13-year Periodical Cicada Brood XIX - 2011 - Emergence underway
Emergences reported Caldwell- May 13, Christian- May 19, Crittenden- May 12, Daviess- May 19, Henderson, Hopkins- May 16, Lyon- May 12, Marshall- May 20, McLean- May 13, Muhlenberg- May 12, Webster May 18.
Cicadas are distinctive sap-feeding insects that belong to the same insect order (Homoptera) as leafhoppers and aphids. Spectacular broods of periodical cicadas, designated by Roman numerals, emerge at predictable intervals (13- or 17-years) across the eastern US. Representatives of both occur in the Commonwealth. The emergence of milions of these insects in an area provides a striking visual image and deafening sound. They are produced by males using specialized structures on the abdomen. Males fly to high, sunlit branches and sing together in choruses that attract females. Songs of the different species are distinctive and include calling and courtship sounds.
Periodical cicadas have black bodies, red eyes, and red-orange wing veins in two pairs of clear wings that are held roof-like over the abdomen. These clumsy fliers often stay in the upper canopy of trees while they are active from late April thru June. Encounters with periodical cicadas can be unnerving to some but these insects cannot sting and do not harm humans, livestock, and pets.
Here are a few projected dates:
- Emergence begins late April or early May
- Widespread emergence by late May. Males begin to call and form groups that chorus as they attract females for mating.
- Egg laying will begin in mid-May
- Last adults will disappear around mid-June
Protecting Landscape Trees and Woody Shrubs from Damage
Periodical cicadas are potential pests of many trees and woody ornamentals, with the exception pines and other species that produce gummy substances when damaged. These insects can cause problems in orchards, vineyards, nurseries, home and commercial landscapes. Physical injury or “flagging” occurs after females slit twigs to insert batches of eggs. Twigs break at these weak spots and are left to dangle, turn brown and die. This “pruning” is not a serious problem for large trees but can adversely affect the developing structure of small trees. A more subtle impact can occur several years later as growing nymphs remove sap from roots.
- New orchard or landscape plantings should be delayed until after periodical cicada activity has ended for the season.
- Young trees can be covered with netting or cheesecloth to protect the tender twigs. This should be done when the first male singing is heard. Secure the covering around the trunk to prevent cicadas from climbing up to the limbs. The netting should be removed at the end of June or when cicada activity stops.
- If practical, cicada nymphs can be prevented from feeding on roots of young trees by pruning out twigs with egg slits. This needs to be done within a three weeks after egg laying has ended. Although a time consuming process, it may be a viable alternative considering the production life and long term value of backyard fruit trees. Feeding by large numbers of nymphs over several years can reduce the vigor of small trees.
- Insecticide applications generally are of limited use in protecting trees from damage, especially where cicadas are very abundant. Repeated treatment will be needed to deal with new arrivals. Orchards under a routine spray schedule should be treated about twice a week during peak cicada activity. Spray requirements will vary according to intensity of the outbreak, which can range from a few cicadas in some areas to massive numbers in other areas.
Some cats and dogs are intrigued by cicadas and may eat enough of them to cause an upset stomach but cicadas are not toxic and cannot sting.
Periodical cicadas will fly to things that produce noise at some frequencies so they may appear to "attack" weedeaters and lawnmowers. Being somewhat ungainly in the air, these insects may crash into people or machinery but it is unintentional.
Keep us up to date by sending your observations, pictures, etc. of Kentucky cicada activity to: Lee.Townsend@uky.edu.
Links
University of Michigan Museum of Zoology Periodical Cicada Page
Periodical cicadas in Kentucky (Entfact 446) This fact sheet list has information on the life cycle of cicadas and the broods of periodical cicadas that occur in Kentucky.
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