Source: USDA, ARS, WHNRC submitted to
NEW DETECTION, RESEARCH, AND EXTENSION TOOLS FOR MANAGING WOOD-CANKER DISEASES OF FRUIT AND NUT CROPS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
OTHER GRANTS
Reporting Frequency
Annual
Accession No.
0229871
Grant No.
2012-51181-19954
Project No.
CALW-2012-01468
Proposal No.
2012-01468
Multistate No.
(N/A)
Program Code
SCRI
Project Start Date
Sep 1, 2012
Project End Date
Aug 31, 2017
Grant Year
2014
Project Director
Baumgartner, K.
Recipient Organization
USDA, ARS, WHNRC
430 WEST HEALTH SCIENCES DRIVE
DAVIS,CA 95616
Performing Department
(N/A)
Non Technical Summary
Wood-canker diseases significantly limit production and the longevity of grape, pistachio, and almond. With no eradicative controls, prevention is essential. This is attempted primarily through fungicides and preventative pruning, but grower adoption of such practices in mature vineyards and orchards comes too late for effective control. This is in spite of the fact that these diseases are widespread across the entire acreage of these crops and that these diseases are the main depreciable driver of crop longevity. Gaps in our ability to detect the pathogens in the nursery and the field, insufficient knowledge of disease-resistant cultivars, and a weak understanding of the socioeconomic factors that limit grower adoption of preventative practices contribute to a high disease incidence. Accordingly, we propose the following objectives: (i) to develop new detection tools for use by diagnosticians, nurserymen, and growers, (ii) to identify sources of resistance in the germplasm, and (iii) to encourage adoption of preventative control practices in young vineyards and orchards. These objectives are the main priorities for wood-canker disease research, as identified by an SCRI planning grant-funded series of meetings and workshops with an advisory board of commodity representatives, and with research and extension agents from across the US. Together, our goal is to combine innovative methodology and approaches to deliver sustainable and economically-feasible controls to effectively manage canker diseases in the orchard, vineyard, and nursery.
Animal Health Component
(N/A)
Research Effort Categories
Basic
50%
Applied
50%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2021139108010%
2021212108010%
2021219108010%
2021219108120%
2121139116010%
2121212116010%
2121219116010%
6011139301010%
6011219301010%
Knowledge Area
202 - Plant Genetic Resources; 212 - Pathogens and Nematodes Affecting Plants; 601 - Economics of Agricultural Production and Farm Management;

Subject Of Investigation
1212 - Almond; 1219 - Edible tree nuts, general/other; 1139 - Grapes, general/other;

Field Of Science
1080 - Genetics; 1160 - Pathology; 3010 - Economics; 1081 - Breeding;
Goals / Objectives
Our long-term goal is to develop effective wood-canker disease management strategies that improve the productivity and longevity of almond, grape, and pistachio. Wood-canker diseases are serious problems in perennial crops grown in Mediterranean climates of the US, Europe, Australasia, and South Africa, where the permanent, woody structure of the plant is maintained for many years without suffering freeze damage. Significant reduction in yields due to wood-canker diseases and the shortened lifespan of infected trees and vines mean that the high start-up costs for orchard and vineyard establishment are unlikely to be repaid over their shortened lives. California (CA) is the sole producer (i.e., greater than 99% of US production) of almonds, pistachios, and raisin grapes. CA leads the Nation in production of table grapes and wine grapes. To ensure their dominant position in the world marketplace, these US industries need to maintain a consistently high level of production and quality. Diseases that threaten the long-term viability of vineyards and orchards continually challenge this goal. Wood-canker diseases are among the most widespread and damaging problems in the Mediterranean regions of the US. Annual yield losses due to Eutypa dieback and Botryosphaeria canker, two of the most widespread wood-canker diseases of grape, account for 14% of the gross producer value, and this is just for wine grapes in CA. Annual yield losses of 20 million lbs. to Botryosphaeria canker are reported from pistachio in CA. In 2011, we were awarded an SCRI Planning Grant. In 2012, we submit this SREP, which was developed through two planning meetings, a three-day workshop, and numerous conference calls. Consensus was reached among industry, extension, and research participants on the following objectives: (i) Develop new detection tools for diagnosticians, growers, and nurseries, (ii) Identify disease-resistant cultivars and germplasm accessions, (iii) Develop and deploy new extension tools that increase adoption of preventative practices in young orchards and vineyards. These broad-ranging objectives address complex research questions that span cropping systems and intertwine the social and plant sciences. As such, these projects are not likely to be funded by commodity boards in annual grants to individual researchers. Out of the exhaustive list of topics that were considered, these three stood out as the most significant gaps in the knowledge, the absence of which hampers research on many smaller, shorter-term topics (e.g., testing control practices). Collectively, these objectives bring novel genetic, social, economic, and biological dimensions to research on wood-canker diseases, in order to make substantive advances.
Project Methods
Develop new detection tools: The internal nature of a wood-canker infection and the multi-year delay before symptoms appear limit our abilities to detect wood-canker diseases. We must wait for symptoms in the late stage of infection, but by then, it is too late to eradicate a wood infection. Nurseries are particularly vulnerable because the part of the plant that harbors the pathogen is their crop. Propagation materials (e.g., dormant cuttings) are inadvertently cut from apparently-healthy plants and sold to growers, who unknowingly plant with contaminated nursery stock. Nurseries do not have convenient methods for detecting the early stage of infection. Because symptoms can be ambiguous even at the late stage, wood-canker diseases are often misdiagnosed. Accordingly, we propose to develop new detection tools for diagnostic labs, nurseries, and growers. Encourage adoption of preventative practices: Wood-canker diseases significantly reduce crop longevity and necessitate replanting on a truncated cycle (e.g., 20 years for a typical CA vineyard). They affect every vineyard in CA and are the main depreciable driver of vineyard longevity. In pistachio, they attack the fruit. In almond, they attack the base of major limbs, and with the loss of one limb comes a reduction in 1/3 of the tree's crop. Despite these substantial consequences, growers routinely forego or incorrectly apply preventative practices. Consequently, they are overly reliant on more expensive measures taken later on (sawing off dead branches, replanting entire fields). Accordingly, we propose economic analyses and industry surveys to identify the socioeconomic factors that limit adoption. With a clear understanding of these factors, we will then build an effective outreach strategy with new tools for extension that encourage adoption of preventative practices soon after planting, rather than in mature vineyards and orchards, when it is too late. Identify disease-resistant plant material: Planting disease-resistant cultivars is a time-tested and sustainable approach to disease management. Based on field observations and published research on resistance to wood-canker diseases, we know that a range of resistance exists among commercial cultivars of almond and grape. We propose to improve screening assays for evaluating both commercial cultivars and USDA germplasm repositories for sources of disease resistance. In pistachio, the entire acreage of which consists of a single, susceptible cultivar, newly-released cultivars offer an opportunity for identifying new sources of resistance.

