Monitoring of Diaphorina citri populations from Florida reveals reduced susceptibility to cyantraniliprole and thiamethoxam

The Asian citrus
psyllid, Diaphorina citri, is an
important insect pest that transmits the causal pathogens of huanglongbing
(HLB) in citrus. In Florida, HLB threatens citrus production and insecticide
overuse for the vector has resulted in evolution of resistance among
populations of D. citri to commonly used insecticides. Cyantraniliprole
is effective against nymphal and adult D. citri. However, since
the introduction of cyantraniliprole use in Florida, observations have
suggested that duration of population suppression following foliar sprays
against D. citri has decreased from 60 to 28 d during the period between
2012 and 2020. Here, we sampled populations of D. citri from four locations in FL
and measured their susceptibility to cyantraniliprole as compared with a
laboratory susceptible culture. A bottle bioassay method was used to measure
direct toxicity of insecticides to D. citri. Our results indicate that sufficient field variation
exists in susceptibility to cyantraniliprole among populations of D. citri
to justify careful management of this insecticide for prevention of insecticide
resistance development.