Cicadas waiting for the last freeze before they emerge


MIAMI VALLEY, Ohio (WDTN) – Billions of Cicadas are preparing to emerge from the ground. Wright State University professor of biological sciences, Don Cipollini said the bugs won’t be flying around in April.

The cicadas are waiting for warmer soil temperatures. Cipollini said this means they will be waiting until after the last freeze.

“I think we’re still a few weeks away from the start of the emergence,” Cipollini said.

These cicadas are known as Brood X. A periodical cicada that spent the last 17 years under ground.

“The basic rule of thumb is that the cicadas will emerge when the soil temperature reaches about 64 degrees,” Cipollini said.

The cicadas recognize 64 degrees as a safe temperature. While they wait for the soil to warm a few degrees Cipollini said they are digging holes.

“So, what people are starting to see now are what are called cicada chimneys,” Cipollini said. “Which are places where they will eventually emerge.”

On Monday the air temperature was 67 degrees in Dayton. About 2-4 inches into the soil the temperature was 58 degrees.

“It does suggest to me that we have several weeks to go before the emergence will start,” Cipollini said. “It takes a long time actually to heat up the soil from 58 degrees to 64 at a large scale.”

The cicadas will begin to emerge once they register the soil temperatures is warm enough.

“Expect them to be crawling up trunks of trees, up walls, up swing sets, when they first emerge and shed their last nymphal skin.”

The bug isn’t quite ready to fly after it sheds it’s skin.

“They have to sit fairly dormant for three to five days as their exoskeleton hardens and their wings harden and they mature enough to do their adult business,” Cipollini said.

Once the cicadas have their wings, the males will create the summer song to attract the female. Then the female will lay eggs within the tree branches.

“Within about six weeks of the start of all of this it will be done,” Cipollini said. “Other than the billions of carcasses of cicadas that will hit the ground that you may have to sweep off your sidewalk and maybe rake out of your lawn.”

There will be a lot of bugs, but Cipollini said this is not an outbreak of a damaging, invasive insect. They are not eating crops like locusts, but they do a little bit of damage to trees when they lay their eggs.

“It does create a little damage to young twigs on young trees or on large trees that can lead to branch dieback,” Cipollini said. “Just the end of the branch will die in places where the females have laid their eggs.”

Cipollini said they do not cause long term damage to the tree.

“It’s sort of a natural pruning is how I’ve put it before,” Cipollini said.

He did suggest covering small trees with a net for about six weeks once they start flying.

“Due to their sheer size they can’t handle that kind of damage as well as a large tree,” Cipollini said. “They won’t necessarily die, but you can protect them.”

Cipollini said it’s ok to plant a new tree if you net the tree.

“The other thing you can do is delay your planting until the fall. Fall is a good time to plant trees anyhow and this might be the year just to wait until fall to put your trees in,” Cipollini said.

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