Progress 09/01/12 to 08/31/17

Outputs
Target Audience:The target audience consists primarily of grape, almond, and pistachio growers, and secondarily of experts who make recommendations to growers for disease management (pest-control advisers, diagnosticians, cooperative extension advisors). Communication with the target audience is facilitated primarily by national, state, and regional grower organizations. Grower organizations include: National Grape and Wine Initiative, Almond Board of California, California Pistachio Research Board, California Table Grape Commission, California Sustainable Winegrowing Alliance, Association for Applied IPM Ecologists, California Association of Pest Control Advisers, Lodi Winegrape Commission, and the Vineyard Team. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Trained licensed professionals involved with disease management, namely pest-control advisers and pesticide applicators, in diagnosis and management of trunk diseases. Efficiently communicated the benefits of early adoption by partnering with organizations that provide continuing-education courses, for e.g., California Assocation of Pest Control Advisers, Professional Association of Pesticide Applicators. Because pest-control advisers and pesticide applicators each have multiple growers as clients, more acreage is likely to benefit from early adoption, as opposed to communicating only with growers. Fostered international exchange between PIs and federal agencies of agricultural research in France (INRA) and New Zealand (New Zealand Institute for Plant and Food Research), through workshops in Davis, CA and contributed travel of graduate students to foreign labs. How have the results been disseminated to communities of interest?Established grower-relevant field demonstration of pruning-wound protectants, to encourage early adoption of this preventative practice, with a cash match from the California Table Grape Commission. Registered protectants [Luna Experience (Fluopyram + Tebuconazole, Bayer), Pristine (Pyraclostrobin, BASF), a mixture of Topsin (Thiophanate-methyl, United Phosphorus) and Rally (Myclobutanil, Dow AgroSciences), and Serifel (Bacillus amyloliquefaciens, BASF)] have neither been evaluated on table grapes nor through tractor-spray applications, and so this trial also serves an important research purpose. Building on the findings of our grape PCA survey, which revealed field trials as a top source of information for trunk-disease management, this field trial is a step toward encouraging early adoption. With participation by the local cooperative extension farm advisor in each step of the research, this field trial is an opportunity to inform our development of new extension tools targeting extension personnel. Efficiently communicated the benefits of early adoption with an instructional video on trunk-disease management (http://www.sustainablewinegrowing.org/educational-videos.php#34), produced by the California Sustainable Winegrowing Alliance with funding from the California Department of Food & Agriculture. Diverse prospectives from experts in plant pathology and agricultural economics, coupled with grower testimonials, support the need for preventative practices in all vineyards and instructions on how to carry them out. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Goal 1. Develop new detection tools for diagnosticians, growers, and nurseries. 1A) Detection of infected plants. Revealed a set of grape genes expressed in asymptomatic leaves in the early phase of infection, using Botryosphaeria-dieback pathogen Neofusicoccum parvum as a model to study host responses to a grapevine trunk disease. Further testing of this set of grape genes as a 'signature of infection', however, demonstrated a weak signal, which was detectable only during a narrow timespan and past this timespan was triggered by drought in the absence of infection. The focus, therefore, was shifted to an assay for infection of woody tissues, with higher expression of grape genes and alsopathogen genes. Such an assay would ne new tonurseries to screen mother plants and other propagation materials. Toward development of this assay, developed a DNA-sequence database for speciesdetection of the pathogens(www.TrunkDiseaseID.org), and sequenced the genomes and transcriptomes of six trunk pathogens. These study tools served as a foundation for unifying experiments on the composition of mixed infections in field samples. 1B) Spore traps for detection of trunk pathogens in young vineyards. Justified to grape growers the need for prevention of trunk diseases in young vineyards, based on detection of pathogen spores during winter rains. California vineyards eventually succumb to one or more trunk diseases (Esca, Botryosphaeria-, Eutypa-, and Phomopsis diebacks). Growers often neglect preventative measures (delayed pruning, applications of pruning-wound protectants, until the vineyard is mature and symptoms are widespread. To demonstrate that young vineyards are at risk of infection, spore traps were monitored after rain from winters of 2014-15 to 2016-17, in three young (2 to 5 yrs) and three mature (12 to 15 yrs) Cabernet-Sauvignon vineyards each in Napa and San Joaquin Counties of northern California. A higher frequency of detection of all pathogens late in the dormant season (February-March), with no apparent relationship to quantity of rain, suggests that if pruning is delayed to this time, a pruning-wound protectant should be applied before rain. Goal 2. Identify disease-resistant cultivars and germplasm accessions 2A) Identify molecular markers of grape resistance to Phomopsis dieback. Collaborated with SCRI project VitisGen to identify resistant breeding stock, thereby establishing a basis for future crosses directed at trunk-disease resistance. Phenotyped new hybrids, originally bred for cold-tolerant wine grapes (European cultivar Vitis vinifera 'Chardonnay' x North American species V. cinerea B9), for resistance to trunk disease Phomopsis dieback and foliar disease Phomopsis cane & leaf spot, both of which are caused by the pathogen Diaporthe ampelina (attacks green tissues during spring/summer rains, but attacks woody tissues- namely pruning wounds- during winter rains). Hybrid progeny segregated for resistance for a new cane-scarring phenotype on dormant canes under natural inoculum pressure in the field in Geneva, NY. Resistant and susceptible progeny (six of each), and both parents, showed consistent results for standard phenotypes on other tissues (spotting on green stems and internal lesions in woody stems) under controlled inoculations in two greenhouse experiments in Davis, CA. Identified novel qualitative resistance locus Rda1 from V. cinerea B9. Development of a molecular marker for Rda1 will facilitate selection of resistant genotypes from future breeding efforts. As acceptance of new cultivars in the table-grape industry is high, relative to wine grapes, this work accelerates the availability of resistant plant material as a long-term approach for trunk-disease management. 2B) Identify table grapes with resistance to Esca. Expanded the search for resistant grape germplasm to table grapes, with a focus on Esca, a common trunk disease in California's table-grape regions. Identified popular cultivars Flame Seedless and Scarlet Royal as resistant to Esca pathogen Phaeomoniella chlamydospora, especially compared to susceptible cultivar Thompson Seedless. The wood anatomy of Thompson Seedless, specifically its large xylem vessels, seems to be a predetermining factor of its susceptibility. Indeed, Flame Seedless and Scarlet Royal have smaller vessels, which may be a phenotype to screen for in breeding Esca-resistant table grapes. Established a field trial in a Scarlet Royal vineyard in the southern San Joaquin Valley (funded by a cash match from the California Table Grape Commission), to evaluate pruning-wound protectants, which will also help evaluate resistance of Scarlet Royal under field conditions to not only Esca, but the other trunk diseases. 2C) Identify almond cultivars with resistance to Band Canker. Developed new pathogenicity assays for the susceptible tissues and identified cultivars Butte and Monterey as resistant to the causal pathogens of Band Canker, Neofusicoccum parvum and N. nonquaesitum. These results under controlled assay conditions were consistent with field observations of resistance in Butte and Monterey, compared to susceptible cultivars Nonpareil, Padre, and Carmel. 2D) Identify causal agents of Trunk and Scaffold Cankers of almond. Identified pathogens Dothiorella iberica and Scytalidium dimitiatum, whereas seven other fungi were non-pathogenic (Diplodia seriata, N. parvum, N. nonquaesitum, Microphomina phaseolina, N. mediterraneum, B. dothidea, Dothiorella sarmentorum). Spore traps (microscope slides coated with vaseline) in symptomatic orchards identified the two pathogenic species, in addition to five other species (Diplodia seriata, D. corticola, Botryosphaeria viticola, N. mediterraneum, Diaporthe rhusicola). Similar to the trunk disease epidemiology in vineyards, fungal spores were released during winter rains. 2E) Identify pistachio cultivars with resistance to Panicle and shoot blight. Demonstrated the most widely planted cultivar, Kerman (90% of the California pistachio acreage) as the most resistant. This is based on a 3-yr study, in inoculations of mature trees with Panicle and shoot blight pathogens Botryosphaeria dothidea, Lasiodiplodia citricola, and Neofusicoccum mediterraneum. Moderately more susceptible were (in order of increasing susceptibility): Kaleghouchi, Aria, and Golden Hills. Red Aleppo was most susceptible. In inoculations of immature fruit and leaves in the laboratory, identified L. citricola as most virulent. Goal 3. Develop and deploy new extension tools that increase adoption of preventative practices in young orchards and vineyards Advanced the science on the benefits of early adoption to inform management of trunk diseases. Identified a major gap between published scientific data on practice efficacy and the social science of practice usage by revealing that grape pest-control advisers (PCAs) recommend preventative practices (which protect pruning wounds from infection) not for use on a preventative basis in young healthy vineyards, but instead more often in mature diseased vineyards. Results from grower surveys were consistent; most growers do not adopt preventative practices until after symptoms are widespread and the vineyard is 8+ years-old. Demonstrated the long-term impacts of taking no action vs. adopting preventative practices, using economic figures, which resonate more clearly with practitioners than infection data typically presented by researchers. Rapidly communicated research to practitioners through new online management plans (http://treeandvinetrunkdiseases.org/trunk-disease-management-in-california-preventative-practices-in-young-vineyards-post-infection-practices-in-mature-vineyards) and an economic decision tool (http://maxnorton.github.io/kaplan-model/). Expanded outreach on disease management to diagnostic labs, through a new DNA-sequence database for species-level detection of wood-colonizing fungi (www.TrunkDiseaseID.org).

Publications

  • Type: Journal Articles Status: Under Review Year Published: 2017 Citation: Lawrence DP, Travadon R, Baumgartner K. In review. Novel Seimatosporium species from grapevine in northern California and their interactions with fungal pathogens involved in the trunk-disease complex. Plant Disease.
  • Type: Journal Articles Status: Accepted Year Published: 2017 Citation: Morales-Cruz A, Allenbeck G, Figueroa-Balderas R, Ashworth VE, Lawrence DP, Travadon R, Smith RJ, Baumgartner K, Rolshausen P, Cantu D. In press. Closed-reference metatranscriptomics enables in planta profiling of putative virulence activities in the grapevine trunk disease complex. Molecular Plant Pathology. DOI 10.1111/mpp.12544.
  • Type: Journal Articles Status: Under Review Year Published: 2017 Citation: Barba P, Lillis J, Luce RS, Travadon R, Osier M, Baumgartner K, Wilcox WF, Reisch BI, Cadle-Davidson L. In review. Two dominant loci determine resistance to Phomopsis cane lesions in F1 families of hybrid grapevines. Theoretical and Applied Genetics.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Lawrence DP, Travadon R, Nita M, Baumgartner K. 2017. TrunkDiseaseID.org: A molecular database for fast and accurate identification of fungi commonly isolated from grapevine wood. Crop Protection 102: 110-117.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Massonnet M, Figueroa-Balderas R, Galarneau ERA, Miki S, Lawrence DP, Sun Q, Wallis CM, Baumgartner K, Cantu D. 2017. Neofusicoccum parvum colonization of the grapevine woody stem triggers asynchronous host responses at the site of infection and in the leaves. Frontiers in Plant Science 8:1117. DOI 10.3389/fpls.2017.01117.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Travadon R, Lecomte P, Diarra B, Lawrence DP, Renault D, Ojeda H, Rey P, Baumgartner K. 2016. Grapevine pruning systems and cultivars influence the diversity of wood-colonizing fungi. Fungal Ecology 24:82-93.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Bruez E, Baumgartner K, Bastien S, Travadon R, Guerin-Dubrana L, Rey P. 2016. Various fungal communities colonise the functional wood tissues of old grapevines externally free from grapevine trunk disease symptoms. Australian Journal of Grape and Wine Research 22:288-295.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Baumgartner K, Michailides T, Cantu D, Rolshausen P, Travadon R, Kaplan J, Nita M, Doll D, Lubell M, Wallis CM. 2017. Researchers and stakeholders shape advances in management of tree and vine trunk-disease complexes. Session on Success in SCRI, Annual Conference of the American Society for Horticultural Science, Waikoloa, Hawaii 9/19/17
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Baumgartner K. 2017. Different approaches for managing trunk diseases in young and mature vineyards. Professional Association of Pesticide Applicators, Napa, CA 8/29/17
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Wallis CM, Andrew LS, Rogers EE, Galarneau ER, Baumgartner K. 2017. Evolving phenolic roles in host defense: The cases of Candidatus Liberibacter solanacearum potato infections and that of grapevine pathogens. American Phytopathological Society Annual Meeting. San Antonio, TX. 8/5/17
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Lawrence DP, Travadon R, Nita M, Baumgartner K. 2017. TrunkDiseaseID.org: A molecular database for trunk pathogen diagnostics. International Workshop on Grapevine Trunk Diseases. Reims, France. 7/5/17
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Brown A, Lawrence DP, Baumgartner K. 2017. Wood-rotting basidiomycetes associated with grapevine trunk diseases in North America. International Workshop on Grapevine Trunk Diseases. Reims, France. 7/5/17
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Galarneau ER, Massonnet M, Lawrence DP, Travadon R, Wallis CM, Cantu D, Baumgartner K. 2017. Whole-plant defense during the early stage of infection to the wood-canker pathogen Neofusicoccum parvum (Botryosphaeria dieback). International Workshop on Grapevine Trunk Diseases. Reims, France. 7/5/17
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Brown A, Travadon R, Lawrence DP, Rolshausen P, Baumgartner K. 2017. Field-testing of pruning-wound protectants for trunk-disease management in California table grapes. American Phytopathological Society-Pacific Division Annual Meeting. Riverside, CA. 6/29/17
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Lawrence DP, Travadon R, Nita M, Baumgartner K. 2017. TrunkDiseaseID.org: A molecular database for grapevine trunk pathogen identification. American Phytopathological Society-Pacific Division Annual Meeting. Riverside, CA. 6/29/17
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Hillis V, Lubell M, Kaplan J, Baumgartner K. 2017. Preventative disease management and grower decision making: A case study of California wine-grape growers. Phytopathology 107:704-710.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Lawrence DP, Travadon R, Pouzoulet J, Rolshausen PE, Wilcox WF, Baumgartner K. 2017. Characterization of Cytospora isolates from wood cankers of declining grapevine in North America, with descriptions of two new Cytospora species. Plant Pathology 66:713-725. DOI 10.1111/ppa.12621.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Kaplan J, Travadon R, Cooper M, Hillis V, Lubell M, Baumgartner K. 2016. Identifying economic hurdles to early adoption of preventative practices: The case of trunk diseases in California winegrape vineyards. Wine Economics and Policy 5: 127-141.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Massonnet M, Morales-Cruz A, Figueroa-Balderas R, Lawrence DP, Baumgartner K, Cantu D. 2016. Condition-dependent co-regulation of genomic clusters of virulence factors in the grapevine trunk pathogen Neofusicoccum parvum. Molecular Plant Pathology. DOI 10.1111/mpp.12491.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Galarneau ERA, Wallis CM, Lawrence DP, Baumgartner K. 2017. Interaction of grapevine phenolic compounds and wood-colonizing fungi that cause grapevine trunk diseases. American Phytopathological Society-Pacific Division Annual Meeting. Riverside, CA. 6/29/17
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Baumgartner K, Hillis V, Fidelibus MW, Lubell M, Kaplan J. 2017. Encouraging table-grape growers to prevent trunk diseases through collaborative research with social scientists, extension specialists, and stakeholders. American Phytopathological Society-Pacific Division Annual Meeting. Riverside, CA. 6/29/17
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Fujiyoshi PT, Lawrence DP, Travadon R, Baumgartner K. 2017. Monitoring grapevine trunk diseases in young and mature vineyards in California wine regions. American Phytopathological Society-Pacific Division Annual Meeting. Riverside, CA. 6/29/17
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Travadon R, Mundy D, Baumgartner K. 2017. Developing a model system for studying the interactions between Vitis vinifera and Eutypa lata. American Phytopathological Society-Pacific Division Annual Meeting. Riverside, CA. 6/29/17
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Baumgartner K. 2017. Timing of spore release by vineyard trunk pathogens: Could spore trapping be used to identify and avoid periods of high infection risk? Napa Viticulture Technical Group, Napa, CA 2/1/17
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Baumgartner K. 2017. Trunk disease SCRI grant update. National Grape & Wine Initiative, Sacramento, CA 1/27/17
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Baumgartner K. 2016. Managing trunk diseases of grapevine. Sustainable Ag Expo, Vineyard Team, San Luis Obispo, CA 11/15/16
  • Type: Websites Status: Published Year Published: 2017 Citation: Lawrence DP, Travadon R, Nita M, Baumgartner K. 2017. TrunkDiseaseID.org: A molecular database for trunk pathogen diagnostics. http://TrunkDiseaseID.org
  • Type: Websites Status: Published Year Published: 2017 Citation: Kaplan J, Norton M, Baumgartner K. 2017. Trunk diseases management tool pilot website. http://treeandvinetrunkdiseases.org/economic-tool
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Luo Y, Gu S, Felts D, Puckett RD, Morgan DP, Michailides TJ. 2016. Development of qPCR systems to quantify shoot infections by canker-causing pathogens in stone fruits and nut crops. Journal of Applied Microbiology 122:416-428.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Michailides TJ, Morgan DP. 2016. Association of Botryosphaeria panicle and shoot blight of pistachio with injuries of fruit caused by Hemiptera insects and birds. Plant Disease 100:1405-1413.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Moral J, Ahimera N, Felts DG, Morgan DP, Michailides TJ. 2017. Effects of wound size, amount of sap, and number of blighted nuts on infection of pistachio organs by Neofusicoccum mediterraneum. Plant Disease 101: 2027-2033.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Michailides T. 2016. Pistachio and Walnut Disease Management. Syngenta Annual Meeting, Monterey, CA. 01/15/16.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Michailides T. 2016. Botryosphaeria in almonds and differences from Botryosphaeria in walnuts. Butte and Glenn Counties Almond Institute Meeting, Chico, CA. 02/05/16.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Michailides T. 2016. Botryosphaeria/Phomopsis canker and blights: Influence of El Nino on the sleeping giant. 47th Tri-County Walnut Day, Visalia. 02/04/16
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Michailides T. 2017. Pistachio Disease and their Management. Arizona Growers Meeting, Wilcox, AZ. 03/29/17.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Michailides T. 2017. Foliar disease update: Anthracnose and spray timings for Botryosphaeria. University of California Pistachio Workgroup, Coalinga, CA. 07/20/17.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Kaplan, J. 2017. Trunk Disease Prevention and Online Management Tool. California Sustainable Winegrowing Alliance, Ag Professional Day, Davis, CA. 6/16/17
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Kaplan, J. 2017. Benefits of Preventative Pruning Practices in Managing Grapevine Trunk Diseases. Sonoma County Winegrape Commission Field Day, Shone Farms, Guerneville, CA. 4/25/17.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Kaplan, J. 2017. Economic hurdles to early adoption of grapevine trunk disease preventative practices. Virginia Vineyards Association Winter Technical Meeting, Charlottesville, VA. 2/24/17.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Kaplan, J. 2016. Economic hurdles to early adoption of grapevine trunk disease preventative practices. Sustainable Ag Expo, Vineyard Team, San Luis Obispo, CA. 11/15/16.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Kaplan, J. 2016. Extension Tools for Managing Grapevine Trunk Diseases. National Grape and Wine Initiative Annual Board Meeting, Sacramento, CA. 9/27/16.
  • Type: Journal Articles Status: Under Review Year Published: 2017 Citation: Pouzoulet J, Pivovaroff AL, Scudiero E, De Guzman M, Rolshausen PE, Santiago LS. 2017. Contrasted xylem adaptation to drought stress sub-species. American Journal of Botany: Under Review.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Pouzoulet J, Scudiero E, Schiavon M, Rolshausen PE. 2017. Xylem vessel diameter affects the compartmentalization of the vascular pathogen Phaeomoniella chlamydospora in grapevine. Frontiers in Plant Science 8: 1442.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Paolinelli-Alfonso M, Villalobos-Escobedo JM, Rolshausen PE, Herrera-Estrella A, Galindo-Sanchez C, Lopez-Hernandez JF, Hernandez-Martinez R. 2016. Global transcriptional analysis suggests Lasiodiplodia theobromae pathogenicity factors involved in modulation of grapevine defensive response. BMC Genomics: DOI 10.1186/s12864-016-2952-3.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Pouzoulet J, Scudiero E, Schiavon M, Rolshausen PE, 2017. New insights in the vessel diameter mediated resistance toward Esca disease of grapevine. International Workshop on Grapevine Trunk Diseases. Reims, France. 7/5/17
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Rolshausen PE. 2017. Grapevine trunk disease management. California Association of Pest Control Advisers. 2017 Spring Summit, Temecula, CA. 4/25/17


