The Upper Cumberland preparing for a new round of cicadas within the next six weeks.
This year’s expected cicada brood emerges every 17 years. The cicada sounds distinct, but the damage caused? Tennessee Tech Horticulture Professor Douglas Airhart said trees will be most impacted.
“The females lay their eggs on stems that are about pencil thick,” Airhart said. “They’ll poke a hole and lay three, four, or five eggs. Then they’ll move up, poke another hole. It scars the epidermis and flow tissue of the tree, which creates nodules on those branches.”
The website, Cicada Mania, said Putnam and Cumberland Counties are expected to see the highest populations. Airhart said the best way to protect trees is with a net that completely covers the tree.
“It has to be about a centimeter, which is around a quarter or a third an inch square, although they still might be able to sneak through,” Airhart said. “A one inch bird netting won’t hold them in or keep them out, they’ll walk right through.”
Airhart said the net must cover the entire tree to be effective, making it much easier to defend smaller trees. Airhart said the eggs disrupt water flow in the trees, which can cause them to wilt and die.
Airhart says there could be enough cicadas that they resemble a cloud when they move, but it is difficult to forecast an exact number of cicadas. He also says natural predators could slow the initial impact, but they get tired of eating cicadas after awhile.
Airhart says the high volume of cicadas makes them difficult to control, but his team has researched mitigation strategies.
“In Cookeville, we actually collected trees at the sports field and Cane Creek Elementary School. We would just go out to those trees and collect thousands of cicadas,” Airhart said. “We took them back to the research station at Schipper Farm and treated them with thousands of chemicals to see which ones work and which ones don’t. But [cicadas] fly away, so it’s intermittently effective.”
This year’s brood of cicadas was last seen in 2008. Last year, part of the Upper Cumberland saw a different locust brood, the 13-year periodical cicadas, which will not return until 2037.
The forecast projects that most of the eastern U.S. will see a cicada outbreak throughout May and June. Cicadas typically emerge when the soil temperatures reach 65 degrees, or when air temperatures climb into the 70’s and 80’s.
