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Archive for Thursday, August 31, 2006

Cicada wasps pose little threat to people

August 31, 2006

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Editor's note: Bruce Chladny will be on sabbatical doing research and program development for the K-State Research and Extension offices until January 2007. His research will significantly add to the horticulture support and education for Douglas County.

Hot and dry summer days in Kansas brings out the sound of the cicada.

The cicada is not harmful but has much to fear from the passive female cicada killer wasp.

With food aplenty, out come the predators. These cicada-killer wasps can grow to as much as 1 5/8 inches long, the largest wasp in North America. Large and scary to see, they usually ignore people. If startled or stepped on, the female can sting, while the male cannot. Even then the sting is less painful than that of smaller wasps like the yellow jacket or paper wasp. Recognized by their size, they have a black body with yellow across the thorax and abdomen, with reddish orange wings. They fly 6 to 10 inches off the ground.

A wooded area with soft sandy soil is a typical habitat. This wasp is solitary, with each female taking care of its own. It is not uncommon to find groups of these insects, three to five pairs in one area. The female nests in burrows in the ground. These burrows are quarter-size in diameter and can go 6 inches down and 6 inches horizontally. The male lives on low branches or other foliage. Adults normally live 60 to 75 days from mid-July to mid-September. The adults feed on flower nectar and sap exudates.

Seeming to do all the child rearing, the adult female also hunts. She stings her prey on lower tree branches and then carries or flies the prey back to her burrow. Here it becomes food for the wasp larva. She will lay one egg per cicada and then stuff them into her burrow. Each burrow normally has 3 to 4 cells with 1 to 2 cicadas each. However, it is possible for one burrow to have 10 to 20 cells. Eggs hatch in 2 to 3 days and begin to feed on the paralyzed cicadas. Feeding continues for 4 to 10 days until only the outer shell of the cicada remains. The larva over winters inside a silken case it has spun.

Pupation occurs in the spring. There is one generation per year. Control is usually not required as they are generally harmless and naturally helpful. Young children or those who just don't like bugs may see this differently. Treat the burrows after dark to ensure the female wasps are in their nests. Use Carbaryl (Sevin) or diazinon according to the manufacturer recommendations. Males can be captured with an insect net or knocked out of the air with a tennis racket during the day.

Stan Ring is the horticulture program assistant at K-State Research and Extension-Douglas County. He can be reached at 843-7058 or

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