After 17 years underground, cicadas will be emerging in Westchester and Putnam in the next two weeks, when soil temperatures reach 60 degrees, says Jen Stengle, natural resources and horticulture educator with Cornell Cooperative Extension of Putnam.
They have already begun to emerge in Rockland, she says. They tend to be very localized. “Some areas won’t see any. In the 1990s, we had a lot of reports of them along the (Hudson) river.”
“They’re not harmful, they can’t bite you – they have no mouth part,” she says. “They’re not locusts. They emerge, crawl up the side of a tree – or perhaps your house – split their skin and emerge as winged adults.”
The males make a lot of noise, trying to attract mates, she says, and they smack into things as they fly.
“They don’t do a lot of damage to anything,” Stengle says. “The only thing they do damage is young trees.”
Before they die and drop to the ground, after three or four weeks, the females like to lay their eggs on the twigs of recently planted trees, just under the bark. You may see dead branches and a loss of foliage.
During the three to four weeks while the adults are active, Stengle recommends that homeowners with young, newly planted trees cover the canopy and wrap the bark with fine netting (1/2 to ¾ inch, not 1 inch), the kind of netting that people with blueberry shrubs use to protect them from birds.
Once you begin to see dead adult cicadas on the ground, it’s OK to remove the netting. By then, the nymphs, which are the size of an ant, have begun to burrow back underground for another 17 years.
“You may see occasional stragglers next year,” Stengle says. “They didn’t get the memo about 17 years.”
For more information, including maps and audio of how the adult males sound, go to magicicada.org and http://project.wnyc.org/cicadas. The sites allow you to play citizen scientist and report sightings.