Two Las repressors from Objective 1, and a Wolbachia repressor from Objective 2 were all confirmed as functional transcriptional regulators of Las phage genes and with DNA binding sites within key Las phage promoter regions. These three repressors are therefore potential chemical targets for inhibitors that may control HLB. In addition, a likely Las virulence effector, a secreted peroxiredoxin enzyme, was identified in Objective 3. This enzyme appears to prevent citrus host phloem cells from killing Las and also blocks systemic host responses to Las. This secreted enzyme is also a high value potential chemical target. A high throughput fluorimetric thermal denaturation screen was first used to identify chemicals that bound to the Las peroxiredoxin target. A total of 320 phytochemicals were screened, resulting in the identification of fourteen (14) lead candidates for phytochemical control of HLB. Several of the lead candidates are generally recognized as safe (GRAS) and are not pharmaceutical drugs. The larger library of 1,600 chemicals, including drugs, was then further screened using a direct enzymatic activity inhibition assay to independently verify the results of the fluorimetric assay and also potentially identify additional inhibitors that directly affect the secreted Las peroxiredoxin. Peroxiredoxins react with hydrogen peroxide and both aliphatic and aromatic hydroperoxide substrates. Of 1,600 chemicals screened, 28 exhibited a strong inhibitory effect on the Las peroxiredoxin. Based on possible commercial value as being both GRAS and relatively inexpensive, 7 chemicals were selected for further study. Three of the 7 chemicals were confirmed repeatedly as having a strong inhibitory effect. One of these was confirmed inhibitory by both fluorimetry and direct enzyme inhibition assays. These three chemicals are currently being evaluated for potential direct bactericidal and phtotoxicity effects and for capacity to cure Las infected periwinkle and citrus. Despite repeated attempts, the fluorimetric assay proved unusable for chemical library screening of the three repressor proteins. All three repressors are very small DNA binding proteins with little protential to form folded structures, which is necessary for the thermal denaturation assay. Alternative approaches involving interfering with DNA binding of these represors are currently underway.