By now, you’ve probably heard that periodic cicadas are expected to emerge soon. If you’re thinking “Wait, hasn’t it only been a couple years since the last cicada emergence?” – you are correct. In 2011, we saw Brood XIX, which emerges every 13 years. This year, Brood II – which has a 17 year cycle, will be showing up soon. Seventeen different broods have been identified since the nineteenth century; two have become extinct.
Periodic cicadas are only found in the eastern United States. The cicada nymphs live underground, feeding on fluid from tree roots. In the spring of their 13th or 17th year, the cicadas emerge from the ground when soil temperature is above 64 degrees. They molt and begin their noisy chorus to attract mates. Once they have mated, females lay eggs in eggnests they construct in tips of small living twigs. Once the eggs hatch, nymphs burrow into the ground where they remain until the next emergence. Their large numbers ensure that plenty will be able to breed even when predators have eaten their fill.
Cicadas are not harmful to vegetable crops, people, animals, or mature trees. If you have young fruit trees, young blueberries, or a prized ornamental tree or shrub, you may want to consider protecting them with netting. However, the Triangle is in the southernmost part of Brood II’s range, so we could see fewer cicadas this year than in 2011. Periodic cicada adults are only around for 4-6 weeks, so chemical control is not necessary in most cases.
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Thanks to Christie Parker for some source material for this article