If the nymphs do not construct a cone, it is common to see the hole they make a few weeks before emergence. The cones may protrude two or three inches above the ground and may be one or two inches in diameter. Under certain conditions, cicada nymphs construct small cones or "chimneys" of earth above the soil surface several weeks before emerging. When they tunnel to about 1 inch beneath the surface, they stop and await the proper time to continue. Several weeks before emerging from the ground, the nymphs start to burrow upward. The nymphs are fully grown after the seventh or eighth year, but continue to feed and develop until the spring of the 17th year. Severe decline of apple trees sometimes occurs in older orchards where high populations of cicadas exist. As many as 104 cicada nymphs have been found in one square foot of soil under apple trees. In apple orchards they feed 2 to 18 inches below the soil line. When the eggs hatch, the nymphs fall from the plants and enter the soil where they burrow 18 to 24 inches into the ground in wooded or forest areas. Those preferred by females include oak, hickory, apple, peach, and grape. Seventy to 80 species of trees, shrubs, and herbaceous plants are commonly used by cicadas for egg laying. Moving from one twig to another, a total of 400 to 600 eggs are deposited. Sometimes these rows form a continuous slit 2 or 3 inches long. The pockets are placed close together in a straight row. This process continues until 5 to 20 pockets have been made in the twig. She then moves forward, cuts another pocket, and lays more eggs. In the pocket she lays 24 to 28 eggs in two rows. Using the blades of a curved, saw-like, egg- laying apparatus on the end of the abdomen, the female cicada punctures the bark of a twig and makes a pocket in the wood. Some of the veins in the nearly transparent wings are orange (Figure 2). The adult cicada is about 1 5/8 inches long. In most instances, this loss of branch tips amounts to "natural pruning." Description and Lifecycle Thus, leaves turn brown and the branch tip generally breaks off or "flags" at the egg-laying site. This process causes the twigs to die from the egg-laying site to the branch tip (perhaps 1 foot or so, Figure 1). Injury to trees is caused by female cicadas as they use their ovipositor to insert their eggs in twigs. There is no stripping of foliage as with gypsy moth caterpillars. They do not feed to any extent as adults. Fortunately, cicadas are not especially destructive. The insects mate within 1 week and females begin to deposit their eggs about 7 to 10 days after emergence.Īfter 6 or 7 weeks, eggs deposited in twigs by female cicadas hatch and the tiny young (nymphs) drop to the ground, dig into the soil, and remain there for the next 17 years. In areas of heavy emergence, the noise created can be deafening. Usually the "chorus" begins shortly after day-break and continues uninterrupted until evening. Their sudden appearance in late May or early June is dramatic and usually noisy as the males produce a seemingly endless whirring sound. No other insect causes as much curiosity and wonder as periodical cicadas do.
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