BLACKSBURG, Va. – When you open your window to enjoy the spring weather, you’ll hear more than a breeze — the 17-year cicadas are back.

Millions of cicadas from brood IX will emerge after 17 years underground, and as many as 1.5 million cicadas could inhabit each acre. This brood covers southwest Virginia, parts of North Carolina and West Virginia.

“Communities and farms with large numbers of cicadas emerging at once may have a substantial noise issue,” said Eric Day, Virginia Cooperative Extension entomologist in Virginia Tech’s Department of Entomology. “Hopefully, any annoyance at the disturbance is tempered by just how infrequent — and amazing — this event is.”

That noise you hear is the mating call of male cicadas who are trying to attract the females. While many find the noise interesting or just slightly annoying, some tree growers and orchard and vineyard managers see it as a potentially dangerous signal of danger to their young trees, vines and saplings.

“Cicadas can occur in overwhelming numbers and growers in predicted areas of activity should be watchful” said Doug Pfeiffer, a professor and Extension specialist in the Department of Entomology.

Experts at Virginia Tech say the timing of 13- or 17-year cycles is a mystery of the insect world, but they think it could have to do with avoiding predators.

For more information, you can read the Virginia Cooperative Extension’s factsheet here.