2008 Annual Report 1a.Objectives (from AD-416) Determine biological and epidemiological charactristics of citrus HLB and its vector interactions and citrus canker in Florida environment, test various combinations of disease and vector control strategies, develop diagnostic methods, examine latency of transmission, determine effects on fruit quality, determine interaction with citrus psyllid and examine biocontrol potential. 1b.Approach (from AD-416) Through epidemiology field trials test various disease/vector control to develop maximal strategies. Analyze infected/noninfected fruit to determine quality issues, explore various biocontrol agents via transmission studies with vector, explore potential to culture HLB, assess interactions of HLB with citrus psyllid and determine latency of symptom expression and bacterial titer detection. 3.Progress Report This project is related to Objectives 2 and 3 of this in-house project: Develop/refine rapid sensitive detection/sampling methods for pathogens; Develop or improve comprehensive integrated disease management strategies. Nine main areas of research were undertaken: Huanglongbing (HLB) Diagnostics and Detection – Projects were undertaken to evaluate detection protocols to determine which are most accurate and sensitive. Comparisons have been made and analysis is being reviewed. Determination of within-tree distribution of Liberibacter – A project was undertaken to identify which areas of a tree should be sampled. Entire trees were uprooted and dissected into pieces 20cm or less and each of these was assayed via polymerase chain reaction (PCR). This is being examined over time to determine if there are seasonal shifts in pathogen content in various parts of the tree. Phenology of Liberibacter in field populations of adult psyllids – This project was initiated to examine seasonality of HLB in adult psyllids and data continue to be collected. HLB Molecular Characterization – Experiments were established and data collected on the microbial ecology of HLB and its vector. HLB Culturing and Collection of Isolates – Artifical diet systems for rearing psyllids have been developed and tested HLB Pathogen Transmission - Citrus phloem composition analysis – a project was initiated and is in progress. The effect of latency period of Liberibacter in adult psyllids relative to detection and transmission – a project was initiated and data collection has been partially accomplished and is under analyses. Root grafting studies have been established. Multiple seed transmission trial are underway. HLB Resistance - A phloem infusion assay is under initial development. Epidemiology/Disease/Vector Control - Epidemiology of HLB in citrus subjected to different management programs – Field plots were established and six assessments of these plots have been made. Data is being analyzed. New biological control agents – A survey was completed of the current status of parasitism of the psyllid by an imported parasitoid. A new parasitoid species was imported from China and is being established. Chemical indicators of immanent flush in citrus – project initiated shortly and data are being collected. Effectiveness of Guava to control HLB. Field trials were established in commercial and USDA farm plantings to investigate the Vietnamese observation that interplanting citrus with guava suppresses the insect vector of HLB and thereby mitigates disease increase and spread. Data will be collected and assessed to determine the effectiveness of guava as a disease deterrent. Trials were established to examine ability of guava to protect citrus nurseries. Canker Epidemiology/Disease Control/Management - Trials were established to examine the longevity of chemical control, bacterial survival under field conditions, and the use of water soluble polymers to delivery CU++. Canker Survival of Xac on Fruit Effects of HLB on citrus fruit quality – a project was initiated, and assessments of quality of juice have been made. Additional tests will be conducted this coming year.