Bemisia tabaci MEAM1, formerly known as the B biotype, became established in the United States in the late 1980s. Bemisa tabaci MED, formerly known as the Q biotype, was first detected in the United States in 2004. Both species have demonstrated the ability to develop high levels of resistance to a broad range of insecticide, however MED has developed much higher levels of resistance than MEAM1 in some instances, leading MED to displace MEAM1. MED has been grouped based on its intraspecies genetic variability into at least three groups (Q1, Q2 and Q3) that demonstrate distinct host preferences. We present the results of studies evaluating the ability of MEAM1 and MED - Q2 to compete on tomato, pepper, and watermelon. In addition, we present the relative susceptibility of a MED - Q2 population to several key insecticides compared to field collected MEAM1 populations and a susceptible lab MEAM1 population.
