The beetles feed on leaves of cole crops, mainly turnips. They’re also considered a threat to mustard, radish, collard greens, watercress, bok choy and napa cabbage.
Their eggs can endure consistent 32-degree temperatures, creating the possibility for survival in Kansas, Illinois, Missouri, Kentucky and Virginia, according to the study published in the November edition of the Annals of the Entomological Society of America.
An abstract of the research is online.
The beetle is native to southern South America. It was first reported in the U.S. in 1945 and is found in Texas, Louisiana, Mississippi, Alabama, Florida, Georgia and South Carolina.
In conventional production the beetle is susceptible to foliar insecticides.
For organic growers the researchers are investigating biocontrol options that include the spined soldier bug; green lacewing; trap crops; and fungi that attack beetle larvae, entomologist Ron Cave, associate professor at the University of Florida Institute of Food and Agricultural Sciences, said in a news release.
Cave — one of the paper’s five authors — advises cole crop producers to scout fields in early fall so that infestations can be addressed before beetles proliferate.