Progress 09/01/14 to 08/31/15

Outputs
Target Audience:The target audience consists primarily of grape, almond, and pistachio growers, and secondarily of experts who make recommendations to growers for disease management (pest control advisors, diagnosticians, cooperative extension advisors). Communication with the target audience is facilitated primarily by national, state, and regional grower organizations. Examples of specific grower organizations include the National Grape and Wine Initiative, Almond Board of California, California Pistachio Research Board, California Table Grape Commission, Association for Applied IPM Ecologists, California Association of Pest Control Advisors, the Lodi Winegrape Commission, and the Vineyard Team. Changes/Problems:Goal 1. Develop new detection tools for diagnosticians, growers, and nurseries. 1A) Identify a molecular signature for the early stage of Botryosphaeria dieback. In the event that the N. parvum-specific molecular signature ends up having too few markers, after weeding out the markers that cross react with drought stress, other trunk pathogens, or are not expressed in other grape cultivars, our contigency plan is to go back to the list of differentially-expressed genes, which we originally identified in 2014 by comparing the RNAseq transcriptome sequences of leaves from inoculated versus non-inoculated Cabernet Sauvignon. With hundreds of such genes to choose from, there are additional candidates we can screen for N. parvum-specificity. As we have the RNA from all three experiments (water stress, multiple trunk pathogens, multiple cultivars), testing for new markers would go quickly. What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest?Goal 3. Develop and deploy new extension tools that increase adoption of preventative practices in young orchards and vineyards. 3A) Benefits of early adoption. In cooperation with the California Table Grape Commission, we established a field trial to demonstrate the use of pruning-wound protectants myclobutanil (Rally) and thiophanate-methyl (Topsin) in a young table-grape vineyard in the southern San Joaquin Valley. These products have neither been evaluated on table grapes nor through tractor spray applications, and so this trial also serves an important research purpose. This young Red globe vineyard has no symptoms of trunk diseases, but surrounding mature blocks have a high incidence of Eutypa and Botryosphaeria diebacks. In treated and nontreated rows, we will examine symptom development each year. Building on the findings of our grape PCA survey (see What was accomplished under these goals? 3A. Benefits of early adoption), which revealed that PCAs rank field trials in the top three most-preferred sources of information for trunk-disease management, we see this as a step toward encouraging growers to adopt preventative practices in young vineyards. The study site will be included in our spore-trapping study (see What was accomplished under these goals? 1B. Develop spore traps for detection of trunk pathogens in young vineyards), with a future goal of using spore trapping to time trunk-disease management in table-grape vineyards. With the participation of local extension advisors, all of whom are new hires, this field trial will be an opportunity to inform our development of new extension tools for extension advisors (see What do you plan to do during the next reporting period to accomplish these goals? 3A. Benefits of early adoption). In cooperation with Washington State University Cooperative Extension, we published an article for growers on the economic benefits of preventing trunk diseases in Washington winegrape vineyards (http://wine.wsu.edu/research-extension/files/2010/07/2014-Fall-VEEN-Final.pdf). The article focused on double pruning, a technique used by a much higher proportion of growers in Washington, compared to California. With a higher risk of winter injury in Washington, the 1st pass of double pruning provides sufficient canes in case buds are killed before the 2nd and final pass. We compared double pruning to applications of pruning-wound protectants. In this way, we adapted our research to a new production area in the US. In cooperation with the Sonoma County Winegrape Commission (Santa Rosa, California), we provided technical information for an instructional video for growers on trunk-disease management, produced by the Commission. The charts we included in the video, which are similar to those in an online article we published this year with the Lodi Winegrape Commission (http://www.lodigrowers.com/making-a-case-for-early-adoption-of-practices-to-prevent-trunk-diseases/), very clearly display how as disease incidence increases, yield losses compound over time. After 25 years, greater economic gains are predicted, the earlier preventative practices are adopted. These were combined in the 10-minute video with descriptions of the disease cycle and demonstrations of practices in the vineyard (preventative practices delayed pruning and double pruning, post-infection practices retraining and sanitation). In cooperation with University of California Cooperative Extension, we surveyed grape growers on the annual costs of preventative practices. Cooperating viticulture advisors, many of whom were on our Survey Advisory Board, shared in the development of this online cost survey and were responsible for its distribution. The survey results filled in gaps in our economic model. More importantly, the process revealed that there is a range of knowledge on trunk-disease management among the advisors, which includes many new hires and advisors with responsibilities for multiple crops. No extension tools target this group. What do you plan to do during the next reporting period to accomplish the goals?Goal 1. Develop new detection tools for diagnosticians, growers, and nurseries. 1A) Identify a molecular signature for the early stage of Botryosphaeria dieback. We will confirm the specificity of the molecular signature to N. parvum by testing for possible interactive effects with foliar diseases Powdery mildew and Phomopsis cane & leaf spot. This will be the last in a series of greenhouse experiments to test marker specificity. The next step will be to test field samples. 1B) Develop spore traps for detection of trunk pathogens in young vineyards. Spore trapping will continue this winter, hopefully with more rain. In the meantime, we will test the specificity of new markers for aggressive isolates of N. parvum, T. minima, P. chlamydospora, E. lata, and D. ampelina. To facilitate precise detection of related pathogens of tree crops, we will sequence the genomes of trunk pathogens of pistachio and almond (namely, species in the fungal family Botryosphaeriaceae). Goal 2. Identify disease-resistant cultivars and germplasm accessions 2A) Identify molecular markers of grape resistance to Phomopsis dieback (VitisGen collaboration). We will determine if foliar symptoms of Phomopsis cane & leaf spot correlate with expression of markers physically linked to Rda1, in a replication of D. ampelina inoculations to progeny of the cross of V. cinerea B9 x V. vinifera Chardonnay clone 95. As all progeny are maintained in the field in Geneva, NY under natural (variable) disease pressure, we established a clean set of greenhouse plants for controlled inoculations. V. cinerea B9 does not propagate from dormant cuttings; Andy Walker (University of California, Davis) has offered valuable assistance propagating from green cuttings. In 2016, we will propagate plants for stem inoculations in 2017, to test for resistance to Phomopsis dieback. 2B) Identify table grapes with resistance to Botryosphaeria dieback. We will determine the relative resistance, based on lesion lengths at 3 months post-inoculation, of table-grape cultivars Autumn king, Crimson seedless, Fantasy, Flame seedless, Red globe, Scarlet royal, and Thompson seedless to N. parvum, in a replication of the 2015 greenhouse experiment. 2C) Identify anatomical and biochemical markers of grape resistance to Esca, Eutypa dieback, and Botryosphaeria dieback. We will measure wood chemical composition including lignin content and polymer structure (linkages, syringyl to guaiacyl ratios) total charbohydrate content, and sugar content (glucan, mannan galactan, xylan, arabinan) to determine if parameters differ significantly among cultivars Merlot, Cabernet Sauvignon, and Thompson seedless, and if differences in wood chemistry correspond to resistance (as measured in terms of lesion lengths) to Esca, Eutypa dieback, and Botryosphaeria dieback. This approach will be applied to new hosts - almond and pistachio (see 2D and 2F below). 2D) Identify almond cultivars with resistance to Bank canker. We will repeat field inoculations of N. nonquesitum, N. parvum, and N. mediterraneum to mature trees of Butte, Carmel, Padre, and Nonpareil. In the greenhouse, we will inoculate the same fungi to five new cultivars: Avalon, Marcona, Superiel, Winters, and Wood colony. In addition to the standard measure of resistance (lesion length), we will measure xylem vessel diameter and wood chemistry parameters, to determine if they correspond to lesion length and can potentially be considered as anatomical and biochemical markers of resistance (see 2C above). 2E) Identify causal agents of trunk and scaffold cankers of almond. We will replicate spore trapping at the three symptomatic orchards, to confirm results from the previous two winters. The orchards are now being used to test pruning-wound treatments for protection against infection by N. nonquesitum, N. parvum, and N. mediterraneum, through post-application inoculation of spore suspensions, as has been shown to be effective for trunk pathogens of grape. Outside the areas of testing, the orchard blocks have been and will continue to be surveyed for symptom severity. 2F) Identify pistachio cultivars with resistance to Panicle and shoot blight. The 3rd and last replication of the experiment will be repeated by inoculating (in the field and the laboratory) B. dothidea, L. citricola, and N. mediterraneum to all commercial cultivars of pistachio [Kerman (susceptible) vs. newly-released cultivars Kalehghuchi, Lost Hills (resistant), Golden Hills (resistant), Aria, Red Aleppo, Peters, Randy, and Joley]. We will determine if differences in the incidence of latent infection of immature fruit relate to differences in resistance, based on panicle and shoot blight incidence at harvest. In addition to this standard measure of resistance, we will measure xylem vessel diameter and wood chemistry parameters, to determine if they correspond to incidence of panicle and shoot blight and can potentially be considered as anatomical and biochemical markers of resistance (see 2C above). To identify potential new sources of resistance in the pistachio germplasm, we will continue surveys of the USDA-ARS National Clonal Germplasm Repository in Davis, CA. Goal 3. Develop and deploy new extension tools that increase adoption of preventative practices in young orchards and vineyards. 3A) Benefits of early adoption. Extension tools for PCAs and cooperative extension advisors will be developed to communicate the importance of timing practices according to disease incidence. As these two groups of professionals work regularly with growers, it is a more efficient outreach strategy for communicating our message of adopting preventative practices before symptoms appear. We will also develop an interactive web-based economic decision-support tool for growers to evaluate adoption of preventative practices. We will develop an on-line database for identification of wood-colonizing fungi of grape, almond, and pistachio, for use primarily by diagnostic labs and secondarily by researchers. This sequence database will be based on culture collections in the Baumgartner, Michailides, and Rolshausen labs. The database will be searchable on our project website treeandvinetrunkdisease.org, using the BLAST algorithm. It will also serve as a depository for sequences of newly-described species. Although there are many sequences of trunk pathogens on the public database GenBank, not all entries are accurate and evaluating their accuracy requires very specialized expertise, which many diagnostic labs do not have.

