The devastating symptoms of a disease of citrus had been recorded in the late 19th century in China. These symptoms were usually attributed to nutritional problems. The disease was further reported in various parts of Asia and Africa. In the 1950s, the Chinese researcher K. H. Lin showed the disease to be the result of a transmissible agent. However, all of these observations and research results were virtually unnoticed by researchers in the West at the time of their publication. The disease is commonly referred to in the United States as “citrus greening”. Citrus greening is also known as huanglongbing or HLB; huanglongbing is translated from Chinese as “yellow shoot disease”. HLB became generally recognized as a threat to the citrus industry in the 1960s and 1970s, the period in which a bacterial etiology for the disease was suggested from electron microscopy studies and its transmission by a small insect, any of several species of psyllids, was documented. One of these psyllids, the Asian citrus psyllid (ACP), was discovered in Florida in 1998, and in 2005 symptoms of HLB were observed by scouts in urban plantings in southeastern Florida. Both the ACP and HLB rapidly spread into the commercial citrus growing areas of Florida.
Florida citrus is recognized as an industry that has been assaulted by hurricanes and freezes, numerous diseases and pests, shortages of water, and urban encroachment. In this panoply of threats, citrus greening is recognized as the greatest threat, a threat to the very survival of the industry.
In early 2008, the Florida Department of Citrus (FDOC) requested the assistance of the National Academy of Sciences (NAS) in addressing the citrus greening problem in Florida. The NAS was asked to convene a panel of experts, with the charge of identifying research priorities for citrus greening (HLB) and creating a request for research proposals (RFP) based on the identified research priorities. The NAS was also requested to review and evaluate, for scientific and technical merit and feasibility, the proposals that would be submitted in response to the RFP. The panel of experts met in April of 2008 and identified research priorities. The National
Research Council (NRC) of the NAS developed a list of eight subject areas under which research proposals on HLB could be considered and identified potential review panel members for each. The review panels were appointed, and during the fall of 2008 the review panels met in Washington, D.C., each panel evaluating the corresponding set of proposals. Subsequently, a new panel composed of the chairs of the individual panels and the chair of the new panel, who had not participated in the initial process, evaluated all of the proposals. In December of 2008, the new panel submitted a list of research proposals that were deemed worthy of funding for consideration by the FDOC, which had allocated $20 million for research on citrus HLB and other serious citrus diseases.
PURPOSE AND SCOPE OF THE STUDY AND THE FORMATION OF THE COMMITTEE
As part of its request for assistance with the citrus HLB problem, the FDOC also asked the NAS to assemble and support a study committee that was assigned the task of developing a strategic plan for dealing with the citrus HLB problem. The strategic plan is to deal with the near-term mitigation and research efforts and, in the longer term, organizational and technical approaches to reducing the damaging effects of this devastating disease. The formal proposal to develop the strategic plan was approved by the Executive Committee of the NRC’s Governing Board on March 12, 2008. However, the Statement of Task was subsequently revised to include recommendations for ways that the Florida citrus industry can improve its capacity to respond to citrus HLB in a more comprehensive way. The revised Statement of Task, as approved in March, 2009, may be found as Appendix A of this report. In April of 2009, the NRC formed the Committee on Strategic Planning for the Florida Citrus Industry: Addressing Citrus Greening Disease (Huanglongbing). Biographical information on the committee members is presented in Appendix B. Given the urgency of the citrus HLB situation in Florida, the study was placed on a fast-track schedule for completion in early 2010 rather than allowing the usual 18 months or more for completion of a NRC committee report.
CHARGE TO THE COMMITTEE
The Committee was asked to examine the following:
The current citrus disease situation in Florida and the status of public and private efforts to address citrus greening and other diseases; including lessons learned
The capacity of the industry to mobilize a scientifically-based response to current disease threats and to translate scientific advances into products and services for the protection of Florida citrus industry in the short and long term
The relationship of the industry to public, academic, and private research, and to regulatory and funding organizations at the state and federal level, with respect to controlling citrus greening and developing a comprehensive solution to citrus greening and other diseases.
COMMITTEE’S APPROACH TO THE STUDY
Part of the challenge to producing this report was the relatively short period given to the committee to complete its task. This was due to the urgency of finding ways to manage citrus greening before it becomes economically infeasible to produce citrus in Florida. The study began with a consultation with representatives from the Florida citrus industry, representatives from federal and state agencies, and the university research community, most of whom formed the study’s liaison committee (Appendix C). The purpose was to get first-hand information on 1) the impacts of citrus greening and the actions taken by citrus growers and 2) the ongoing regulatory and research activities to address citrus HLB.
As part of the information-gathering phase, the committee also asked experts from different scientific and technological fields to submit a short written report on a topic selected by the committee. Based on the submitted reports, the committee selected a subset from the group to meet with the committee in person or by telephone to discuss new research findings, promising results, and technologies with potential application to the mitigation of HLB. Presentations were given at the open session of the second Committee meeting in Washington, D.C. The committee met a total of three times, once in Florida (May, 2009) and twice in Washington, D.C. (July and September, 2009). Except for testimony collected from the selected experts, the meetings were in closed session. A list of all oral presentations and speakers and sources of written statements are given in Appendix D.
All of the members of the review panels, the strategic planning committee, and the liaison committee were selected by the NRC. As indicated above, other experts who provided input were selected by the committee. None of the people who served on the panels or committees or provided testimony were remunerated for their service.
ORGANIZATION OF THE REPORT
This report, the result of a fast-track study, is composed of 5 chapters and 13 appendixes. Chapter 2 provides a historical review of the citrus industry, citrus diseases and other constraints on citrus production, and details on HLB, including the discovery of its infectious nature, likely causal agent and insect vector and current methods for mitigating the disease. Some gaps in research efforts are also indicated. Also examined in Chapter 2 are the roles of, and relationships between, federal, state, university, and industry organizations with connections to citrus production and processing. The focus of Chapter 3 is on research results related to HLB and their possible applications in HLB mitigation. Prior to the invasion of HLB into Florida, published research results on the bacterium and insect vector were few. Subsequently, there has been a dramatic increase in publications on these topics. Chapter 4 presents the specific recommendations of the Committee as they relate to organizational changes, informational initiatives, and research and technology projects with near-term, near- to intermediate-term, and long-term potential. An analysis of the factors supporting and not supporting the recommendation is presented with each recommendation. Chapter 5 contains the Committee’s recommendations for implementation of recommendations and a comparison of various models for supporting and managing research. Preparing for the future of the Florida citrus industry is also a topic of Chapter 5.