For the second year, we compared the densities of Asian citrus psyllid (ACP) on reset trees planted in solid set plantings (all trees planted within the last two years) versus the densities of psyllids on resets (trees planted within the last two years to replace mature trees) present within mature groves. This year, the experiment was conducted in three groves of three different citrus varieties (Hamelin, Grapefruit and Valencia). More psyllids were found in the solid set plantings as compared to the resets within mature groves. These data confirm last year’s results. Overall, this study indicates that solid set re-plantings will require more intense vector management than resets within mature groves. Regarding laboratory experiments, we investigated the effect of abiotic and biotic factors on host acceptance of the ACP. We know that ACP are attracted by HLB-infected citrus, and that this attraction is achieved through the emission of Methyl salicylate (MeSA) by the plant. We now investigated how abiotic factors such as drought stress and time since Clas infection may affect the behavior of ACP and the release of volatiles by citrus plants. We found that HLB-infected plants that were more attractive than non-infected plants during olfactometer assays in control conditions, were not more attractive as compared with non-infected plants if they were submitted to drought stress. Leaf volatile collections and GC-MS analyses revealed that HLB-infected plants under drought stress were characterized by a decrease of MeSA emitted, compared to HLB-infected plants under control conditions. In our experiments, drought stress consisted of decreasing soil moisture from 95% to 35% of the water carrying capacity of the pot. We also found that plants infected with the Clas pathogen for over 18 months (‘old infection’) were no longer attractive in olfactometer assays as compared with control plants; whereas, citrus plants infected for 12 months (‘young infection’) were strongly attractive to ACP as compared to control plants. This was confirmed by settling experiments showing that ACP preferred to settle on infected versus non-infected plants, but also preferred settling on young infected plants rather than on old infected plants. Again, these behavioral results were associated with a reduction in the amount of MeSA emitted by plants infected with the pathogen for more than 18 months. We are currently measuring the gene expression of methyle-transferase in citrus plants depending of the time since infection, to investigate if this reduction in MeSA emission is associated with a reduction of the mRNA abundance of the salicylate methyltranferase gene (CsSAMT) that we have identified in the citrus genome.