Impacts
What was accomplished under these goals? Goal 1. Develop new detection tools for diagnosticians, growers, and nurseries. 1A) Identify a molecular signature for the early stage of Botryosphaeria dieback. To detect the presence of Neofusicoccum parvum in asymptomatic plants, we developed molecular markers from grapevine genes, which are expressed in leaves during the pathogen's latent phase. To ensure that this molecular signature does not also detect drought, we subjected inoculated and non-inoculated Cabernet Sauvignon plants to water stress (leaf water potential -13 to -15 bars) and maintained half of the plants with adequate water (> -8 bars). After 3 months, water stress visibly limited plant growth and exacerbated lesion length. Some markers were detected only in leaves of inoculated plants, but others were detected also in stressed plants; this latter set of markers is thus not specific to N. parvum. We are testing specificity of the N. parvum molecular signature against other trunk diseases (Botryosphaeria dieback pathogen Diplodia seriata, Eutypa dieback pathogen Eutypa lata, or Esca pathogen Phaeomoniella chlamydospora) in Cabernet Sauvignon plants. We have a 3rd experiment to test levels of expression of the N. parvum molecular signature in cultivars Merlot (resistant), Cabernet Sauvignon (moderate), and Thompson seedless (susceptible). These greenhouse experiments will be completed September 2016. 1B) Develop spore traps for detection of trunk pathogens in young vineyards. For a 2nd year, we compared the Rotorod trap (used commercially for detection of grapevine powdery mildew) to microscope slides coated in vaseline (used by researchers). Spore traps were set in three young (3-5 years-old, asymptomatic) and three mature (13-15 years-old, symptomatic) vineyards, each in Napa and San Joaquin Counties of northern California, and were retrieved within 24 h of rain. This year we added moisture sensors to the Rotorod traps, to make them spin automatically with rain and thus to minimize inhibitors from the many things that stick to them. With only four suitable rain events, however, comparisons of vineyard age, trap type, and detection method were impossible. Culture-based recovery (similar for both traps) detected one instance ofN. parvum and oneinstance of Diaportheampelina. DNA-based detection found only one instance: P. chlamydosporafrom a slide. No E. lata was detected with either method. To improve the precision of DNA-based detection, while waiting for rain, we sequenced the genomes of Phomopsis dieback pathogen Diaporthe ampelina and Esca pathogens Togninia minima and Phaeomoniella chlamydospora. Goal 2. Identify disease-resistant cultivars and germplasm accessions 2A) Identify molecular markers of grape resistance to Phomopsis dieback (VitisGen collaboration). Qualitative resistance locus Rda1 was identified from Vitis cinerea B9, a source of resistance to Phomopsis cane & leaf spot, by Lance Cadle-Davidson (USDA-ARS, Geneva, NY) and Bruce Reisch (Cornell University, Geneva, NY). D. ampelina causes both Phomopsis cane & leaf spot and Phomopsis dieback. Field observations of scarring on dormant canes revealed that progeny from a cross of V. vinifera Chardonnay clone 95 x V. cinerea B9 segregated 3:1 for little to no scarring (resistant phenotype). We are propagating resistant and susceptible progeny (five each) and the parents (both resistant), to confirm correspondence between the phenotype observed in the field and foliar lesions, a phenotype observed in the greenhouse. This greenhouse experiment will be completed in 2016. Our next step is to determine if Rda1 is a marker of resistance to Phomopsis dieback. 2B) Identify table grapes with resistance to Botryosphaeria dieback. We inoculated N. parvum to woody stems of table-grape cultivars Autumn king, Crimson seedless, Fantasy, Flame seedless, Red globe, Scarlet royal, and Thompson seedless (susceptible). We will measure lesion lengths and determine if this standard measure of resistance corresponds to wood anatomical and biochemical features (see 2C below). This greenhouse experiment will be completed September 2015. 2C) Identify anatomical and biochemical markers of grape resistance to Esca, Eutypa dieback, and Botryosphaeria dieback. We determined that diameter of xylem vessels, the main cells colonized by P. chlamydospora, corresponds to lesion length, a standard measure of resistance, but one that takes up to a year to measure. Vessel diameter increased with increasing lesion length in Merlot (resistant), Cabernet Sauvignon (moderate), and Thompson seedless (susceptible). To test vessel diameter as a potential anatomical marker of other trunk diseases, we inoculated these same cultivars with E. lata and N. parvum. To test vessel diameter as a potential anatomical marker of Esca resistance, we inoculated P. chlamydospora to table-grape cultivars Autumn king, Crimson seedless, Fantasy, Flame seedless, Red globe, Scarlet royal, and Thompson seedless. These greenhouse experiments will be completed in 2016. 2D) Identify almond cultivars with resistance to Bank canker. We inoculated N. nonquesitum and N. parvum to woody stems of cultivars Butte, Carmel, Fritz, Mission, Monterey, Nonpareil, Padre, Peerless, Price, and Sonora. We will measure lesion lengths and determine if this standard measure of resistance corresponds to wood anatomical and biochemical features (see 2C above). This greenhouse experiment will be completed in September 2015. 2E) Identify causal agents of trunk and scaffold cankers of almond. We identified Dothiorella iberica and Scytalidium dimitiatum as pathogenic, through inoculations to mature almond trees of these and seven other fungi, which were non-pathogenic (Diplodia seriata, N. parvum, N. nonquesitum, Microphomina phaseolina, N. mediterraneum, B. dothidea, Dothiorella sarmentorum). Spore traps (microscope slides coated with vaseline) in symptomatic orchards identified the two pathogenic species, in addition to five other species (Diplodia seriata, D. corticola, Botryosphaeria viticola, N. mediterraneum, Diaporthe rhusicola). 2F) Identify pistachio cultivars with resistance to panicle and shoot blight. In year 2 of a 3-yr study, in inoculations of mature trees with Botryosphaeria dothidea, Lasiodiplodia citricola, and N. mediterraneum, we again found Kerman (90% of the acreage, susceptible) was most resistant. Moderately more susceptible were (in order of increasing susceptibility): Kaleghouchi, Aria, and Golden Hills. Red Aleppo was by far most susceptible. In inoculations of immature fruit and leaves in the laboratory, L. citricola was most virulent. Field and laboratory experiments agree: Kerman is most resistant. Preliminary results (experiments will be repeated in 2016), suggest none of the new cultivars are better. Goal 3. Develop and deploy new extension tools that increase adoption of preventative practices in young orchards and vineyards 3A) Benefits of early adoption. A survey of grape pest control advisors (PCAs) opened our eyes to one major detail missing from extension tools on trunk-disease management: use preventative practices BEFORE you see symptoms. Because of the long disease cycles, many growers rely more on socially-obtained information than on 'trial-and-error' to make decisions about trunk-disease management. Rather than survey growers, therefore, we surveyed their PCAs, specifically on their recommendations and perceptions of preventative practices (delayed pruning, double pruning, pruning-wound protectants) and post-infection practices (retrain cordon, retrain trunk, replant specific vines, replant whole block, sanitation). The online survey revealed that PCAs are aware of the risk of trunk diseases, and they perceive the practices as effective. However, they recommend all practices more often in vineyards with high disease prevalence; preventative practices were not recommended more in young vineyards (with low disease prevalence).

