In some parts of the country, Cicadas will be the "Pesky Bugs" of 2004.

Other areas of the United States will be spared this year, only to experience their own Cicada invasion in some future year. When a particular brood matures and emerges, it is usually in many millions of insects. Fortunately, their adult life span above ground is very brief.

Cicada is a flying, plant sucking insect that emerges in period cycles. Nymphs suck juices from roots of plants. Egg laying females cause significant damage to trees during their brief, adult stage. They are not harmful to humans. Counter to some rumors, they do not bite, nor do they often land on a human or animal.

Types

There are two basic types of Cicadas:

Periodic, 2-8 year cycle- These insects "seem" to appear every year in some areas, because their life cycle is staggered. Actually, a different brood is hatching each year to make it seem like they are annual. 

13 to 17 year cycle- This group does not appear every year. When they do emerge, it is huge numbers. They are sometimes called "17 Year  Locusts". Although, they are not related to locusts.

The Life Cycle

Cicada nymphs emerge from the ground in periodic cycles. They climb up trees and quickly shed their skins(molt). An adult, flying cicada emerges. The adult Cicadas' entire purpose in life is to mate and produce offspring. You can hear the males' mating "song" from early morning to nightfall. In heavily infested areas, the noise can be quite disturbing. After mating, the female lands on twigs of deciduous trees, cuts slits in them, and lays her eggs in the slit.

Adults do not eat. Rather, damage to trees is caused by the adult female as she cuts slices in twigs to lay her eggs. Shortly after mating, the adult Cicada dies.

The eggs hatch, producing tiny nymphs that fall to the ground. These nymphs burrow into the soil and feast on underground roots. They remain there for years, slowly growing, until their periodic cycle calls them to emerge again as adults.

How Cicadas Harm Plants:

It's the female that harms trees. Choosing deciduous trees, she cuts slits in small twigs, and lays her eggs. Where infestations are heavy, the egg laying process is repeated on a tremendous number of twigs. This causes the twigs(or ends of the tree) to die, and often break off. With a heavy infestation, it often destroys young trees and bushes. While the damage may look bad on large trees, a mature tree can usually  survive the damage.

Protection:

Insecticides tend to be ineffective.

Many animals and insects will eat Cicadas. They emerge for a very brief period of time in huge numbers. The feast is short lived. Natural predators don't make a big dent in their populations.

Insect Nettings are the most effective way to protect your young trees which are most susceptible. A cheesecloth or insect net will keep them out of the tree. The netting needs to be wrapped completely around the tree and tied, or sealed off to keep any insects from entering. Because Cicada are large insects, a 1/4" netting is effective.

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