December 2018�The objectives for this proposal are 1) Conduct ground and aerial applications of fungicides to determine the efficacy and economics of fungicide treatments; 2) Determine if Luna Sensation has enough systemic activity to protect flowers from before they fully develop and open; 3) Determine if the period flowering of trees affected by huanglongbing can be narrowed to eliminate the offseason bloom that contributes to the PFD inoculum increase in groves.�In 2018, two field trials were conducted to evaluate the efficacy of various fungicides as well as some fungicide programs for management of PFD.� In the product screening trial (Trial 1), the top five products all contained ferbam when the number of fruit were evaluated.� In the program trial (Trial 2), only one treatment was recommended so only the first product in a rotation was used.� The results from Trial 2 were more confusing and few consistancies occurred among treatments.� For example, Enable performed the best in one program but there was another program that started with Enable that had signficantly fewer fruit.� In both trials, disease was extremely low and it is difficult to determine if the number of fruit per tree side was solely due to the treatments or other inherent differences among trees. An aerial trial was conducted in 2018 as well as and found that there were more fruit per tree in the ground application than the aerial application but this may be because the trees had a slightly larger canopy in ground application block.� There were no fungicide treatment differences observed.�An attempt to conduct a more controlled Luna Sensation trial in the greenhouse failed because insufficient bloom was induced to undertake the experiment.� This was despite an attempt to induce flowers with cold and drought for 2 months.�The second year of bloom synchronization was undertaken in 2018.� Off-season bloom was suppressed with gibberellic acid (GA) in Navel and Valencia trees.� In both cultivars, the major blooms were compressed by GA compared to the untreated control and fewer flowers were observed.� Trees treated with napthaleneacetic acid (NAA; synthetic auxin) did not have a similar effect.� Despite the significant reduction in bloom with GA, there was no signficant reduction of yield compared to the untreated control.� Applications for the upcoming flowering period have been commenced and it is anticipated that fruit number data will be collected by July.�Minor changes were done to the Citrus Advisory System (CAS) in 2018 to correct some minor problems.� Additionally, the fungicde recommendations, in part from this project, were linked to CAS.� Improvement have been made to the leaf wetness duration estimates for stations that do not have leaf wetness probes or the probes have been shown to be malfunctioning.� Field validation of the CAS has continued in 2018 at 2 sites, Polk City and Fort Meade.� In both sites, we compared an untreated control to the PFD-FAD, a new model CAS, and weekly fungicide applications.� There were no significant differences among the treatments for the number of fruit per tree despite there being 3 weekly applications and 2 or 1 (respectively) for the PFD-FAD system.� No applications were triggered by the CAS.� Since there was no significant differences among the treatments, it means that no applications was the best forecast and significant cost savings could be had by using the CAS.