Facts, Identification & Control
Cicadas often are incorrectly called locusts. In fact, locust is the common name for the group of insects that are categorized as short-horned grasshoppers. Adult cicadas vary in size depending upon the particular species, but are generally about 2-3 inches long. They have large, clear wings with many easily seen wing veins. Their eyes are large, reddish or black and set apart on each side of the head. The cicada’s immature stage, called the nymph, is wingless.
Behavior, Diet & Habits
The female adult cicada lays eggs on trees and shrubs by inserting the eggs into the small twigs at the outer end of tree branches. Cicadas don’t cause damage by chewing leaves, but do create damage as they lay eggs. Eggs hatch in about 40-60 days and become nymphs. Nymphs drop to the ground, burrow about 1 – 2 feet into the soil where they feed on the fluids in the small roots of the host plant. Mature nymphs emerge from the soil, climb onto surrounding trees or shrubs and mature into adults. Soil temperatures of 64 degrees trigger emergence of the nymphs. Adults live for about 14-50 days during which time they mate, lay eggs and die. Annual and Periodical cicadas are two basic groups of cicadas. Annual cicadas complete their life cycle and emerge from the soil habitat every year, while the Periodical cicadas emerge at either a 13 or 17-year interval. Periodical cicadas are so predictable that charts are created to forecast when and in what states they will appear. Most species of cicadas in the U.S. are annual cicadas. One of the most impressive cicada predators is the cicada killer wasp, a burrowing insect that looks like a huge yellow jacket. During the time of the year that adult cicadas are active, cicada killer wasps are often seen either carrying or burying a cicada that was paralyzed by the wasp’s sting.
Homeowners can control cicadas by removing adults or nymphs off the plants by hand. This may be an overwhelming task, though, especially when dealing with Periodical cicadas. More effective control methods include spraying them with water from a garden hose to knock them off plants or placing foil or sticky bands (barrier tape) around the trunk of trees and larger bushes to prevent the cicadas from moving up the plant to feed and lay eggs. If homeowners need to protect valuable plants, they should wrap the plants with netting purchased at garden and plant nursery centers to exclude cicadas from the plants. Avoid using insecticides since cicadas will come to your plants from locations outside your property in such large numbers that spraying is of little benefit. While cicadas appear daunting due to their large numbers, they do not bite or sting and will not harm people. While eating cicadas usually does not harm pets, owners should not let their pets eat large numbers of cicadas. Cicada “singing” can be heard for up to ½ mile away, making cicadas the loudest of any other insect in the U.S.