Grant Information

PLANT DISEASE EPIDEMIOLOGY AND SYSTEM SUSTAINABILITY

Sponsoring Institution National Institute of Food and Agriculture
Status COMPLETE
Funding Source HATCH
Division NIFA Formula
Reporting Frequency Annual
Project Director McRoberts, Neil
Accession Number 226674
Project Number CA-D-PPA-2131-H
Dates 2011-10-01 - 2016-09-30
Performing Department Plant Pathology
Recipient Organization UNIVERSITY OF CALIFORNIA, DAVIS
410 MRAK HALL
DAVIS,CA 95616-8671
Keywords plant disease epidemiology
policy
resilience
sustainability
systems dynamics
Research Effort Applied (0%)
Basic (0%)
Developmental (0%)
Classification Parameters
Knowledge AreaSubject of InvestigationField of SciencePercent
212 - Pathogens and Nematodes Affecting Plants 2410 - Cross-commodity research--multiple crops 1170 - Epidemiology 50%
609 - Economic Theory and Methods 6199 - Economy, general/other 3010 - Economics 50%
Non-technical Summary

This research is intended to develop an analytical toolkit that will allow the effects of plant disease on the sustainability of agricultural or natural systems to be studied in a formal way. Plant diseases are a major constraint on food production, a cause of uncertainty in food security, and a threat to valuable goods and services in natural habitats. Despite these important consequences for sustainability, there has been no concerted effort to study how or to what extent plant disease directly affects sustainability. The project will address this gap using a combination of case studies and statistical and theoretical modeling. The work examines how plant disease and epidemiology can be linked and how the occurrence of disease impacts on indicators in the three main domains of sustainability: environmental, economic and societal. In addition to the scientific results which the project will generate, since it deals with subjects of high priority in several policy areas and of relevance to strategic decision-making, one of the key objectives is to develop and publish non-technical summaries of all the major scientific results, for use by non-scientific audiences.

Goals / Objectives

The goal of this research is to develop a formal framework to link measureable attributes of plant disease epidemics to the sustainability of agricultural and natural systems at a number of spatial, temporal and organizational scales. The work will draw on case studies of plant disease epidemics of current concern in California and existing systems theory to achieve this goal. The objectives are to

  1. determine the generic properties of plant disease epidemics that can be linked to sustainability
  2. develop a formal definition of system sustainability which can be linked to the properties determined in (1)
  3. use simulation modeling to study the sensitivity of sustainability to epidemic properties
  4. develop a declarative model, or set of models, which summarize the results obtained in objectives (1) to (3)
  5. examine the implications of the theoretical results obtained in objectives (1) to (3) for one or more of the case studies under empirical investigation in the PI's laboratory
  6. examine the consequences of the theoretical studies for policy-driven or outreach activities designed to impact on sustainability through affects on farmer behavior, using cause-effect modeling

The expected outputs are: (1) peer-reviewed papers summarizing the results obtained in the various objectives; (2) simplified briefing papers suitable for policy or extension audiences summarizing the main implications of the research; (3) dedicated webpages on the PI's lab website providing summaries of both types of output; (4) presentations at scientific meetings and for audiences of other types of stakeholder in the research.

Methods (unparsed)

The research will employ a variety of analytical techniques including: statistical data modeling; formal mathematical modeling; numerical simulation. Statistical modeling will be used to extract epidemiological parameters from data sets collected on the case studies. These properties will be captured in algebraic (i.e. mathematical models) describing the generic epidemiological properties which the statistical parameters estimate. The algebraic models will be studied for their analytical properties (e.g. entailed asymptotic behavior) and, where necessary numerical simulation will be used to examine the temporal dynamics of the models.

Methods
The research will employ a variety of analytical techniques including: statistical data modeling; formal mathematical modeling; numerical simulation. Statistical modeling will be used to extract epidemiological parameters from data sets collected on the case studies. These properties will be captured in algebraic (i.e. mathematical models) describing the generic epidemiological properties which the statistical parameters estimate. The algebraic models will be studied for their analytical properties (e.g. entailed asymptotic behavior) and, where necessary numerical simulation will be used to examine the temporal dynamics of the models.
Project Timeline Tracking

Outputs

Target Audience
Audiences reached fall into two main groups: scientists and other stakeholders. The main groups of scientists reached are those directly working on the key plant diseases that we have studied, principally Huanglongbing (HLB) in citrus, red leaf viruses in grapes and downy mildew in spinach. Over the course of the project we have published refereed papers and attended state, national and international scientific meetings at which our work on the impacts of plant disease on sustainability has been presented. Highlights among the outreach to scientists include keynote papers at conferences in New Zealand in 2014 and 2015 at the International Research Conference on HLB in 2015 and 2017, and at the Brazilian Phytopathology Society annual meeting in 2016. Outreach to non-scientist target audiences focused on state and national regulatory officials (California Department of Food and Agriculture and USDA-APHIS), grower-organizations (marketing order groups such as Citrus Research Board, American Vineyard Foundation, CA Grape Rootstock Improvement Commission, CA Leafy Greens Research Board, CA Tomato Research Institute), and growers. The project has an active program of outreach associated with it, particularly in grape and citrus, but also quite strong in leafy greens and processing tomato. Over the lifetime of the project we conducted between one and two direct outreach events per month, some being large-audience grower meetings, others being committee work and focused interactions on specific topics involving only one to a few stakeholders. Regular activities under this heading include annual presentations at the California Current Viticulture Research Meeting, the CA Leafy Greens Research Board annual meeting, and the Citrus Research Board annual review. In addition we worked closely with CDFA to re-write the sampling protocols for the grape certification program and provide special scientific advice the Citrus Research Board on epidemiology of HLB.

Changes / Problems
Nothing Reported

Training & Professional Development
Two post-doctoral researchers were trained in analytical methodology related to the project. The post-docs learned different sets of methods appropriate to the specific problems on which they were working, but both have much increased analytical ability having passed through the program. One graduate student was trained in/contributed to the development of methods for studying disease inoculum dynamics in the context of a system where inoculum moves freely between different locations and the ability of individual growers to prevent disease on their own is limited. The graduate student secured a post-doc position at the University of Florida after completing his PhD where he will be able to apply the analytical skills developed in Davis. A second graduate student was mentored jointly by Prof Lubell (Center for Environmental Policy & Behavior, UC Davis) and was trained in the elicitation and analysis of cognitive models of sustainability. The student secured a position in health-care data analysis and as a statistical consultant for a US data analysis and consultancy corporation.

Dissemination Streams
Research findings from the project have been published in refereed papers and presented at national and international scientific meetings. Members of the project team regularly participate in industry outreach meetings in California where their work on specific crop systems is delivered directly to growers and pest control advisers. The project PI serves on several state committees and advisory boards allowing expertise to be transfered directly to decision-makers.

Next Reporting Steps
Nothing Reported


Publications Inventory

Journal Articles

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Conference Papers and Presentations