Cicadas – are the Brood V coming to a tree near you?
by Daniel Frank, WVU Extension Service Entomology Specialist
Have you heard of Brood V? Brood V is a group of periodic cicadas that will be appearing throughout much of West Virginia in 2016. These cicadas will be emerging in mass from the soil where they have spent the last 17 years sucking the nutrients from tree roots. From May through June the adult male cicadas will announce their presence with a loud chorus of sound that they use to attract a potential mate. Once the females have successfully mated, they will cut small slits in the twigs of trees to lay their eggs. When the eggs hatch the immature cicadas (called nymphs) will burrow into the soil where they will remain for another 17 years to start the process anew.
Periodic CicadasPeriodic cicadas are found only in eastern North America and can have either a 13- or 17-year life cycle. Periodic cicadas that are in the same stage of development, and that emerge together in a given region during the same year, are known collectively as a single brood. There are 12 broods of 17-year cicadas and three broods of 13-year cicadas. Each brood is designated by a unique Roman numeral. Periodic cicada broods are so synchronized developmentally that they are nearly absent as adults in the years between mass emergences.
The emergence of periodic cicadas is anticipated in 2016, but you may see annual (or dog-day) cicadas otherwise. Annual cicadas are found throughout the temperate and tropical regions of the world. In West Virginia, annual cicadas typically have a 2- to 5-year life cycle and emerge in the late summer. The life cycles of annual cicadas are often staggered producing individuals that emerge every year. Annual cicadas have green to brown patterned bodies, greenish wing veins, and dark eyes, as opposed to the periodic cicadas that have black bodies, orange wing veins, and red eyes.
Cicadas are not normally considered important pests. They pose no health threat and will not bite or sting people and pets. Although cicadas are plant feeders, the only noticeable damage they cause to plants results from egg-laying by females. The incisions that egg-laying cicadas make in the twigs of trees may cause those twigs to hang down or break off. This damage can be quite noticeable and extensive during years when periodic cicadas emerge in mass within a given area. Although this damage does not affect well-established trees, it may interfere with the growth or even kill very young or newly planted trees.
Life cycleAll cicadas, both periodic and annual, go through a simple metamorphosis that includes an egg, nymph, and adult life stage. They have piercing and sucking mouthparts, which they use to feed on plant fluids. The wingless nymphs will feed underground on the roots of trees for much of the life span of the insect. When the nymphs reach maturity they will dig their way back to the surface, climb onto a tree trunk or some other surface, then undergo a final molt to become winged adults, leaving their shed exoskeleton behind. The adults will typically live for 2 to 6 weeks to mate and produce the next generation.
Control of cicadas is not necessary most years. However, during years when periodic cicada emergence is predicted in an area, homeowners may want to consider postponing the planting of new trees and covering existing young trees with a fine mesh netting during the egg-laying period. In addition, pruning out and destroying damaged twigs within a few weeks after eggs are laid can help prevent new nymphs from entering the soil. Insecticide treatments are not recommended for cicada control except in commercial tree plantings.