.

Adult Cicada Diet

As adults, they use their pointy mouthparts to suck the sap out of young twigs and woody shrubs, doing little to no damage to the plants they’re feeding on.

How to Fly Fish the 17-Year Cicada Hatch

Quite possibly the best and most exciting aspect of the cicada hatch for fly anglers is the fact that there really isn’t a game fish swimming that won’t take a crack at a chunky, struggling cicada on the surface. On a perfect day, you could land anything from trout to 20lb carp on cicada dry flies, meaning it’s really up to you to decide what fish you want to be fighting on the other end of your leader. All you’ll need to do is match your rod & reel setup with the species you intend to target, grab a handful of cicada flies, a leader, and some tippet, and you’re in for an epic (and deafening) day of dry fly action.


Luckily for all fly anglers out there, cicadas are notoriously bad flyers, which results in bugs hitting the surface hard, often putting up decent splashes. What does that mean for you? Well, it just means your casts don’t have to be perfect, and you can often size up tippet depending on the fish your casting to.

Once your fly hits the surface, you can give it some movement simulating one of these red-eyed buggers writhing on the surface, often a trigger for and fish looking up to come have a go at the insect nugget splashing overhead.

If you want to get really technical with your fishing spot selection look for the cicadas’ favorite trees to plant their eggs in. Trees like maples, oaks, willows, and ash are all favorites. If you find those, you’ll likely find these bugs in numbers as they gather to spawn and plant the foundation of the next 17-year brood.

The Best Cicada Fly Patterns

Cicada flies, like all fly patterns, come in countless sizes, forms, and variations, but what remains the same, is that they all feature heavy usage of foam. Since the periodical cicadas have orange and black bodies and wings, that will be your go-to color combo. Below we’ve featured some of our favorite fly patterns and how-to videos so you can get your dry fly box ready for the summer of Brood X. Just remember the Brood X bugs are going to be big, to make sure to tie these on big hooks!

George Daniel’s Must-Have Cicada Flies

The Pine Cone Cicada – Fly Fish Food

You can buy everything you need to tie the Pine Cone Cicada, here, from Fly Fish Food!

Curtis Fry’s Sickada

Project Cicada – Fly Fish Food

Buy them, here!

5 Fun Facts About Brood X

  1. When Brood X was last seen in May and June of 2004, “Yeah” by Usher feat. Lil John, “This Love” by Maroon 5, and “The Reason” by Hoobastank all topped the charts.
  2. Right before the first of brood x emerged in mid-May 2004, the final episode of Friends aired.
  3. Brood X will emerge this summer in 14 states.
  4. Cicadas are a popular delicacy in many countries, served dried or fried.
  5. 17-Year periodical cicadas are one of more than 3,000 species of cicada found on Earth.

If you’re looking for more information about cicadas than you probably need to know, give the website Cicada Mania a look. Although it looks like it was built when Brood X was last flying around in 2004, it has a wealth of fun facts and information about this year’s brood and the history of the bug itself!


  1. I have been lucky enough to fish over Periodical Cicada emergences on two occasions. The first was on Spruce Creek and the Little Juniata in Pennsylvania, during the 2008 emergence of Brood XIV. This was purely accidental; by dumb luck I was in the right place at the right time. The second time was for Brood II in 2013, on a smaller central PA stream that must remain nameless, thanks to a hot tip I received from a kindly, generous individual. All of this background info is by way of making a point. I’ve seen a lot of articles this year about fishing to Brood X of the Periodical Cicadas, with information on the life history of the insects and how to buy or tie flies to imitate them. The information that’s conspicuously absent is that these insects are not everywhere. Their presence can be extremely localized. They can be swarming In one location and completely absent a few miles away. It’s quite difficult to find a spot where Cicadas and fishable water coincide. If someone knows such a spot, of course they aren’t going to broadcast it. Just a reality check…..

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