Xylella fastidiosa is a bacterial pathogen that infects a broad range of plant species. The species is best known as the causative agent of Pierce's disease of grape and citrus variegated necrosis, although other recent epidemics affecting high value food crops such as olives, coffee, has substantially increased general public awareness of the agricultural impact imposed by this pathogen. In the northeastern United States, Xylella fastidiosa presents a major disease problem as the causative agent of bacterial leaf scorch (BLS) of oak. BLS of oak is currently the only reported disease caused by X. fastidiosa in the northeasternUSregion. Three major concerns of BLS of oak are: 1) the significant threat the disease poses to ancient oak stands throughout the eastern United States; 2) the threat of pathogen spread within the region to other plant hosts, including other hardwood and shade tree species, and economically relevant agronomic crops; and 3) the lack of viable methods to control the disease and its spread.While BLS of oak has been observed in the region over the past four decades, little is known about the disease or the causative agent. This lack of knowledge is due largely to difficulties or working with the pathogen and host plant under experimentally controlled conditions, and thus the inablity to detect and monitor pathogen populations.In our previous work, we developed a molecular genetic approach to detect and characterize pathogen populations directly from plant tissue. Molecular detection of pathogens was specific; individual pathogen populations were distinguishable over geographical regions, as well as between trees. In this study, we intend to utilize our molecular approach to expand knowledge of how the disease spreads by tracking specific pathogen populations between oak trees. We will also monitor non-oak plant species in the region for their potential to harbor the pathogen, regardless of whether the plants display scorch symptoms. We intend to also expand our method to detect and characterizepathogen populations in insects suspected of transmitted the disease between plants. Results obtained from this study will be analyzed to gain a better understanding of disease epidemiology for the purpose of re-assessing current practical disease management options, as well as developing new management options to control disease spread.This study is expected to answer the following questions:1) What critical factors contribute to disease spread among oak?2) Why hasn't disease noticeably spread to other known plants species grown in the northeastern United States?3) What is the potential for disease to other plants spread in the future? And,4) Are there better practical management options to control disease?
|Effective start/end date||12/7/15 → 10/31/20|
- National Institute of Food and Agriculture (National Institute of Food and Agriculture (NIFA))