Thursday, April 7, 2011
When Cicadas Invade Your Yard
Some time in late April or early May when the soil temperature reaches 67 degrees, a red-eyed swarm of swarm of cicadas will creep from underground, climb trees, emerge from their shells and begin flying and singing at the top of their lungs in an effort to attract a mate. This happens every 13 years—and when it does, the air over much of Middle Tennessee is filled with their ear-splitting mating calls.
Often confused with locusts, scientists call them Periodical Cicadas, Brood XIX. These insects are not poisonous. They don't transmit disease. They cannot sting and adult cicadas live for only four to five weeks. The adults do not feed on foliage, but the females can cause damage to young trees.
Tips for Tree and Plant Protection:
The female cicada has a knife-like ovipositor that she uses to slit twigs before she lays eggs inside the slits. Once hatched the young cicadas fall and burrow underground. Each female can lay a total of 400 to 600 eggs and the multiple punctures pose a threat to young trees by causing twig tips to wilt and die. Apple, pear, dogwood, oak and hickory are the favorite hosts, but you can see the puncture marks on many tree species. When feasible, small, valuable shrubs and trees may be covered with a loose woven or spun fabric such as cheesecloth or floating row cover for protection. This covering should be secured at the trunk to prevent infiltration. Delay pruning young trees until after cicada emergence so damaged branches can be removed. If pruning is done before eggs hatch, burn the damaged twigs.
The apocalyptic swarm may be unnerving, but it is nothing to worry about. Most trees and shrubs did just fine back in 1998 during the last outbreak of Brood XIX cicadas. Birds, squirrels, spiders, snakes & family pets find the bugs to be very tasty. The bugs that don’t get eaten create piles of rich compost that nourish plants. It’s one of those circle of life things that you just have to endure once every 13 years!