Grant Information
| Knowledge Area | Subject of Investigation | Field of Science | Percent |
|---|---|---|---|
| 123 - Management and Sustainability of Forest Resources | 621 - Broadleaf forests of the South | 1160 - Pathology | 25% |
| 124 - Urban Forestry | 2110 - Ornamental trees and shrubs | 1160 - Pathology | 20% |
| 216 - Integrated Pest Management Systems | 621 - Broadleaf forests of the South | 1160 - Pathology | 20% |
| 216 - Integrated Pest Management Systems | 2110 - Ornamental trees and shrubs | 1160 - Pathology | 15% |
| 123 - Management and Sustainability of Forest Resources | 2110 - Ornamental trees and shrubs | 1160 - Pathology | 10% |
| 124 - Urban Forestry | 621 - Broadleaf forests of the South | 1160 - Pathology | 10% |
Trees make a huge impact on the quality of life and economy in Texas through their historical and aesthetic attributes, contributions to property values, ecosystem services, and timber values. A wide variety of forest types and woodlands occurs in Texas. There are therefore many different species of trees, each with its complement of diseases. Some diseases are caused by existing, infectious pathogens with the potentials to cause extremely destructive epidemics, such as oak wilt and Dutch elm disease. Other diseases appear to be less pathogenic, but are increasing in incidence and severity with changes in climatic conditions.Also, the introduction of exotic, invasive pathogens on trees is an ongoing threat in Texas, with the potential for a huge impact on valuable landscape and forest trees. Monitoring and studying tree diseases, regardless of their origins, are warranted when they threaten the extremely valuable Texas woodlands, forests, and urban landscapes. This project addresses those threats with better detection, improved understanding of their epidemiology, and the ultimate goal of reducing their impact. New and refined disease prevention and control methods resulting from these studies will be made available to our clientele through educational outreach activities.
Objective 1: Survey for important Texas tree diseases to detect new threats and measure the relative impacts of existing diseases. A hierarchical approach must be used to gather survey data at different scales. County Extension Agents and their volunteers will be trained to assist with statewide monitoring for new and emerging pathogens. Training of arborists, landscape professionals, nurserymen, and natural resource managers through workshops, websites and various educational outputs will also alert practitioners of threats. At a finer scale, there are prescribed survey protocols for detection of exotic pathogens with suspected routes of entry such as SOD and citrus greening(see the Forest Health Monitoring website http://www.fhm.fs.fed.us/sp/sod/sod.shtml and website of the USDA APHIS http://www.aphis.usda.gov/plant_health/plant_pest_info/citrus_greenin g/index.shtml). Objective 2: Determine factors critical to the initiation and development of important tree diseases in Texas. A study site was established in Brazos County, TX, in 2000 with the primary objective of assessing the roles of several variables implicated in predisposing or inciting post oaks (Quercus stellata) to infection by H. atropunctatum. This site provides an ideal location for the long-term study of decline because there is currently a high degree of decline-like mortality occurring. Trees were measured in 2000 for size, health, and presence of canker and a variety of other parameters. These plots will be re-surveyed to compare long-term trends in tree survival between healthy and declining trees in relation to the plot parameters. The protocols used in this site will be used as a model for further sites where tree mortality and the presence of contributing factors are increasing. Objective 3: Develop improved methods for detecting and controlling critical tree diseases in Texas. Currently, oak wilt is diagnosed by field symptoms and laboratory isolation of the pathogen. Our objective is to develop an efficient and specific molecular detection system using quantitative real-time polymerase chain reaction (QRT-PCR. Primers and fluorescent labeled probes specific for C. fagacearum will be designed using Primer Express software (Applied Biosystems, Carlsbad, CA 92008). The primer/probe sets will be tested using an Applied Biosystems 7300 real-time PCR System to detect the pathogen from cultured spore suspensions, purified target DNA, and closely related, non-target fungal species. Following the preliminary testing to verify the specificity and sensitivity of the primer/probe sets, sampling schemes will be carried out to test them on field samples. The next step in testing will be to work with the Texas Plant Disease Diagnostic Laboratory to test the technique on submitted samples under operational clinic conditions. Finally, commercial arborists will be enlisted to submit blind samples to determine whether the sampling methods and processing of suspect tissues will be consistent with field interpretations of knowledgeable practitioners.
