Key Features
- Dead Twig and Branch Tips
- Slits Cut in Twigs
- Many Loud Shrieking Insects
Symptoms
Female cicadas damage twigs when they puncture or slit them on trees and shrubs to lay their eggs. Susceptible twigs are between 3/16 and 7/16 of an inch in diameter. Infested branches appear as if the eggs have been stitched in by a sewing machine. These branches will turn brown, die, and sometimes break off. Female cicadas have been reported to lay eggs on over 200 deciduous woody tree species and are common on oak, hickory, flowering fruit trees, mountain ash, and grape. The black bodies, red eyes and wings of the periodical cicada distinguish them from from the less damaging annual cicada.
Biology
They appear in the last part of May and during June. The incessant cadence of high-pitched, shrill sounds announces their presence. Very large numbers of wingless insects emerge from the ground and crawl to find a place to shed their skin and become an adult that lives for one month. During this time they mate, and each female lays 400-600 eggs. Cicadas are abundant only in areas where trees harbored the eggs of the previous generation. After mating, adult females lay eggs in twigs. Eggs hatch into wingless immatures that drop from the tree to burrow into the ground where they feed for the next 13 or 17 years.
Management Recommendations
The sheer number of these insects makes them very difficult to manage. Damage is most severe to new plantings. Mature trees are capable of tolerating injury with little or no significant damage. If possible, avoid planting new trees in landscapes before cicadas stop flying during outbreak years. If you must replant, plan to cage trees to prevent injury. Although effective, insecticides are impractical because they must be applied every 3-4 days to avoid injury during the mating and egg-laying period. Tree nurseries may find it economical to use insecticide to protect their growing stock during outbreak years.
Effective Pesticides
Active Ingredients include: Bifenthrin, Cyfluthrin, Lambda- cyhalothrin, Permethrin
