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Research Project: Integrated Disease Management of Exotic and Emerging Plant Diseases of Horticultural Crops

Location: Horticultural Crops Research

2017 Annual Report

1a. Objectives (from AD-416):
Objective 1: Describe the pathogen biology and disease epidemiology of exotic and emerging plant pathogens affecting horticultural crops. Sub-objective 1A: Comparative genomics of Phytophthora pathogens. Sub-objective 1B: Population genomics and evolution of Phytophthora pathogens. Sub-objective 1C: Characterize the fungal, oomycete and bacterial microbiome associated with horticultural crops. Sub-objective 1D: Disease surveys of small fruits in the Pacific Northwest. Objective 2: Develop improved integrated disease management of pathogens of horticultural crops. Sub-objective 2A: Integrate disease risk forecasters with models for air turbulence to predict pathogen dispersal and spatially explicit disease risk. Sub-objective 2B: Develop methods to monitor presence of fungicide resistance in pathogen inoculum. Sub-objective 2C: Optimize fungicide selection and application timing to manage powdery mildew on grape berries. Sub-objective 2D: Identify inoculum sources of Botrytis cinerea in caneberry fields and evaluate methods to reduce overwintering populations. Sub-objective 2E: Develop and evaluate alternative control measures for management of diseases that reduce fruit yield or quality.

1b. Approach (from AD-416):
The long-term goal of this project is to develop the knowledge and tools needed to respond to plant disease epidemics using approaches that are economically and environmentally sustainable, with emphasis on increasing our ability to respond to exotic, emerging, and re-emerging pathogens. This will be accomplished through trans-disciplinary approaches that increase our knowledge of pathogen genetics, biology, and disease epidemiology and incorporates this information into decision support aids for horticultural crops. The biology of exotic, emerging, and re-emerging plant pathogens is either poorly understood or inadequate to enable economic and environmentally sustainable management. We will develop and test methods for monitoring pathogen dispersion and describe the genomes, evolutionary history, population structure, genetics, epidemiology, and ecology of these pathogens. This knowledge will then be used in Objective 2 to develop decision support tools for producers of horticultural crops. Once there is a more detailed understanding of pathogen ecology, this knowledge will be translated into disease management strategies that are continually optimized and/or improved to address changing climate, market and regulatory pressures. We will develop and improve disease management strategies for select pathogens affecting horticultural crops. The development and improvement of integrated disease management strategies for endemic pathogens will also improve our ability to respond to changing climatic conditions while enhancing the economic and sustainable production of horticultural crops.

3. Progress Report:
This reports progress for project 2072-22000-041-00D, which started in May 2017. It replaces and builds upon project 2072-22000-039-00D "Exotic and Emerging Plant Diseases of Horticultural Crops." Under Sub-objective 1C, experimental plots were established with several commercial raspberry growers in Northern Washington to examine how the fruit microbiome develops in relation to fruit diseases. Both traditional culturing and next generation bioinformatics approaches are being used to characterize the microbial succession. The combination of approaches will also help direct the development of potential biological control agents by identifying the microbes associated with reduced fruit disease and that are culturable. In Sub-objective 1D, we conducted extensive surveys of blackberry, raspberry, and blueberry fruit rots to determine the causal organisms of fruit disease using both cultural and bioinformatics approaches. This approach also allows us to examine potential of causal pathogens for fungicide resistance. We confirmed that silver leaf of blueberry is occurring in commercial fields. Since this disease results in death of blueberry plants more extensive surveys are being conducted to determine the extent of the problem to Pacific Northwest Industry. To begin the research for Sub-objective 2E, we established a collection of fungicide resistant and sensitive isolates of Botrytis cinerea. This collection is being used to determine if aluminum salts have utility in managing Botrytis fruit rot and aid in reducing the threat of fungicide resistance development.

4. Accomplishments

Review Publications
Bailey, B.N., Mahaffee, W.F. 2017. Rapid, high-resolution measurement of leaf area and leaf orientation using terrestrial LiDAR scanning data. Measurement Science and Technology. 28(6):064006. doi: 10.1088/1361-6501/aa5cfd.
Miller, N., Stoll, R., Mahaffee, W.F., Pardyjak, E. 2017. Mean and turbulent flow statistics in a trellised agricultural canopy. Boundary Layer Meteorology. doi: 10.1007/s10546-017-0265-y.