Percent mortality of T. tabaci larvae after a 24-h exposure to a diagnostic concentration of lambda-cyhalo-thrin at 100 ppm (A) or a 100 ppm concentration of metho-myl (B). Larvae originated from thelytokous and male-producing populations in New York onion fields during 2003 and 2004. Mean ± SEM) percent mortality is represented by the off set solid circles. Each open circle represents one population in which n = 300-500 larvae in the insecticide bioassay.