Monitoring and mechanisms of resistance to insecticides in the Asian citrus psyllid populations in south Florida

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama, is currently one of the most devastating pests of citrus in Florida. Introduced to South Florida in 1998, ACP is a vector of a deadly disease known as Citrus Greening (CG). This disease was initially reported in South Florida in 2005, and since 2006 the deadly combination of insect pest and disease has resulted in an approximate loss of $4.5 billion to the Florida citrus industry. Numerous applications of non-selective chemicals against the various feeding stages of ACP have led to the development of insecticide resistance. In this study, we developed a user-friendly adult vial technique to monitor for resistance in ACP populations. Levels of resistance in field populations (FP-IMOK) were compared with those of populations of susceptible ACP (S-LAB). Results indicated different levels of resistance within and between classes of insecticides. Levels of resistance of ACP populations to carbamate insecticides were 2.2-fold for carbaryl, 2.1-fold for carbofuran, and 1.1-fold tolerance for propoxur. Resistance in ACP populations to the pyrethroid cypermethrin was 32.7-fold and 56.1-fold to the pyrazole fenapryoximate. Data also indicated that mechanisms of resistance to these insecticides were both metabolic and target site. Our results provided useful insights in the development of resistance management strategies for the Asian citrus psyllid.