HLB is known to make citrus roots more susceptible to Phytophthora root rot. It also reduces the efficacy of chemical management of Phytophthora root rot, creating a difficult management scenario. Current Phytophthora management recommendations are based on pre-HLB work done in the 1980s. These three conditions raise the question of whether yield improvement from Phytophthora management is enough to pay for the management costs themselves. The goal of this project is to develop new soil propagule density managment thresholds and recommendations for chemical management of Phytophthora root rot based on ecomonic analysis of yield responses in different soil conditions. Yield has been collected from Hamlin sites and the Valencia harvest is being planned currently. Phytophthora samples have been taken and this years treatments will begin in April. We have built plot by plot microjet irrigation systems that connect to our trailer mounted handgun sprayer to mimic irrigation injection of materials for ease of application. We are currently adding the split plot factor to our plot design to begin foliar brown rot sprays in midsummer through October. We are preparing to inoculate seedlings with HLB for an additional greenhouse experiment to determine if the newly labeled chemistries have the same limitation on HLB-affected plants as fosetyl-Al and mefanoxam have shown. Many of the new chemistries are directly effective against Phytophthora in the soil rather than acting after uptake by the roots, so this is likely to reduce the limitations of Phytophthora management in HLB-affected groves and test the hypothesis. We are waiting for enough CLas+ budwood for graft inoculations or a large enough field population of psyllids after the spring flush to do a psyllid inoculation, whichever comes first.