Do you hear what we hear….?

That’s magicicada cassini, better known as the cicada. Every year, a fairly small number of these insects emerge from the ground in the eastern United States. But once every 17 years, a truly massive brood of cicadas arrives in the mid-Atlantic and Midwest. The brood tunnels en masse to the surface, lays eggs, and then fills the air with a deafening mating hum that can reach up to 100 decibels before they die off.

They were last here in 2004. Brood X, or the Great Eastern Brood is set to return in May 2021. For the five to six weeks that they’re above ground the live cicadas — and their crunchy, discarded exoskeletons — will be impossible to miss.

The good news is that cicadas won’t bite you unless they mistake you for a plant. They won’t decimate crops like locusts do, and they don’t spread disease. They’re not poisonous, either so there’s no worry if your dog or cat eats one. Just be careful they don’t gorge themselves, as cicadas’ hard exoskeletons and wings can cause pets to choke.

Cicadas are, however, a danger to young trees, especially fruit trees. University of Maryland entomologist Mike Raupp does not recommend planting next spring, “because these trees are going to simply get hammered next year when those cicadas show up.” Trees planted in 2020 will be in danger, as well.

If you’ve recently planted a tree, it’s not too late to save it from the coming swarm. Skip the pesticides, Raupp says, and cover your young trees with netting by the middle or end of April. This will keep the cicadas from laying their eggs in the branches. You should use “fine netting with net sizes about maybe a centimeter or less, and cover those trees entirely. This will protect those trees.”

After mating and laying eggs in the branches of trees, this brood will die off. The cicadas that hatch in 2021 will drop to the ground and burrow into the earth for 17 years. There, they’ll feed on the fluids in tree roots until they emerge to breed in May 2038.