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Cicadas Are Finally Gone, But They Left A Little Parting Gift

BALTIMORE (WJZ) -- After a noisy few weeks, the cicadas have finally cleared out but not without leaving us with a parting gift.

Brown spots on the tip of tree branches are known as flagging and are caused by the female cicadas. They use their "ovipositor" to cut tiny slits in the tree branch to lay their eggs. The cuts are deep enough to stop sap and water from reaching the end of the branch making it turn brown.


The good news is: it's mostly harmless. Erik Dihle, an arborist for the City of Baltimore, said it's more of a cosmetic issue.

"If you want to snip it down to where the green growth is, new branches will come out and the tree will be fine," explained Dihle. The caveat being really young trees, which is why you saw some people wrapping them in netting.


"If it's a baby tree with a considerable amount of the top dieback, there's a small chance you would want to replace that tree," said Dihle.

The eggs that are laid in the branch will eventually hatch, fall to the ground, crawl underground.  They will emerge in the year 2038 and start the process all over again.

"This is nature," said Dihle. "How often do we get to see nature here in Baltimore? Where we can see the real progress."

The cicadas tend to only lay their eggs in branches that are the thickness of a pencil. They prefer oaks, maples, and fruit trees. You will rarely find them in evergreens.

This story was first published on July 6, 2021.

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