As you probably have read, Brood II of the 17-year cicada is due to emerge from the ground this year. There seems to be some undue panic associated with this. Here is the story.
Cicadas are insects that spend most of their lives (17 years) underground. Eggs hatch and the nymphs attach to tree roots and suck sap. You won’t ever know they are there unless you happen to dig one up.
Seventeen years after the eggs are laid, the nymphs leave the ground, crawl up onto something like a tree trunk, and the adult emerges from the shell of the nymph, like a butterfly coming out of a cocoon sort of. Like all cicadas, they look sort of like cigar butts with wings.
The thing about Brood II is that it is not as widespread as Brood X, the really big brood, which last appeared here in 2004. At my place in Rockville, I had a lot of cicadas during Brood X, but have hardly any in this brood. The University of MD Extension says that “the parts of Maryland that will have emergence are mainly in southern Maryland, Prince George’s County and the lower portion of Montgomery County.”
This particular species is sort of Goth: black with red eyes. They don’t bite, and the adults do not feed. What they do want to do is mate, and to accomplish this, they take off and fly at tree top level, buzzing away, looking for a spouse. The buzzing is nothing like the normal cicada buzz; it’s more of a high-pitched hum, more of a background noise, like traffic on the Beltway.
They are weak flyers and not the brightest bulb in the insect world, so they may fly into you or you will see them crawling around on your plants. They are a great food source for birds, and dogs love to eat them, as well. At some point the Post will run some shock-value story about people who cook cicadas and have “great recipes.”
Damage is caused by egg-laying. The female splits small tree branches (ones with the diameter of a pencil) to insert her eggs. After mating, the adults eventually die and fall to the ground. The branch wilts, and eventually the branch usually dies and may fall off the tree, although the latter may take several years. At some point, the eggs/crawlers emerge from the branches and enter the soil. On large trees, it’s just a form of natural pruning. On young trees, and especially fruit trees or dogwoods, it can cause enough damage to warrant protection.
Don’t be running around with a can of bug spray because it’s not necessary. When the cicadas begin to emerge from the ground (they are easy to see, although they usually emerge at night), cover your small trees with bird netting to keep the cicadas out. Otherwise, just try to enjoy what is really an amazing display of nature.
by Larry Hurley