The beautiful flowers of the ornamental plant geranium attract pollinating insects and predators alike. It tricks the most destructive pest of ornamental and turf plants in eastern United States, the beetle, Popillia japonica. When the petals are chewed by the beetle, they exhibit a twitching stance and become paralyzed for several hours. In the field, the stunned beetle could then be devoured by other predators before it recovers.
This phenomenon was recorded in the 1920s but has not been studied since. Scientists of the U.S. Department of Agriculture Agricultural Research Service in Ohio led by Chris Ranger continued on with the research and started a botanical formulation from geraniums that would be used in managing the beetles. This would be cost-effective since controlling the beetles through insecticide sprays and replacing beetle-damaged plants could cost around $450 million each year.
For details, see: http://www.ars.usda.gov/is/AR/archive/mar10/garden0310.htm