The overall goal of this project is to 1) determine the overall effects of ACPS/open hydroponics growing systems on drought susceptibility and 2) the efficacy of plant growth regulators on mitigating the effects of preharvest fruit drop resulting from HLB. The data are now being analyzed for a formal report/publication. Preharvest fruit drop data from the 4-acre plant growth regulator trial in Lake Alfred are in the final stages of analysis. The anatomical data from citrus trees in the different experimental blocks are also in the final stages of sectioning and analysis. As part of an extension of this project a greenhouse study has been initiated to test the efficacy of 2,4-D and other plant growth regulators on root health in small trees with and without HLB. The plants have been potted, graft inoculated, and their initial root mass measured prior to the first applications of the PGR treatments. These trees will be evaluated regularly over the next six months for changes in growth and physiology in response to the PGRs and HLB.