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The Asian citrus psyllid (Diaphorina citri Kuwayama) is known to exhibit abdominal color polymorphisms.In the current study,susceptibility to four insecticides was compared among orange/yellow,blue/green and gray/brown color morphs of field collected D.citri.The LD50 values and 95％ fiducial limits were quantified for each insecticide and color morph combination and ranged between 0.10 ng/μL (0.06-0.10) and 6.16 ng/μL (3.30-12.50).Second,we measured the detoxification enzyme activity levels of orange/yellow,blue/green and gray/brown color morphs for cytochrome P450,glutathione S-transferase,and general esterase.The mean P450 activity (equivalent units) was significantly lower in gray/brown (0.152 ± 0.006) and blue/green morphs (0.149 ± 0.005) than in the orange/yellow morphs (0.179 ± 0.008).GST activity (μmol/min/mg protein) was significantly lower in the orange/yellow morph (299.70 ±1.24) than gray/brown (350.86 ± 1.19) and blue/green (412.25 ± 1.37) morphs.The mean EST activity (μmol/min/mg protein) was significantly higher in blue/green (416.72 ± 5.12) and gray/brown morphs (362.19 ± 4.69) than in the orange/yellow morphs (282.56 ± 2.93).Additionally,we analyzed the relative expression of assortment genes involved in cuticular melanization and basal immunity.The transcripts of Dopa Decarboxylase and Tyrosine Hydroxylase were expressed higher in blue/green and gray/brown than orange/yellow morphs.The transcription results paralleled the susceptibility of D.citri to organophosphate,neonicotinoid and pyrethroid insecticides.GST and EST activity may also be correlated with low levels of insecticide susceptibility.Cuticular melanization could be a factor for the development of resistance to insecticides among different color morphs.