Methods to control periodical cicadas

WEST LAFAYETTE, Ind. — This year during late May and June the 17-year periodical cicada will emerge throughout Indiana.

Elizabeth Young, an assistant entomology professor at Purdue University, said the female cicadas cause damage to young woody trees, especially fruit trees, when they cut slits into twigs and branches to lay their eggs.

Eventually the branch will turn brown and break off, which is known as flagging and can be detrimental to orchard owners and homeowners who have young trees.

Young shared some options that homeowners and orchard owners can do to limit the amount of damage that is caused by the cicadas.

Cultural Control: Young said this process involves individuals delaying planting new trees and other woody plants until 2021. By doing this, it will remove the chances of young, vulnerable trees being attacked. Young also noted that producers can plan accordingly for future emergences and being prepared when they plant new trees.

Mechanical Control: Young said this type of control is best for small orchards, backyards and individuals that grow organic. This can include the process of netting, which is putting a mesh screen, with holes no larger than 3/8 of an inch. Young said this should be done when an individual first hears the shrill mating song from the male insects. The netting needs to cover the entire tree and should be tied to the trunk of the tree right below the lowest branches.

Another thing that can be done through this type of control is pruning, which is done after the eggs are laid. Young said individuals should cut infected branches off the tree and take them off the property because within four to six weeks the eggs that were laid will hatch and the nymphs will burrow into the ground, where they will eat on the roots of the tree for the next several years.

Biological Control: Young said cicadas have many natural enemies, including chipmunks and birds that will feast on the cicadas when they emerge. However, there will be many cicadas that emerge, so relying just on biological control may not be the best option.

Chemical Control: This process, Young said, is more for large orchards and commercial orchard growers. It’s not as effective as netting, but large orchards may not have the option of netting hundreds of trees. Young said the chemicals should not be used on larger trees because they are not as vulnerable and can take the damage. The focus should be on young trees.