Publications

  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Baumgartner K. 2015. Bridging the gaps between scientific literature and grower perceptions of trunk disease management. Sustainable control of grapevine trunk diseases: Current state and future prospects (COST Action FA 1303), Cognac, France. 6/24/15
  • Type: Websites Status: Published Year Published: 2015 Citation: Mustacich, S. 2015. A Dire Threat to Grapevines: Esca and other vine trunk diseases are infecting vines aroung the globe, threatening an epidemic. Wine Spectator Magazine. http://www.winespectator.com/webfeature/show/id/51972?utm_source=internal&utm_medium=link&utm_campaign=most_popular
  • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Baumgartner K, Czemmel S, Cramer GR, Galarneau ER, Travadon R, Lawrence DP, McElrone AJ, Cantu DA. 2014. Plant-based markers of infection for Neofusicoccum parvum. 9th International Workshop on Grapevine Trunk Diseases. Adelaide, South Australia. 11/18/14.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Baumgartner K, Doll D, Hillis AV, Kaplan J, Lubell M. 2015. The role of pest control advisors in managing grapevine trunk diseases: a survey of perceptions of practice efficacy and trends in recommendations. American Phytopathological Society Annual Meeting. Pasadena, CA. 8/5/15.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Baumgartner K, Kaplan JD, Travadon R, Cooper M, Hillis AV, Lubell M. 2014. An economic case for early adoption of preventative practices for management of grapevine trunk diseases. 9th International Workshop on Grapevine Trunk Diseases. Adelaide, South Australia. 11/18/14.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Baumgartner K, Kaplan J. 2014. Benefits from management of trunk diseases of grapevines. Wine Economics Research Symposium: Bordeaux and Davis, Department of Agricultural and Resource Economics, University of California, Davis, CA. 10/20/14
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Baumgartner K. 2015. Detection of virulent trunk pathogens. Current Wine and Wine Grape Research, University of California Extension, Davis, CA. 2/9/15
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Baumgartner K. 2015. Grapevine trunk diseases in California vineyards. California Association of Pest Control Advisors, San Jose, CA. 5/6/2015
  • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Baumgartner K. 2014. Managing trunk diseases in table grapes. University of California Cooperative Extension, Coachella, CA. 10/30/14
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Baumgartner K. 2015. Managing trunk diseases of grapevines. Southern Oregon Grape Symposium, Rogue Valley Winegrowers Association, Central Pointe, OR. 3/16/15
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Baumgartner K. 2015. Modelling the economics and efficacy of early adoption of preventative practices for managing trunk diseases. Australian Society for Viticulture and Oenology, Mildura, Victoria, Australia. 7/22/15
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Baumgartner K. 2015. Preventing trunk diseases: Economic analysis and grower surveys. Napa Viticulture Technical Group, Napa, CA. 1/14/15
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Baumgartner K. 2015. Shifting grower perspectives on trunk disease management with multi-disciplinary research and new approaches to outreach. National Viticulture and Enology Extension Leadership Conference, Lodi, CA. 3/26/15
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Travadon R, LeComte P, Diarra B, Lawrene DP, Vallance J, Ojeda H, Rey P, Baumgartner K. 2015. Influence of pruning systems on trunk pathogens and other fungi colonizing grapevine wood. American Phytopathological Society Annual Meeting. Pasadena, CA. 8/4/15.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Travadon R. 2015. New detection, research, and extension tools for managing wood canker diseases. National Viticulture and Enology Extension Leadership Conference, Lodi, CA. 3/24/15.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Baumgartner K. 2015. The economic benefits of preventing trunk diseases in young vineyards. E & J Gallo Winery, Modesto, California. 7/8/15
  • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Travadon R, Preece JE, Baumgartner K, 2014. Evaluating grapevine germplasm for resistance to Eutypa dieback. 9th International Workshop on Grapevine Trunk Diseases. Adelaide, South Australia. 11/20/14.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Doll D. 2015. Botryospaeriaceae wood cankers of almond: timing of infections and potential management. Wilbur Ellis Pest Control Advisor Meeting. Modesto, CA. 11/5/15.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Doll D. 2015. Pruning wound cankers of almond: should I wait to prune? Merced County Pest Management Update. Merced, CA. 2/24/15.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Michailides TJ. 2014. Foliar diseases, including Botryosphaeria panicle and shoot blight) of pistachio. Pistachio Short Course, Visalia. 11/19/2014
  • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Michailides TJ. 2014. Identifying sources of resistance in pistachio and almond; resistance of new and commercial cultivars. Davis, California. 12/3/14
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Michailides TJ. 2015. Update on pistachio diseases. 2015. Syngenta Winter Customer Meeting. Coalinga, California, 1/15/15
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Michailides TJ. 2015. Pistachio and walnut diseases and pest management of Botryosphaeria, Alternaria, and Botrytis. 2015 Bayer Crop Science Winter Symposium. Monterey, California. 1/17/15
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Moral J, Perez-Rodriguez M, Michailides TJ, Trapero A. 2015. 2015. First report of the teleomorph of Neofusicoccum mediterraneum, a pathogen of olive. American Phytopathological Society Annual Meeting. Pasadena, CA. 8/3/15.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Michailides TJ. 2015. Update on foliar and fruit diseases of pistachio. 2015 Statewide Pistachio Day. Visalia, California. 1/21/15
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Michailides TJ. 2015. Pistachio diseases: Diagnosis and demostration. Statewide Pistachio Day, Integrated Pest Management for Pistachio. Visalia, California. 1/21/15
  • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Klinger G, Nita M. 2014. The occurrence and distribution of grape-pathogenic Botryosphariaceae fungi in nursery stocks. 90th annual Cumberland-Shenandoah Fruit Workers Conference, Winchester, VA. 9/1/14
  • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Lawrence DP, Fujiyoshi PT, Travadon R, Cantu D, Morales-Cruz A, Rolshausen PE, and Baumgartner K. 2014. Detection of trunk pathogen inoculum in young vineyards to encourage adoption of preventative practices. 9th International Workshop on Grapevine Trunk Diseases. Adelaide, South Australia. 11/18/14.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Lawrence DP, Galarneau ER, Travadon R, and Baumgartner K. 2015. Interactive effects of water stress and Neofusicoccum parvum on Botryosphaeria dieback of grapevines. Annual meeting of the American Phytopathological Society, Pasadena, CA. POSTER. 8/4/15.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Travadon R, Lecomte P, Diarra B, Lawrence DP, Renault D, �jeda H, Rey P, and Baumgartner K. 2015. Comparisons of fungal trunk pathogens and endophytic fungi between minimally pruned and spur-pruned vines in southern France. 19th GiESCO (International Group of Experts in wine systems for cooperation), Gruissan, France. POSTER. 6/5/15.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Lawrence DP, Travadon R, Rooney-Latham S, Gubler WD, Wilcox WF, Rolshausen PE, and Baumgartner K. 2014. The role of Cadophora species as trunk pathogens in North American grape-growing regions. 9th International Workshop on Grapevine Trunk Diseases, Adelaide, South Australia. POSTER. 11/18/14.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Morales-Cruz A, Amrine KCH, Lawrence DP, Travadon R, Baumgartner K, Rolshausen PE, and Cantu DA. 2014. Genomics of grapevine trunk diseases. 9th International Workshop on Grapevine Trunk Diseases, Adelaide, South Australia. POSTER. 11/18/14.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Cantu D. 2014. Genomic tools for viticulture. E.J. Gallo Technical Seminars. E.J. Gallo winery. Modesto, CA. 12/08/14.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Cantu D, Morales-Cruz A, Jones L, Blanco-Ulate B, Amrine KCH, Riaz S, Walker MA, Rolshausen PE, Baumgartner K. 2015. A pathogenomic approach to decipher the molecular mechanisms underlying grapevine diseases. Plant and Animal Genome XXIII Conference. San Diego, CA. 1/11/15.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Cantu D. 2015. Pathogenomics and systems biology of grapevine diseases. Monsanto. Woodland, CA. 5/19/15.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Cantu D. 2015. Pathogenomics and systems biology of grapevine diseases. International meeting in Plant Biotechnology: Plant Stress and Sustainable Agriculture. Santiago, Chile. 6/30/15.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Hillis V, Baggio J. 2014. Social learning and the diffusion of crop disease prevention strategies; an agent-based model. Conference on Complex Systems. Tempe, AZ. 11/2/14.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Hillis V, Baggio J. 2015. A cultural evolutionary model of crop disease prevention in a networked social-agroecological system. 15th Biennial Global Conference of the International Association for the Study of the Commons. Edmonton, Canada. 5/25/15.
  • Type: Journal Articles Status: Awaiting Publication Year Published: 2015 Citation: Bruez E, Baumgartner K, Bastien S, Travadon R, Guerin-Dubrana L, Rey P. In press. Various fungal communities colonize the functional wood tissues of old grapevine trunk disease-asymptomatic vines. Australian Journal of Grape and Wine Research.
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Czemmel S, Galarneau ER, Travadon R, McElrone AJ, Cramer GR, Baumgartner K. 2015. Genes expressed in grapevine leaves reveal latent wood infection by the fungal pathogen Neofusicoccum parvum. PLoS ONE 10: e0121828. DOI 10.1371/journal.pone.0121828
  • Type: Journal Articles Status: Awaiting Publication Year Published: 2015 Citation: Lawrence DP, Travadon R, Baumgartner K. In press. Diversity of Diaporthe species associated with wood cankers of fruit and nut crops in northern California. Mycologia
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Morales-Cruz A, Amrine KCH, Blanco-Ulate B, Lawrence DP, Travadon R, Rolshausen P, Baumgartner K, Cantu D. 2015. Distinctive expansion of gene families associated with plant cell wall degradation, secondary metabolism, and nutrient uptake in the genomes of grapevine trunk pathogens. BMC Genomics 16: 469. DOI 10.1186/s12864-015-1624-z
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Travadon R, Baumgartner K. 2015. Molecular polymorphism and phenotypic diversity in the generalist, wood decay fungus Eutypa lata. Phytopathology 105: 255-264.
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Travadon R, Lawrence DP, Rooney-Latham S, Gubler WD, Rolshausen PE, Baumgartner K. 2015. Cadophora species associated with wood decay of grapevine in North America. Fungal Biology 119: 53-66.
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Doll DA, Rolshausen PE, Pouzoulet P, Michailides TJ. 2015. First report of Dothierella iberica causing trunk and scaffold cankers of almond in California. Plant Disease 99:1185.
  • Type: Journal Articles Status: Awaiting Publication Year Published: 2015 Citation: Chen SF, Li GQ, Liu FF, Michailides TJ. In press. Novel species of Botryosphaeriaceae associated with shoot blight of pistachio in California. Mycologia.
  • Type: Journal Articles Status: Under Review Year Published: 2015 Citation: Hillis V, Lubell M, Kaplan J, Doll D, Baumgartner K. In review. The role of pest-control advisors in the under-adoption of preventative trunk disease-management practices in California vineyards. Agriculture, Ecosystems and Environment.
  • Type: Websites Status: Published Year Published: 2015 Citation: Baumgartner K, Kaplan J, Travadon R, 2015. Making the economic case for early adoption of practices to prevent trunk diseases. Lodi Winegrape Commission, http://www.lodigrowers.com/making-a-case-for-early-adoption-of-practices-to-prevent-trunk-diseases/ (posted 3/16/15)
  • Type: Websites Status: Published Year Published: 2015 Citation: Kaplan J, Travadon R, Baumgartner K. 2014. Double pruning to prevent trunk diseases in Washington vineyards. Viticulture and Enology Extension News, Fall 2014, Washington State University. http://wine.wsu.edu/research-extension/files/2010/07/2014-Fall-VEEN-Final.pdf


