Susceptibility of Blissus insularis (Heteroptera: Hemiptera: Blissidae) Populations in Florida to Bifenthrin and Permethrin

The southern chinch bug, Blissus insularis Barber, is a serious insect pest of St. Augustinegrass (Stenotaphrum secundatum [Walt.] Kuntze). Control for B. insularis is mainly achieved through insecticides. This pest has developed resistance to several insecticide classes because of near-constant exposure. The goals of this study were to sample select B. insularis populations in Florida to describe their susceptibility to bifenthrin, document new locations of bifenthrin resistance, and evaluate another pyrethroid, permethrin. Lethal concentration ratios (at the LC50) from B. insularis populations collected in 2006 and 2008 showed a 45-4,099-fold resistance to bifenthrin in Citrus, Escambia, Flagler, Hillsborough, Lake, Orange, Osceola, and Volusia counties. One population in Orange County demonstrated a 212-fold resistance to permethrin. There was a positive relationship between the number of insecticide applications made in 2006 and increasing insecticide resistance. This study documents the first case of insecticide resistance in the Florida Panhandle and the first report of B. insularis resistance to permethrin. Observations made during this study and possible causes for the development of insecticide resistance in B. insularis in Florida are discussed.