The objective of this study was to determine differential detoxification enzyme levels among different abdominal color morphs (orange/yellow, blue/green and gray/brown) of Asian citrus psyllid (ACP). Glutathione S-transferase, cytochrome P450 and esterase activity were measured. First, we used a topical bioassay to determine the insecticide susceptibility to adults of three color morphs. The insecticides chosen were from four different modes of action. Three color morphs of adult ACP were collected in the field from Lake Alfred, FL. Tested insecticides were of analytical grade and included bifenthrin (99.8%), dimethoate (99.8%), flupyradifurone (99.5%) and aldicarb, (99.7%). The LD50 value and 95% fiducial limits for aldicarb (carbamate) were1.52 ng/�l (0.86-2.74) for orange/yellow; 2.06 ng/�l (1.17-3.71) for blue/green and 2.29 ng/�l (0.52-12.37) for gray/brown ACP. The LD50 value and 95% fiducial limits for diamethoate (organophosphate) were 0.32 ng/�l (0.18-0.56) for orange/yellow; 0.50 ng/�l (0.28-0.91) for blue/green and 0.62 ng/�l (0.35-1.12) for gray/brown ACP. For bifenthrin (pyrthroid), the LD50 value and 95% fiducial limits were 0.10 ng/�l (0.06-0.18) for orange/yellow; 0.13 ng/�l (0.07-0.24) for blue/green and 0.13 ng/�l (0.07-0.23) gray/brown ACP. The LD50 value and 95% fiducial limits for flupyradifurone (butenolid) were 3.79 ng/�l (2.03-7.52) for orange/yellow, 4.78 ng/�l (0.92-46.9) for blue/green and 6.16 ng/�l (3.30-12.50) for gray/brown ACP. The susceptibility to aldicarb, dimethoate and flupyradifurone was significantly higher for the orange/yellow morph as compared to blue/green and gray/brown morhphs. Secondly, we quantitatively measured the detoxification enzyme activity levels of orange/yellow, blue/green and gray/brown color morphs to determine difference between the physiological states of these three color morphs. Cytochrome P450 activity was quantified and expressed in terms of general oxidase level. A heme peroxidation method was used to indirectly determine the P450 activity using substrate of 3,3′,5,5′-tetramethylbenzidine (TMBZ). General esterase activity was measured using 4-nitrophenyl acetate (pNPA) as a substrate. Glutathione S-transferase activity were conducted using CDNB (1-chloro-2.4-dinitrobenzene) (CDNB) as the substrate. GST activity was significantly lower in orange/yellow color (299.70 �1.24 �mol/min/mg protein) than gray/brown (350.86 � 1.19 �mol/min/mg protein) and blue/green (412.25 � 1.37�mol/min/mg protein) ACP adults. Likewise, mean cytochrome P450 activity was significantly lower in gray/brown (0.152 � 0.006) and blue/green (0.149 � 0.005) equivalent units (EU) cytochrome P450/mg protein than orange/yellow (0.179 � 0.008) equivalent units (EU) cytochrome P450/mg protein. Mean esterase activity was significantly higher in blue/green (416.72 � 5.12 �mol/min/mg protein) and gray/brown (154.25 � 5.46 �mole/min/mg protein) than orange/yellow (282.56 � 2.93�mol/min/mg protein) ACP. Results indicated the GST and esterase activity may be correlated with insecticide susceptibility levels. The study shows that activity levels of three important detoxifying enzymes in ACP are potentially different depending on the color morph and may influence insecticide efficacy depending on differential abundance in the field. However, further investigations are needed to compare expression levels of associated genes between difference color morphs. Importantly, insecticide resistance does not appear to be shifting populations of ACP toward more resistant color morphs based on our observations thus far. Work continues on the field investigation comparing different insecticide rotational schemes. We completed the latest rotation sprays in October 5, 2016 but were unable to collect sufficient numbers of psyllids to assess for insecticide resistance. Currently, we are rearing insects collected from the different plots to obtain sufficient numbers for testing in the laboratory. These laboratory cultures established from our field experiments will allow us to determine which rotation schedules tested are best to minimize the chance of resistance development in the field. We expect to have more results at the end of next quarter to begin answering this question.