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GAINESVILLE, Fla. — Gulf Coast farmers know that the invasive yellowmargined leaf beetle loves cooler temperatures, devouring leaves on turnips and other cole crops in fall and winter; now, a University of Florida study suggests the beetle’s cold tolerance could help it spread much further north than its current range.

Researchers report in the November 2012 issue of Annals of the Entomological Society of America that the beetle’s eggs can withstand prolonged periods at 32 degrees Fahrenheit. That means the insect might survive in Kansas, Illinois, Missouri, Kentucky and Virginia, says entomologist Ron Cave, an associate professor with UF’s Institute of Food and Agricultural Sciences.

Native to southern South America, the beetle was first reported in the United States in 1945 and is now found in Texas, Louisiana, Mississippi, Alabama, Florida, Georgia and South Carolina. Larvae and adults feed on the leaves of many cole crops, with turnips being the preferred host. The pest also poses a threat to mustard, radish, collard, watercress, bok choy and napa cabbage.

In conventional production, the beetle is susceptible to foliar insecticides but that’s no help to organic farmers, Cave said. So UF/IFAS researchers are investigating several biocontrol options, including the spined soldier bug, green lacewing, trap crops and fungi that attack the beetle’s larvae.

In the meantime, Cave advises all cole crop producers to scout their fields thoroughly in early fall, so that infestations can be addressed before the beetles become too numerous.

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Writer: Tom Nordlie, 352-273-3567, tnordlie@ufl.edu

Source: Ronald D. Cave, 772-468-3922, ext. 145, rdcave@ufl.edu

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University of Florida entomologist Ron Cave, seen in this file photo, is part of a research team investigating the invasive yellowmargined leaf beetle, which preys on cole crops. A study published in Annals of the Entomological Society of America suggests that the cold-loving beetle could potentially spread further north than its current range, primarily in Gulf Coast states. The beetle can be controlled with foliar insecticides but organic producers need new options, so UF’s Institute of Food and Agricultural Sciences is pursuing research on several biocontrol methods. UF/IFAS photo by Tyler L. Jones

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