RALEIGH, N.C. (WNCN) — As we get more consistently warmer days, we are about to see an invasion that happens only once every 17 years.

For almost two decades, they’ve been maturing underground, sucking sap from tree roots.

But before they can make an appearance, they need the ground warm enough for them to emerge.

Millions of cicadas will burst forth once the days are consistently 64 degrees or warmer for several weeks, usually in mid-April to mid-May.

Some people have fears they’ll swarm like locusts, which periodically sweep through places overseas eating everything in sight, but that’s not what happens with cicadas.

(Getty Images)
(Getty Images)

As they emerge, it’s not necessarily what you might we see.

“It’s more like … what you’ll hear,” says Whitney Swink, an entomologist at North Carolina Department of Agriculture.

The noise that a group of these makes has been recorded as loud as 80 to 100 decibels, which is the equivalent of a lawnmower or motorcycle.

“They are most active during the day,” said Swink. “So daytime is when you’ll expect to hear the sound, especially on summer days.”

There are many different species of cicada.

The members of the about-to-emerge cicada Brood 10 are distinguished by their red eyes, black bodies (about an inch long), and bright orange veins in their wings.

“The adults, when they emerge, their main goal is to mate and lay eggs,” said Swink.

Although you’ll see and hear them everywhere, you don’t need to fear them for these reasons:

  • They’re not venomous
  • They don’t bite or sting
  • They won’t invade your home
  • They won’t ruin your garden

“Birds will love this. Reptiles will love this. Even spiders will have a buffet,” said Swink.

However, young saplings or some diseased weakened trees could have problems.

“The females will cut a kind of slit inside the bark of the tree to lay her eggs.” said Swink. “That can cause ‘flagging’ on a tree where the leaves kind of droop.”

However, she said, “If it’s a big healthy tree, it might lose one limb, but otherwise it will be completely healthy.

To protect saplings from egg-laying by the cicada, the USDA recommends you cover them with fine netting while the cicada are active.

Cicada broods are always emerging, but the 17-year ones will be prevalent in the mid-Atlantic states this time around.

The newly-hatched ‘nymphs’ as they are called, will drop from the trees to the ground, where they will be good for the soil, burrowing tunnels which will aerate it.