Progress 09/01/13 to 08/31/14

Outputs
Target Audience: The target audience consists primarily of grape, almond, and pistachio growers, and secondarily of consultants associated with the production of these crops (e.g., pest control advisors, diagnosticians). Communication with the target audience is facilitated by national, state, and regional grower organizations and by cooperative extension agents throughout the US. Examples of specific grower organizations include the National Grape and Wine Initiative, Almond Board of California, California Pistachio Research Board, California Table Grape Commission, Association for Applied IPM Ecologists, California Association of Pest Control Advisors, the Lodi Winegrape Commission, and the Vineyard Team. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? A strong foundation for interaction with stakeholders is the Survey Advisory Board, which consists of regional grower groups, extension agents, and some Industry Advisory Board members. These partnerships made for very efficient surveys in 2012-2014, and will serve as a ‘channel’ for new extension tools and the follow-up survey in 2016. What do you plan to do during the next reporting period to accomplish the goals? Goal 1. Develop new detection tools for diagnosticians, growers, and nurseries. A molecular signature for the early stage of Botryosphaeria dieback. Confirm the molecular signature of N. parvum infection is specific and that markers are not amplified in plants stressed by drought, infected by other trunk pathogens (Togninia minima, Eutypa lata), or foliar diseases (Powdery mildew, Bunch rot). spore traps for trunk pathogens in young vineyards. We expect a delay between rain-induced spore production and infection, which would provide a ‘window’ for growers to apply protective fungicides. We will determine if spore trapping provides enough time to apply a protectant before spores infect pruning wounds. Goal 2. Identify disease-resistant cultivars and germplasm accessions FOR GRAPE: 1) Identify markers of resistance to Eutypa dieback. Compare expression profiles of nine candidate genes between resistant cultivars ‘Merlot’ and ‘Primitivo’, and susceptible cultivars ‘Black Corinth’ and ‘Husseine’. Also, determine if Merlot and Primitivo have small xylem vessels and high lignin content (putative anatomical and biochemical markers of resistance), and if Black Corinth and Husseine have wide xylem vessels and low lignin content. FOR PISTACHIO: 1) Identify pistachio cultivars with resistance to Panicle blight. Repeat inoculations of B. dothidea, L. citricola, and N. mediteraneum to commercial cultivars [Kerman (susceptible) vs. newly-released cultivars Kalehghuchi, Lost Hills (resistant), Golden Hills (resistant), Aria, Red Aleppo, Peters, Randy, and Joley]. Measure xylem vessel diameter and lignin content (see #1 for grape). 2) Determine if differences in latent infection of immature fruit correlate with differences in resistance to Panicle blight. Determine if differences in the incidence of latent infection of immature fruit relate to differences in susceptibility. 3) Survey pistachio germplasm collection for Panicle blight. Repeat surveys of pistachio collection (USDA-ARS, National Clonal Germplasm Repository, Davis, CA). FOR ALMOND: 1) Identify almond cultivars with resistance to Band canker. Repeat inoculations on mature trees of Nonpareil, Carmel, Padre, and Butte. Measure xylem vessel diameter and lignin content (see #1 for grape). 2) Evaluate putative causal agents of Lower limb dieback. Determine if the root pathogen Ilyonectria liriodendri predisposes branches to subsequent attack by canker pathogens Phomopsis amygdali and Neofusicoccum nonquaesitum. Co-inoculate roots of bare-rooted almond trees (cultivar Padre) with spore suspensions of I. liriodendri, pot these trees, and follow with woody-stem inoculations by P. amygdali and N. nonquaesitum. Then compare stem lesions of these trees with lesions in trees with either root or stem inoculation only. Goal 3. Develop and deploy new extension tools that increase adoption of preventative practices in young orchards and vineyards Our 2014 grower survey established a baseline on usage of three preventative practices for management of trunk diseases: delayed pruning, pruning-wound protectants, and double pruning. Rates of adoption in young vineyards were relatively low in all regions. Therefore, in 2014-2015 we will conduct socioeconomic behavioral experiments to examine the ways in which growers attend to and incorporate different types of social information into decision-making, as well as the influences of perceptions of future disease risk and risk-aversion to adoption of preventative practices. Simulated economic experiments will evaluate market-level effects from adoption, as well as district and market-level effects of adopting new detection tools and disease-resistant cultivars.

Impacts
What was accomplished under these goals? Goal 1. Develop new detection tools for diagnosticians, growers, and nurseries. There are effective practices to prevent wood-canker diseases of grape (aka trunk diseases), but because wood symptoms are internal and canopy symptoms do not appear for 1+ years, trunk diseases often go unnoticed. We completed first steps toward development of two new detection tools for the nursery and vineyard: 1) A molecular signature for the early stage of Botryosphaeria dieback. To detect the early stage (before shoots die back), we tested leaves for grapevine genes expressed within 1.5 months of Neofusicoccum parvum infection. Focus on N. parvum, and not other trunk pathogens, is due to the fact that it attacks all three hosts and ease of manipulation in the greenhouse/lab. Furthermore, testing leaves, tissues not infected by the pathogen, is a relatively new approach for detection of wood-infecting pathogens. Therefore, ‘proof of concept’ required a simplified design. Using RNA-Seq, we identified 12 genes induced by infection, but not by wounding alone. Screening 21 grape expression datasets confirmed the four best candidate genes (galactinol synthase, abscisic acid-induced wheat plasma membrane polypeptide-19 ortholog, embryonic cell protein 63, BURP domain-containing protein) were not affected by a range of widespread grapevine pathogens (e.g., Powdery mildew) or abiotic stresses (e.g., UV light) evaluated in past studies, and thus may serve as host-based markers of infection. 2) Spore traps for trunk pathogens in young vineyards. Detection of trunk pathogens via spore traps may alert growers of the need for preventative practices in young vineyards, which are too immature to show symptoms of trunk diseases. We compared the Rotorod trap (used commercially for detection of grapevine powdery mildew) to microscope slides coated in vaseline (study tool used by pathologists). We compared DNA-based detection from trap catches, using new molecular markers for three widespread pathogens (N. parvum, Eutypa lata, Phaeomoniella chlamydospora), to culture-based recovery. Spore traps were set in three young (3-5 years-old, vines asymptomatic) and three mature (13-15 years-old, vines symptomatic) vineyards each in Napa and San Joaquin Counties of northern California, December 2013-March 2014, and were retrieved within 24 hours of rain. With only eight rain events, comparisons of vineyard age, trap type, and detection method were difficult. Culture-based recovery from slides detected E. lata from 11 of 12 sites, N. parvum from nine sites, and P. chlamydospora from no sites. DNA-based detection from slides revealed E. lata from no sites, N. parvum from nine sites, and P. chlamydospora from two Napa sites. Rotorod traps yielded fewer pathogens in culture than slides, but had the same predominant species (E. lata, N. parvum). No PCR products resulted from Rotorod traps, possibly due to inhibition from soil particles that stick to the rods. To minimize inhibitors in 2014-2015, we will use Rotorod traps that spin automatically only with rain. Goal 2. Identify disease-resistant cultivars and germplasm accessions We evaluated resistance of grape cultivars to the following trunk diseases: 1) Phomopsis dieback. By comparing the genomes of progeny from a cross of Vitis vinifera ‘Chardonnay’ 95 x V. cinerea ‘B9’ that segregate for resistance to Phomopsis cane and leaf spot (fruit/foliar disease caused by the Phomopsis dieback pathogen Phomopsis viticola), Dr. Bruce Reisch (Cornell University, Geneva, NY; SCRI-funded Vitisgen project) identified grape genes associated with resistance. To determine if such genes also confer resistance to Phomopsis dieback, we inoculated woody stems of 10 resistant and susceptible progeny (and both parents, which are both resistant) to compare development of wood cankers, a symptom of Phomopsis dieback. Such genes could serve as markers. With several public and private table-grape breeding programs worldwide, Phomopsis markers would advance development of resistant table-grape cultivars, which are more susceptible than winegrapes to Phomopsis dieback. 2) Botryosphaeria dieback. Wine-grape cultivars show a range of resistance to Botryosphaeria dieback, but little is known about table-grape cultivars, other than high susceptibility of Thompson seedless. We are evaluating resistance of table-grape cultivars (Black Monukka, Fiesta, Flame seedless, Princess, Thompson seedless) to Botryosphaeria dieback pathogens N. parvum and Lasiodiplodia theobromae. Goal 3. Develop and deploy new extension tools that increase adoption of preventative practices in young orchards and vineyards The labor shortage, unclear management guidelines, and improper timing all contribute to growers not adopting preventative practices. Our goal is to encourage early adoption in young orchards and vineyards, before the diseases become established. Our survey of grape-growers made it clear that preventative practices are generally not adopted until 8+ years. To help reverse this trend, we developed the following new extension tools: 1) Guide to Vineyard Trunk Diseases in California. This pamphlet (printed in English and Spanish) is a concise, pictorial guide primarily for field crews, who are the first ‘line of defense’ in recognizing disease problems, but are nonetheless rarely the target of extension tools. Viticulture farm advisors who co-authored this pamphlet recognize that most information on trunk diseases focuses on differences among the pathogens, rather than the simple fact that the preventative practices are identical. This pamphlet is distributed to growers by extension agents. 2) treeandvinetrunkdiseases.org Project website features research updates. One way we advertise the site is to use it for presentations. This forces us to update contents and growers become familiar with our website as a source of new information on detection and management of trunk diseases. 3) Research briefs on the economic benefits of early adoption. Annual labor/material costs for preventative practices are easy for growers to compare on paper, but the benefits of these practices are not seen for many years. As such, the typical ‘trial-and-error’ that influences decision making for many vineyard practices do not apply to trunk disease management. We need to build a convincing case from the start. Research briefs (http://environmentalpolicy.ucdavis.edu/project/adoption-preventative-plant-disease-management-practices) feature vineyard costs/returns for five California regions. In 2014-2015, analyses will focus on Washington and Virginia.

