June 20, 2013
Virginia forestry officials are reporting widespread damage to oaks and other trees from this year's arrival of the 17-year cicadas.
Tree damage is the result of cicada females laying eggs in the thin-barked outer branches of trees and shrubs. The females slice into the branch, then deposit up to 20 eggs.
Forest health specialist Chris Asaro said a single female can create about 30 nests, laying as many as 600 eggs.
“When you consider how many millions of female cicadas were laying eggs over the past few weeks, there are literally billions of slices in the trees,” said Asaro. “ All of these cuts along the length of the outer branches can cause enough structural damage to kill the terminal, which turns brown, a phenomenon known as ‘flagging’ or ‘twig dieback’.”
The degree of flagging on any individual tree may vary from a few scattered branches to almost every available twig.
"You are really starting to see a lot of the branch tips on some of the more mature especially oak trees, white oaks, that are turning brown now," says Norm Carlson from Snow's Garden. "You'll see the end of the branch just kind of breaks over and you will see some damage to the stem and that's and indication that the cicadas have done damage to the tree."
The Virginia Department of Forestry says there is no need to worry since most medium to large-sized trees will not suffer any serious long-term damage.