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Cicadas are expected to appear in Middle Tennessee in May

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The latest crop of cicadas is expected to appear in May after completing their 13-year cycle. Courtesy of UT EXTENSION

A 13-year brood of periodical cicadas, known for their loud song, is expected to appear in Middle Tennessee and many southeastern counties in May.

Called “Brood XIX,” these cicadas lived underground for 13 years during their development. They emerge as adults when the soil temperature reaches 64 degrees at a depth of 8 inches, which is expected to occur in early May.

“Be prepared to experience the periodic emergence of cicadas this spring. Do not worry; You will hear them well. If you are a beetle enthusiast, go out and enjoy. If not, don't worry. It will be over in a month and a half,” said Midhula Gireesh, assistant professor and UT Extension specialist in entomology and plant pathology at the UT Institute of Agriculture.

The periodical cicadas hatching this spring were laid as eggs in 2011, which was considered a spectacular year for the species. Brood was created in 2011

Periodical cicadas, known in the world of entomology as Magicicada, have the longest development period among all insects. Depending on the breed or species, they spend 13 or 17 years underground in larval form, feeding on plant roots. The 13-year periodical cicadas are more common in the southeastern United States, whereas the 17-year cicadas are mostly found in the northern states. Different populations or broods emerge over the years. The 17-year-old Brood This is the first time since 1803 that Brood XIX and Brood XIII are created in the same year. However, we will not experience both broods in Tennessee.

Adults are about 1 to 1.5 inches long and mostly black with reddish-orange eyes, legs, and wing veins. They are harmless to people and pets because they do not sting or bite. They also do not feed on foliage after they emerge. However, egg laying can damage young trees, shrubs and ornamental plants. Gireesh recommends protecting young and valuable plants with no more than a quarter-inch mesh or cheesecloth while leafhoppers are present. Insecticide sprays are not effective.

The big question: Why are they so loud?

“As soon as they emerge, males begin 'singing' to attract females using two drum-like membranes on the side of the abdomen, called pelvises,” Gireesh said.

After mating, the females begin laying eggs by making slits in tree branches with their knife-like ovipositor. The female lays around 24 to 28 eggs in each crevice. A single female can lay between 400 and 600 eggs. After six to seven weeks, the eggs hatch and the nymphs, which are white and ant-like in appearance, drop to the ground and bury themselves in the soil to find suitable roots. Nymphs grow slowly and feed by sucking sap from roots, but they appear to have no noticeable impact on the trees. After 13 or 17 years, the nymphs emerge and find places to molt, and the new adults emerge a few hours later and fly.

Adult periodical cicadas live above ground for only three to four weeks. The young of brood XIX will hatch in 2037.

Common annual cicadas can be seen every year and are generally larger than periodical cicadas. Annual cicadas are about 1.5 to 2.5 inches long and have a green-brown or green-black pattern with a predominantly white or grayish underside. Annual cicadas are active during the hot summer days from July to September. These cicadas have a life cycle of two to five years and emerge in relatively small numbers each year to be seen and heard.

For more information, please contact Vickie Witcher with UT Extension-Dickson County at (615) 446-2788 or [email protected].