What's That Munching on Our Trees?
By Carol Rawle

Everywhere you go on the ranch these days, you can't help but notice what sounds like something chewing and munching on the trees.  I've been hearing the "clicking" and "clacking" and "rasping" noises for a couple of weeks now, and I don't believe it's ever been quite this loud in years past.  Everyone is asking what it is, concerned it might be pine beetles, or something even more hideous, devouring our trees right out from under us.

Putnam's cicada
It isn't pine beetle, but a smallish cicada about an inch long with very remarkable little wings that are responsible for all the racket.  What we are hearing is the male of the species calling to the females by clicking his wings.  And not to worry, they are pretty much harmless to the trees, and they won't bite humans either.

Even your resident ranger was confused as to the difference between cicadas, katydids, and locusts.  Cicadas are of the Homoptera order and are different from locusts, katydids, and grasshoppers, which are related to each other.  Our cicada on the ranch is the Putnam cicada, which is the most common species of cicada in Colorado, being found wherever you have pinons, junipers and scrub oak growing.

The event that we are witnessing right now is the emergence of the adults from the gound where they've been for the past two to five years.  As the adult emerges, it splits its skin down the back as it crawls up the tree, leaving the empty skin behind where you can sometimes see it stuck to the bark.  The new adult hangs out for a few hours until its wings harden, then flys off to find a mate.  The males create a huge ruckus from dawn 'til dusk, trying to attrack the females.  They are feeding on the plant juices and sap of the trees but causing little damage.  The females lay their eggs by splitting open the twigs and stems of the trees and shrubs, sometimes causing some minor die back.  After the eggs hatch, the nymphs drop to the ground and burrow into the roots where they feed off the roots for the next several years until they reach maturity and crawl out of the ground to begin the cycle all over.

There is no real cause for concern that the cicadas will do much damage, though in a banner year such as this, we may notice a little die back of some twigs and branches on the cedars, pines, and scrub oak.  There is no real effective insecticide to spray them with so it's a good thing they won't be causing much damage.  In another month or so, the noise will have disappeared as the new generation disappears undergound for their long, long sleep.  In the meantime, we can enjoy the symphony in the comfort of knowing that at least this one insect isn't doing as much damage as it sounds like.


For more information click on this link to the Colorado State University Extension web site: www.ext.colostate.edu/pubs/insect/05590.html.