Publications

  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Block KL, Rolshausen P, Cantu D. 2013. In search of solutions to grapevine trunk diseases through crowd-sourced science. Frontiers in Plant Science. 4: 394
  • Type: Journal Articles Status: Under Review Year Published: 2014 Citation: Bruez E, Baumgartner K, Bastien S, Travadon R, Guerin-Dubrana L, Rey P. In review. Pathogenic fungi and mycoparasites colonizing the functional woody tissues of asymptomatic grapevines with the trunk disease Esca. Phytopathology.
  • Type: Journal Articles Status: Under Review Year Published: 2014 Citation: Czemmel S, Galarneau ER, Travadon R, McElrone AJ, Cramer GR, Baumgartner K. In review. Grapevine genes expressed in asymptomatic leaves reveal the early stage of infection by the wood-infecting fungus Neofusicoccum parvum. Molecular Plant Pathology.
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Pouzoulet J, Pivovaroff AL, Santiago LS, Rolshausen PE. 2014. Can vessel dimension explain tolerance toward fungal vascular wilt diseases in woody plants? Lessons from Dutch elm disease and esca disease in grapevine. Frontiers in Plant Science 5:253.
  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Rolshausen PE, Akg�l DS, Perez R, Eskalen A, Gispert C. 2013. First report of wood canker caused by Neoscytalidium dimidiatum on grapevine in California. Plant Disease 97: 1511.
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Rolshausen PE, Baumgartner K, Travadon R, Fujiyoshi PT, Pouzoulet P, and Wilcox WF. 2014. Identification of Eutypa species causing Eutypa dieback of grapevine in eastern North America. Plant Disease 98: 483-491.
  • Type: Journal Articles Status: Awaiting Publication Year Published: 2014 Citation: Travadon R, Baumgartner K. In press. Molecular polymorphism and phenotypic diversity in the generalist, wood decay fungus Eutypa lata. Phytopathology.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2014 Citation: Baumgartner K, Travadon R, Hillis AV, Kaplan J, Cooper M, Lubell M. 2014. Grower perceptions of preventative practices for management of trunk diseases of grape. American Phytopathological Society Annual Meeting. Minneapolis, MN. 8/14/14
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2014 Citation: Baumgartner K, Travadon R, Lubell M, Hillis V, Kaplan J, Cooper M. 2014. Making the case for early adoption of preventative practices for management of grapevine trunk diseases. American Society for Enology and Viticulture Annual Meeting. Austin, TX. 8/14/14
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2014 Citation: Baumgartner K. 2014. Biology of fungal canker diseases of grape: prevention and management. Grape Pruning Workshop, Vineyard Team. Kendall-Jackson Vineyards, Soledad, CA 1/14/14 and Pacific Vineyard Company, San Luis Obispo, CA 1/15/14 (http://www.vineyardteam.org/virtual-tailgates/pruning-diseases/)
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2013 Citation: Baumgartner K. 2013. Diagnosis and control of trunk pathogens of grape. Pesticide Applicators Professional Association. Petaluma, CA. 11/7/13
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2014 Citation: Baumgartner K. 2014. Early adoption of preventative practices for management of trunk diseases. Tree and Vine IPM Breakfast Meeting. University of California Cooperative Extension, Stanislaus & San Joaquin Counties, Modesto, CA, 5/21/14
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2014 Citation: Baumgartner K. 2014. Early detection of trunk diseases. National Grape and Wine Initiative, Napa, CA, 7/28/14
  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Chen SF, Morgan DP, Michailides TJ. 2013. First report of Phoma fungicola associated with stem canker and fruit blight of pistachio. J of Plant Pathology 95:451.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2014 Citation: Michailides TJ, Chen, SF, Morgan DP, Puckett R. 2014. Etiology and management of diseases caused by Botryosphaeriaceae fungi on almond, pistachio, and walnut in California. P. 212 in Acta Phytopathologica Sinica, 10th International Congress of Plant Pathology. Aug 25-30, 2013. Beijing, China.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2013 Citation: Michailides TJ. Nut Crop Pathology: Bacterial spot, Botryosphaeria, and AF36. Sixth Annual Nut Crop Conference. November 13, 2013. Modesto, CA
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2014 Citation: Michailides TJ. Pistachio and walnut diseases and control. 2014 Bayer Crop Science Winter Symposium. February 15, 2014
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2014 Citation: Michailides TJ. Identification and Management of common pistachio disease. American Pistachio Industry 2014 Conference. February 19, 2014. San Diego, CA
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2013 Citation: Baumgartner K. 2013. Early detection of trunk pathogens in the vineyard. Trunk Disease Management Symposium. Lodi Winegrape Commission, Lodi, CA. 11/5/13
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2014 Citation: Baumgartner K. 2014. Management of trunk diseases by preventative vs. post-infection means. Treasury Wine Estates Limited, Calistoga, CA, 1/27/14
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Chen SF, Morgan DP, Michailides TJ. 2014. Botryosphaeriaceae and Diaporthaceae associated with panicle and shoot blight of pistachio in California, USA., Fungal Diversity DOI 101007/s13225-014-285-6.


Progress 09/01/12 to 08/31/13

Outputs
Target Audience: The target audience consists primarily of almond, grape, and pistachio growers, and secondarily of consultants associated with the production of these crops (e.g., pest control advisors, diagnosticians). Communication with the target audience is facilitated by national, state, and regional grower organizations and by cooperative extension agents. Examples of specific grower organizations include the National Grape and Wine Initiative, Almond Board of California, California Pistachio Research Board, California Table Grape Commission, Association for Applied IPM Ecologists, California Association of Pest Control Advisors, and the Lodi Winegrape Commission. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Our communities of interest are almond, pistachio, and grape growers, pest control advisors (PCAs) who make recommendations to these growers on how to manage wood-canker diseases, and diagnosticians tasked with detection of wood-canker pathogens from field samples. Our progress toward achieving the goals of this SCRI project (development of detection tools, identification of disease-resistant cultivars, encouraging adoption of preventative practices) hinges on an open line of communication with our communities of interest. Preliminary reporting of research results to our stakeholders and regular feedback on our progress gives us the opportunity to fine-tune our studies and, ultimately, to have the greatest impact on crop production. We have the traditional means of disseminating results (conference presentations, workshops with growers, journal publications), as evidenced by our 30+ product entries for this reporting period. The less traditional means (social media, video-archived demonstrations, publically-available genome sequences, searchable DNA-sequence databases) are also a main focus of our research team. This latter category provides more of an opportunity for dialogue with our communities of interest. To meet the goal of encouraging our communities of interest to adopt preventative practices in young orchards and vineyards, we established a Survey Advisory Board, developed a series of surveys, and created new extension tools. Almost every step toward reaching this goal gives us the opportunity to interact with our communities of interest. The strong foundation for such interactions is the Survey Advisory Board, which consists of agricultural associations and extension agents. These partnerships made for a very focused set of survey questions, efficient distribution of the surveys, and regular channels of communication for new extension tools. Our first survey, an online survey for PCAs, was distributed via email by the California Association of PCAs to 1,380 members. Our second survey, an interactive Turning Point survey for growers, was conducted at six meetings (287 growers total) organized by members of our Survey Advisory Board. To keep the attention of our communities of interest, preliminary results were reported to survey participants within approximately one week via email or social media (e.g., www.lodigrowers.com/trunk-disease-survey-results-part-iii-of-iii/). What do you plan to do during the next reporting period to accomplish the goals? Goal 1. Develop new detection tools for diagnosticians, growers, and nurseries. · Determine specificity of early detection tool. Wood-canker pathogens disrupt the flow of water/nutrients in almond, pistachio, and grape. As such, we expect a ‘molecular signature’ of infection in plant leaves may signal both the presence of a wood-canker pathogen and plant genes associated with water/nutrient stress. Other fungal pathogens (esp. pathogens on the leaves, which are the tissues we sample) also may trigger a similar molecular signature. To verify the specific molecular signature, we will subject plants to a combination of infection and water/nutrient stress or infection by foliar pathogens. In this way, we can identify non-specific genes and develop an accurate early detection tool that does not have a high rate of false positives. · Develop a web-based detection tool for identification of wood-canker pathogens. The community of interest for this detection tool is disease diagnosticians. Disease diagnosis is more than just accurate identification of a pathogen. Diagnosticians must also communicate to the grower the proper level of concern – Is it an urgent wood-canker disease problem or a false alarm? This database utilizes a DNA ‘barcode’ (specifically, the Internal Transcribed Spacer region) for accurate molecular identification of putative pathogens. Equally important is the categorization of each fungus in the database as a known wood-canker pathogen, a suspected (and untested) wood-canker pathogen, or a known non-pathogenic fungus. · Develop field detection tool. The spores of wood-canker pathogens are spread by wind or rain, depending on the species. One of the detection tools we are developing is trapping spores from vineyards during the dormant season, and then using a laboratory assay to test the trap catch for the DNA of the spores. The utility of this detection tool will be to inform the annual timing of preventative practices (i.e., when to prune). It will also help evaluate disease risk in young vineyards (i.e., year to start using preventative practices). Also, it may justify the expense of preventative practices, given that their efficacy cannot be evaluated within a growing season. Goal 2. Identify disease-resistant cultivars and germplasm accessions · Field surveys of germplasm collections of pistachio, almond and grapevines to identify promising plant material for rapid phenotyping assays. Resistant pistachio and almond cultivars, identified from lathouse experiments, will be evaluated under field conditions. Additional characterization of grape resistance to Eutypa dieback will be performed in greenhouse assays. We will compare the expression profiles of grape genes potentially involved in disease resistance between resistant and susceptible cultivars, which were identified from our rapid screening assays. Knowledge of the genetics of trunk disease resistance in grapevine will open opportunities for breeding programs. Anatomical and biochemical markers of resistance in plant cell walls will be characterized in the almond and pistachio cultivars that were phenotyped in the first year. Correlations between phenotyping assays, and anatomical and biochemical data will strengthen our findings. Goal 3. Develop and deploy new extension tools that increase adoption of preventative practices in young orchards and vineyards · Develop smart phone and web-based applications for diagnosis of wood-canker diseases. Growers will be guided through an identification key, which will lead to diagnosis of specific wood-canker diseases. Also, they can submit samples to nearby diagnostic labs. Currently, we are developing flow-charts for each disease (i.e., each step of the identification key), and setting up the platform for application development and database development. Our aim is to develop a beta-version by May 2014. ·Publish a pamphlet on diagnosis of trunk diseases of grape in CA. This is a concise, printed pamphlet for diagnosis and management. Photographs show diagnostic symptoms for each trunk disease, with instructions on when to look for symptoms. This is a collaborative effort between the Baumgartner USDA-Ag. Research Service lab, University of CA – Integrated Pest Management Program (Lucia Varela), and University of CA Cooperative Extension farm advisors Monica Cooper (Napa County), Rhonda Smith (Sonoma Counry), and Larry Bettiga (Monterey, San Benito, and Santa Cruz Counties).

