2008 is the year of the emergence of Brood XIV of the 17 year cicadas. Many people mark time by the emergence of periodical cicadas. I remember Steve and I were walking across the bridge from Newport KY to Cincinnati OH to go to a Red’s game during the last emergence and the sound of the cicadas was practically deafening—from the mating calls to the crackle of the molted hollow body shells underfoot. It is an unforgettable experience---you most likely have your own memories.
The cicada will emerge as nymphs for 3-4 weeks from the underground where they have been feeding on plant roots. The nymphs will climb into nearby vegetation where they shed their skins –leaving on the plant. They will live for 2-4 weeks, if that is they are not eaten by birds, squirrels, cicada killer wasps, spiders, snakes, cats and dogs, I understand that the newly emerged nymphs taste a little like blanched asparagus so you might want to try some.
So anyway, the entire cicada experience will last for a good 6-8 weeks with the beginning of emergence slated to occur about May 21.
Cicadas damage plants—mostly trees and shrubs by their egg laying practices. The females lay their eggs in small twigs and branches—usually ¼-1/2 inch diameter size. She uses and an ovipositor (an egg laying body part) to make a slit in the twig and then deposits as many as several dozen eggs. Each female can make 40-50 slits to lay and lay as many as 400 eggs. You do the math and you’ll see the potential for damage.
The eggs incubate for 6-10 weeks in the twigs, and then they hatch, the nymphs fall to the ground and burrow anywhere from 6-18 inches into the soil to begin the cycle all over again.
It’s usually not until the end of the summer that the twigs begin to dieback. Mature trees are usually not threatened by this damage, but small trees can require extensive repair pruning to overcome the damage.
Keep in mind that cicadas do not bite or sting and though the aftermath of huge populations can be a smelly affair, they are not toxic. New housing developments will not be as susceptible to damage as older neighborhoods because of recent soil disturbance which destroys nymphs. Periodical cicadas cannot fly far so their damage will be limited to the area immediately around the mergence sites.
Here’s another little silver lining—if you have moles in your yard, they are probably doing a really god job right now of eliminating some of those nymphs. (Although there is an argument that the high numbers of nymphs are actually attracting the moles to your yard.)
Here are some thoughts on control:
First of all, there are no recommended soil treatments for the nymphs—this is where those pesky moles are most likely being your friend—they are eating as many nymphs as they come across!
Secondly, trying to control the adults with insecticides usually does more harm then good because those insecticides will destroy more beneficial insects than cicadas.
(I cannot even bring myself to recommend Sevin or pyrethrum or Permethrins.)
If you have prized specimen plants that are small enough, you can cover them to protect them from females. You have the luxury of being able to wait until you see the nymphs emerging, because it take them a week or two to get ready to lay their eggs. As soon as you see (or hear) the cicadas, use a row cover, tobacco cloth or mosquito netting to completely cover the plant, tying the cover securely around the trunk of the tree to prevent the adults from being able to crawl up into the branches.
Look at the bright side, cicadas can be considered Mother Nature’s pruners. Large trees will eventually drop damaged branches –liken it to tip pruning.
By the way, periodical cicadas are about 1 ½ long; they have red/orange eyes and legs and their clear wings have red/orange venation. Annuals cicada on the other hand have green or brown bodies with black markings, clear wings with green veins and emerge in July/August.
In The Garden,
Cindi Sullivan