Don’t Freak Out Over the Cicadas

June 3rd, 2025

   Sometime in the next few weeks, millions of locust-like bugs called cicadas will emerge from 17 years of slumber underground.

This is what a 17-year cicada adult looks like.

   They’ll screech and fly around some 24 counties in central Pennsylvania for about six weeks, no doubt causing plenty of gardeners to fear that their plants are doomed.

   Although the cicada’s Biblical-proportion numbers and grating sounds seem foreboding, this buggish version of Halley’s Comet isn’t harmful to people and doesn’t even pose much of a threat to plants.

   These bugs make up so-called Brood XIV (14) – a band of three different species of cicadas (Magicicada) that emerge once every 17 years.

   They’re forecast to appear around mid to late May in Adams, Cumberland, Franklin, Perry, Schuylkill, Snyder, York, and 17 other Pennsylvania counties as well as parts of 12 other states.

   Periodical cicadas – which are native to eastern North America and found nowhere else in the world – tend to stick to wooded areas and areas with ample trees and shrubs that have been undisturbed for the last 17 years.

   Here’s what’s about to unfold.

   The young, underground-dwelling cicadas burrow close to the soil surface in the spring when they’re ready to emerge.

   When the soil temperature reaches about 64 degrees, the bugs emerge and crawl up tree trunks, weeds, and other upright objects. That’s when they shed their exoskeletons and begin flying and mating.

   Mating time also is when you’ll see a lot of adult cicadas flying around, often bumping into people and objects since they don’t see well and are rather clumsy fliers.

   The males are the ones trying to court female cicadas with a screeching noise that in unison sounds like a train in bad need of oil.

   Adult periodical cicadas are pinky-sized, mostly black in color, and distinguished by their bulging reddish-orange eyes.

   Although they look fearsome due to their size, noise, and bulging eyes, cicadas don’t bite, they don’t sting, and they don’t spread disease.

   In short, they look a lot worse than they really are.

   In early June, impregnated females begin depositing eggs in twigs and branches of various trees and woody shrubs. They do this by using a saw-like appendage (an “ovipositor”) that opens slits big enough to insert about two dozen eggs at a time. Females are capable of producing 600 eggs over their nearly month-long egg-laying period.

   This is the part of the cicada life cycle that can cause some damage to plants. The bugs don’t actually eat leaves or branches, but the cutting damage can cause branch tips to wilt or die from the egg-laying point outward.

Cicadas caused this “flagging” damage to the tips of these oak branches.

   If that happens, gardeners will notice the leaves go limp and eventually brown – a condition known as “flagging.”

   Larger trees easily outgrow this limited damage to their smaller branches. Cicada females generally lay eggs in quarter-inch to half-inch branches.

   However, Penn State Extension says that heavy populations can collectively cause enough damage on young or small trees to result in branch dieback and occasionally tree death.

   If you’ve recently planted young trees and start to see signs of large cicada populations, the best option is to wrap the young canopies in netting (with smaller than half-inch openings) or light-weight fabric row covers (usually used to drape over vegetables in the garden).

   Be sure to fasten the covering to the trunk so cicadas can’t get in from underneath.

   A second strategy – if you haven’t yet planted young new trees and live in a cicada-prone area – is to wait until summer or early fall to do the deed.

   Cicadas lay eggs in about 80 different species of woody plants, including fruit trees, nut trees, oaks, maples, dogwoods, and hawthorns.

   They have no interest in laying eggs in needled evergreens, and they also don’t lay eggs on or otherwise injure flowers or vegetables, although you may see them resting on those plants.

   Even if damage occurs on small trees, most will recover. Just prune off the dead ends, and new buds should eventually emerge from the remaining inner branch wood.

   Penn State Extension advises against spraying. Not only is that less effective than netting, sprays need to be applied every few days and will likely cause off-target injury to butterflies, bees, and other beneficial insects.

   Besides, cicadas have the redeeming quality of being an excellent food source. Birds, rodents, and even cats and dogs find cicadas to be a tasty snack, and their rotting bodies decay into nutrients and organic matter that feeds soil microbes.

   This year’s eggs will hatch in late summer, dropping white, ant-like nymphs to the ground, where they’ll burrow anywhere from two to 24 inches deep. That’s where they’ll spend the next 17 years, harmlessly feeding on fluids from plant roots.

   Some people mistake cicadas for locusts, but although similar in looks, locusts are grasshoppers that typically travel in swarms and cause far more plant damage.

   Periodical cicadas are also confused with annual cicadas, which make the same kind of screeching noise but come up every year in smaller numbers. Annual cicadas also usually emerge from July through September instead of late May through early June.

   This year’s Brood XIV of cicadas is the second largest of the periodical broods.

Read more on cicadas at Penn State Extension