Impacts
What was accomplished under these goals? Goal 1. Develop new detection tools for diagnosticians, growers, and nurseries. There are effective practices to prevent wood-canker diseases of grape (aka trunk diseases), but because the wood canker is internal and the leaf symptoms do not appear for several years, growers do not know a vineyard is infected until it is too late. Our goal is to develop detection tools that reveal wood-canker pathogens in the nursery and vineyard. One problem with current detection tools, which require sampling the wood infected by the pathogen, is the lengthy processing time in the diagnostic lab. An early detection tool under development in the Baumgartner and Cramer labs will sample healthy-looking leaves for grape genes that are unique to the early stage of infection – the molecular signature – before symptoms appear. Testing leaves, a tissue not directly infected by the pathogen, is a relatively new and unproven approach for plant disease detection, but is worth pursuit because it promises to reduce per-sample costs and thus make trunk disease detection affordable. Our first experiment is on the model wood-canker pathogen Neofusicoccum parvum. We identified the timing of the early stage of infection (i.e., before the pathogen spreads beyond the infection site and symptoms appear) at under 2 months, and are currently identifying the molecular signature in grape leaves at this time point. This early detection tool will minimize disease spread from the nursery and will increase the number of years of vineyard profitability in the long run by allowing for quick detection and removal of infected plants. A second detection tool that tests for the spores of wood-canker pathogens – a spore trap – is also under development in the Baumgartner, Michailides, and Rolshausen labs. Vineyards become infected by the microscopic propagules – spores – of trunk pathogens when they are spread by wind or rain. The Rotorod spore trap is in commercial use for detection of powdery mildew of grape in the growing season. Our experiment tests this spore trap for detection of trunk pathogens of grape in the dormant (rainy) season, which is when the spores of wood-canker pathogens are produced. To facilitate rapid pathogen detection from the trap catches in the diagnostic lab, we developed molecular markers specific to the spore DNA. Rotorod spore traps are in place from December 2013 to March 2014 in young and mature vineyards. If spores are detected in young vineyards, which are too immature to show symptoms of trunk diseases, then grape growers will be alerted to the need for preventative practices. Goal 2. Identify disease-resistant cultivars and germplasm accessions Newly-released pistachio cultivars were tested for resistance. We identified the most aggressive pathogens, which were then used for inoculations. ‘Lost Hills’ and ‘Golden Hills’ were most resistant. ‘Kalehghouchi’ was most susceptible and in fact was more so than ‘Kerman’ (98% of current pistachio acreage). New cultivars ‘Lost Hills’ and ‘Golden Hills’thus seem promising. Field surveys detected severe disease in ~50% of the CA almond acreage, which represents 55% of the Nation’s production. In autumn 2012, spore trapping in a diseased orchard revealed pathogen sporulation patterns, which will inform disease management guidelines. Differences in susceptibility to canker diseases caused by Botryosphaeriaceae species were found among commercial almond cultivars. In addition, up to eight different fungal species were isolated, and the two most virulent species were inoculated to 10 almond cultivars. Among these, ‘Carmel’, ‘Padre’, ‘Nonpareil’, and ‘Sonora’ were most susceptible, which matched field observations. In grape, current phenotyping assays are too time-consuming for breeding programs. We developed a rapid and reliable screening assay for resistance to Eutypa dieback, by comparing three assays: 1. potted grapes propagated from dormant cuttings (traditional method for comparison), 2. potted grapes mist-propagated from green cuttings, and 3. a detached-cane assay with dormant cuttings. The 3rd assay was rapid and reliable – evaluations were made after only 8 weeks, which is in contrast with the year-long 1st and 2nd assays. This rapid screening assay will provide opportunities for screening additional germplasm accessions, which have been identified from field surveys in the USDA National Clonal Germplasm Repository (Davis, CA) for two consecutive years. We examined structural and chemical changes in wood following infection, and identified anatomical or chemical markers of resistance to wood-canker diseases. In our first experiment, we inoculated four grape cultivars (‘Merlot’, ‘Cabernet-Sauvignon’, ‘Chardonnay’, ‘Thompson seedless’) with the four most widespread and aggressive trunk pathogens. Disease progress is being evaluated with microbiological techniques, and pathogen quantification with molecular techniques. Analysis of plant cell walls’ structural and chemical modification in response to infection showed differences that corresponded to susceptibility to these pathogens, with cultivar ‘Merlot’ being the most resistant. ‘Merlot’ has smaller xylem vessels and higher lignin content than susceptible cultivars, suggesting that these features play a role in disease resistance. Goal 3. Develop and deploy new extension tools that increase adoption of preventative practices in young orchards and vineyards The labor shortage, inaccurate disease management guidelines, and improper timing/ application are all part of the complex set of factors that can explain why growers do not adopt preventative practices for wood-canker diseases. Our goal is to encourage early and routine use of preventative practices in young orchards and vineyards, BEFORE wood-canker diseases become established. We report here the first baseline trends in usage of preventative practices. From a survey of California pest control advisors (PCAs), we found that prevention of wood-canker diseases of grape (aka trunk diseases) is not common practice in young vineyards, but that many growers instead resort to costly post-infection tactics (i.e., retraining or replanting) in mature vineyards made unprofitable due to years of not doing anything to manage wood-canker diseases. This is in spite of the fact that experimental trials show the following preventative practices are effective: delayed pruning, double pruning, and applications of pruning-wound protectants. In a new grower survey, our objective is to determine why these three preventative practices are not used on a routine basis in young vineyards. Our grower survey has been conducted in six meetings to date, using the audience-response software Turning Point. Preliminary results show that the majority of growers who use one of the preventative practices do so in vineyards averaging over 10-years old, which is AFTER disease symptoms appear in the vineyard. Our economic analyses of vineyard profitability over a 25-year lifespan show that adopting such practices in year 10 means that a vineyard will be profitable for only 12-15 years and is similar to NEVER adopting such practices. In contrast, adopting preventative practices in years 2 or 5 ensures 25 years of positive returns. With a clear understanding of trends in usage and grower perceptions, we are developing concise extension tools that focus on encouraging early and routine adoption of preventative practices.

Publications

  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Michailides TJ. Effect of Luna products in controlling Botryosphaeria spp. in pistachio. Bayer Innovation Conference in Monterey. Feb 2013.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Michailides TJ. Plant Pathology update on diseases caused by Botryosphaeriaceae. Pistachio Day Farm Advisor Training Tour and Workgroup Meeting. University of California Cooperative Extension. Coalinga, CA. July 11, 2013.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Michailides TJ. Botryosphaeria canker of almond and walnut. Nut Crop Meeting. Wilbur-Ellis. Modesto, CA. November 13, 2013.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Michailides TJ. Epidemiology and management of Botryosphaeria panicle blight and other disease of pistachio. Pistachio Growers Association., Inc. Berri, SW Australia, February 12, 2013.
  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Chen SF, Morgan D, Beede RH, Michailides TJ. 2013. First report of Lasiodiplodia theobromae associated with stem canker of almond in California. Plant Disease 97:994.
  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Chen SF, Morgan, DP, Michailides TJ. 2013. First report of Phoma fungicola associated with stem canker and fruit blight of pistachio in Arizona. Journal of Plant Pathology 95:451.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Michailides TJ, Morgan, DP, Puckett RD, Chen SF. Intimacy of Botryosphaeriaceae and temperate nut crops in California. American Phytopathological Society, Pacific Division Annual Meeting. Tucson, AZ, June 17, 2013.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Michailides TJ, Doll, DA. Bacterial spot, Botryosphaeria canker, and biocontrol of aflatoxins of Almond. Almond Board of California Annual Conference. Sacramento, CA. December 5, 2013.
  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Baumgartner K, Fujiyoshi PT, Travadon R, Castlebury LA, Wilcox WF, Rolshausen PE. 2013. Characterization of species of Diaporthe from wood cankers of grape in eastern North American vineyards. Plant Disease 97: 912-920.
  • Type: Websites Status: Published Year Published: 2013 Citation: Baumgartner K, Travadon R, Hillis V, Kaplan J, Lubell M. 2013. Trunk Disease Survey. Lodi Winegrape Commission, www.lodigrowers.com/trunk-disease-survey-results-part-iii-of-iii/ (posted 11/27/13)
  • Type: Websites Status: Published Year Published: 2013 Citation: Baumgartner K, Travadon R. 2013. Vineyard trunk diseases in California. UCCE Central Sierra, http://cecentralsierra.ucanr.edu/Agriculture/Viticulture/Grape_Pests_Diseases/Grape_vine_canker_disease/?editon=0 (posted 10/30/13)
  • Type: Websites Status: Published Year Published: 2013 Citation: Travadon R, Baumgartner K. 2013. Eutypa dieback in northern California vineyards. Lodi Winegrape Commission, http://www.lodigrowers.com/eutypa-dieback-in-northern-california-vineyards-part-ii-of-ii/ (posted 10/28/13)
  • Type: Websites Status: Published Year Published: 2013 Citation: Baumgartner K, Travadon R. 2013. Guide to managing vineyard trunk diseases in Lodi. Lodi Winegrape Commission, http://www.lodigrowers.com/guide-to-managing-vineyard-trunk-disease-in-lodi/ (posted 9/19/13)
  • Type: Journal Articles Status: Under Review Year Published: 2013 Citation: Travadon R, Baumgartner K. In review. Molecular polymorphism and phenotypic diversity in the generalist, wood decay fungus Eutypa lata. Journal of Evolutionary Biology.
  • Type: Journal Articles Status: Awaiting Publication Year Published: 2013 Citation: Rolshausen PE, Baumgartner K, Travadon R, Fujiyoshi P, Pouzoulet J, Wilcox WF. In press. Identification of Eutypa species causing Eutypa dieback of grapevine in eastern North America. Plant Disease.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Baumgartner K, Travadon R, Galarneau E, McElrone AJ. Defining the stages of infection of grapevine stems with the trunk disease Botryosphaeria dieback. American Phytopathological Society Annual Meeting. Austin, Texas. August 11, 2013.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Baumgartner K. Preventative practices for management of trunk diseases in the vineyard. Association of Applied IPM Ecologists. Grape PCA Roundtable. Tulare, CA. December 3, 2013.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Baumgartner K. New detection tools for trunk pathogens in the vineyard. Sonoma County Vineyard Technical Group, University of California Cooperative Extension. Santa Rosa, CA. November 21, 2013.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Baumgartner K. Diagnosis and control of trunk pathogens of grape. Pesticide Applicators Professional Association. Petaluma, CA. November 7, 2013.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Baumgartner K. New detection tools for trunk pathogens in the vineyard. Trunk Disease Management Symposium. Lodi Winegrape Commission, Lodi, CA. November 5, 2013.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Baumgartner K. Wood-canker diseases (a.k.a. trunk diseases) of grape. California Association of Pest Control Advisors, Modesto, CA. March 7, 2013.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Doll DA, Michailides TJ, Rolshausen PE. 2013. Botryosphaeriaceae associated with almond trunk cankers: a threat to the almond industry? Phytopathology 103: S3.12.
  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Travadon R, Rolshausen PE, Gubler WD, Cadle-Davidson L, Baumgartner K. 2013. Susceptibility of cultivated and wild Vitis to wood infection by fungal trunk pathogens. Plant Disease 97: 1529-1536.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: 29. Cantu D, Amrine KCH, Blanco-Ulate B, Jones L, Morales-Cruz A, Lawrence DP, Travadon R, Riaz S, Walker MA, Rolshausen PE, Baumgartner K. 2014. Genomics of Grapevine Diseases. International Plant and Animal Genome XXII Conference. San Diego, CA. January 12, 2014.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Doll DA. 2013. Botryosphaeria wood cankers in almonds. Northern San Joaquin Valley Almond Day. University of California Cooperative Extension. Modesto, CA. February 1, 2013.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Doll DA, Michailides TJ. 2013. OMRI approved fungicides for control of Botryosphaeria Pannicle Blight in Pistachio. Pistachio Research Day. California Pistachio Research Board. Parlier, CA. January 17, 2013.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Doll DA. 2013. Botryosphaeriaceae fungal pathogens infecting almond pruning wounds. San Joaquin Sustainable Farming Project Field Day. Sustainable Cotton Project. Firebaugh, CA. February 27, 2013.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Doll DA, Michailides TJ. 2013. Pruning wound cankers of almonds: What we know. UC Almond Field Tour. University of California Cooperative Extension. Ballico, CA. April 24, 2013.
  • Type: Websites Status: Published Year Published: 2013 Citation: Baumgartner K, Travadon R, Hillis V, Kaplan J, Lubell M. 2013. Preliminary Reports - Trends in Preventative Trunk-Disease Management and Grower Perceptions of Practice Efficacy in California Crush Districts 1, 2, 3, 4, 10, and 12. http://environmentalpolicy.ucdavis.edu/project/adoption-preventative-plant-disease-management-practices
  • Type: Journal Articles Status: Under Review Year Published: 2013 Citation: Pouzoulet J, Pivovaroff AL, Santiago LS, Rolshausen PE. In review. Can xylem resistance to drought stress explain tolerance to fungal vascular wilt diseases? Lessons from Vitis vinifera. Frontiers.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Gispert C, Rolshausen PE, Vasquez S. Canker Diseases in the Coachella Valley: Incidence and Evaluation of Management Strategies. American Society for Enology and Viticulture Annual Meeting. Monterey, CA. June 24-28, 2013.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Rolshausen PE. Wood disease management options for grapevines in the San Joaquin Valley. Grape Day. University of California Kearney Agricultural Research and Extension Center, August 13, 2013.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Rolshausen PE. Controlling trunk diseases. Annual Viticulture Research Road Show. San Joaquin Valley Winegrowers Association. Fresno, CA. June 13, 2013.
  • Type: Journal Articles Status: Under Review Year Published: 2013 Citation: Chen SF, Morgan D, Michailides TJ. In review. Botryosphaeriaceae and Diaporthaceae associated with panicle and shoot blight of pistachio in California, USA. Fungal Diversity.