## 2 Materials and Methods
### Olfactometer Assays  
Olfactometer assays were performed between 0900 and 1300 h, using a custom made, two-arms, T-olfactometer from Analytical Research Systems (Gainesville, FL, USA), as described in [PERSON] et al. [18]. Experiments were conducted in a climate-controlled laboratory (25 \({}^{\circ}\)C and 40% RH, L14:D10 photoperiod) with overhead fluorescent lighting set to a 16:8 light cycle. To ensure chemical free ambient air supply, both arms of the olfactometer received charcoal-purified and humidified air from a custom made air delivery system (ARS, Gainesville, FL, USA). A constant airflow of 0.1 L\(\cdot\) min\({}^{-1}\) was maintained through both arms of the olfactometer. The olfactometer was positioned vertically under a fluorescent 23 W light source (FLE23 HT3/3/SW, GE Lighting, Cleveland, OH, USA) mounted within a 1.0 \(\times\) 0.6 \(\times\) 0.6 m fiberboard box for uniform light diffusion. Psyllids were acclimated to the environmental conditions of the laboratory for at least 30 min prior to initiation of experiments, and there was an approximate 2-h interval between the time when psyllids were removed from rearing and when they were assayed. Given their sensitivity to starvation [19], _D. citri_ were not purposely starved prior to assays. _D. citri_ of varying ages were sorted by gender prior to the assays and only females were used for the experiment given their greater response to olfactory cues than males [20]. A single _D. citri_ female was inserted in the olfactometer per replicate, and was allowed up to 5 min to select an odor source. A positive response was scored when an adult _D. citri_ traveled past the divider and into one of the two arms presenting an odor. Psyllids were considered non responders when they did not pass the divider after 5 min. Non responders were excluded from further statistical analysis. After each treatment, the glassware was cleaned with Sparkleen 1 detergent (Thermo Fisher Scientific, Waltham, MA, USA) followed by an acetone wash before placing in a drying oven at 60 \({}^{\circ}\)C for a minimum of 1 h.  
The botanical oils were diluted to 1, 5, 15 or 30 mg in 100 \(\mu\)L of ethylene glycol. Ethylene glycol alone was used as the control. One hundred microliters of the oil mixtures were applied to a one-inch cotton wick and wrapped in a Kimwipe laboratory tissue (Kimberly-Clark, Roswell, GA, USA) and placed in the upstream odor chambers apposing 100 \(\mu\)L of ethylene glycol only (Table 1). Citrus odors were obtained by clipping 4 g of crushed Valencia sour orange leaf flush from citrus plants maintained in the laboratory greenhouse and similarly wrapped in laboratory tissue for placement into the treatment chambers (Table 2). Responses of _D. citri_ to clean air vs. ethylene glycol, as well as citrus leaf volatiles with and without ethylene glycol were measured as additional controls to ensure no bias in the olfactometer prior to evaluation of treatments. \begin{table} \begin{tabular}{c c c c c c c c c} \hline
**Control Arm** & **Treatment Arm** & _D. citri Choosing Control Arm (\%)_ & _D. citri Choosing Treatment Arm (\%)_ & _Non Responding D. citri (\%)_ & \(n\) & \(\chi^{2}\) Value & _p-Value_ \\ \hline clean air & Ethylene glycol & 41.7 & 38.3 & 20.0 & 60 & 0.08 & 0.773 \\ Ethylene glycol & Fir Oil, 1 mg & 38.7 & 45.4 & 16.0 & 119 & 0.64 & 0.424 \\ Ethylene glycol & Fir Oil, 5 mg & 56.3 & 31.3 & 12.5 & **80** & **5.71** & **0.071\({}^{\circ}\)** \\ Ethylene glycol & Fir Oil, 15 mg & 60.0 & 16.7 & 23.3 & **60** & **14.70** & **-c.001\({}^{\circ}\)** \\ Ethylene glycol & Citronella, 1 mg & 38.3 & 50.0 & 11.7 & 60 & 0.93 & 0.336 \\ Ethylene glycol & Citronella, 5 mg & 42.2 & 36.7 & 21.1 & 90 & 0.35 & 0.553 \\ Ethylene glycol & Citronella, 15 mg & 45.6 & 36.8 & 17.5 & 57 & 0.53 & 0.466 \\ Ethylene glycol & Litese, 1 mg & 51.7 & 43.3 & 5.0 & 60 & 0.44 & 0.508 \\ Ethylene glycol & Litese, 5 mg & 42.2 & 50.0 & 7.8 & 90 & 0.59 & 0.442 \\ Ethylene glycol & Litese, 15 mg & 40.0 & 28.3 & 31.7 & 60 & 1.20 & 0.274 \\ \hline \end{tabular}