Target Audience
The results of this project have reached a wide-ranging target audience, from research colleagues to undergraduate studentsand homeowners seeking assistance on diseases of their trees. This is possible because the PI has a three-way appointment in research, teaching and extension. Within the Texas A&M AgriLIfe Extension Service, the County Extension Agents and their volunteers (MasterGardeners) are targets for training on the recognition and control of tree diseases. Also, within AgrLIfe Extension, fellow Specialists are kept informed of the latest status of various threats to forest and shade trees in order to inform their own clenele. Scientists and Field Foresters with the Texas A&M Forest Service are also kept informed of progress on project activities. Policymakers with USDA APHIS and the Texas Department of Agriculture (TDA) are the recipients of regular reporting on the status of new and emerging diseases of trees in Texas. Inthe private sector, commercial arborists and landscape managers are regularly trained on relevant topics related to tree health. Finally, landowners and homeowners are in attendance at numerous meetings and workshopswith the intent tobetter understand how to manage the problems on trees that affect property values or ecosystem services. Results were also published in refereed journals to inform the broader scientific community on the distrubution and impact of relevant tree diseases in Texas and our response to the losses they are causing. Factsheets on various tree health issues published on the Texas A&M AgriLife Bookstore website are also reaching these same audiences.
Changes / Problems
New and emerging diseases and a changing climate are responsible for introducing novel pathogens in Texas. The unexpected discovery of the SOD pathogen, Phytophthora ramorum, in Texas nurseries has stimulated concerted efforts to monitor those nurseries and deal with the required regulatory response on the part of the US Forest Service and USDA APHIS. Changes in the survey regions for citrus greening have been made to respond to Hurricanes and the find of Citrus Canker, caused by Xanthomonas axonopodis citri in the Upper Gulf Coast of Texas. Following the historic drought of 2011 in Texas, post oak trees (Quercus stellata) began declining and dying at increased rates throughout the range of the tree in East and Central Texas. The public concern for losses of post oak required investigations and a coordinated educational response to explain the causes for the problem and management recommendations. A similar response was required for the fire fungus following the Bastrop forest fires in 2011 (see Accomplishments). Other changes throughout the project were the result of adapting to new opportunites to pursue tree health issues in Texas, such as funding and the establishment of new collaborative efforts. 1. Unexpected find of P. ramorum, 2. Development of increased mortality of post oak
Training & Professional Development
Training and professional development are an extremely important part of the project.Master Gardener volunteers with the Texas A&M AgrLife Extension Service in at least 6 counties are trained annually. County Extension Agents (CEAs) recieve specialized training on tree health issues to help them in dealing with tree diseases in their counties. Critical Point Inspectors with the Texas Department of Agriculture (TDA) receive two days of training in College Station, TX, annually and part of that training inculdes updates on existing and emerging tree diseases in Texas. As a member of the Texas Oak Wilt Task Force, the PI also meets with Texas Forest Service field foresters on the latest developments on research on oak wilt. The PI participates in two meetings sponsored by TFS and the Texas Chapter of the International Society of Arboriculture (ISA) to certify commercial arborists as participating in advanced training on oak wilt. Graduate students and undergraduate students participate in special topics courses in my lab. For example, an undergradate student conducted the research described above on strain relationships in isolates of Cryphonectria parasitica, the chestnut blight pathogen (she is now going on to graduate school at Penn State University). Technicians working on the project also participate in regular training.
Dissemination Streams
The PI participates in 20 - 25 meetings throughout Texas for direct contacts with wide variety of audiences. Webinars are also held with the same audiences when necessary. Additional, more formal meetings (3 - 5 annually) for training various professional personnel. Factsheets are written for distribution through the Texas A&M AgriLife Bookstore. The PI responds to 100 - 150 phone calls and email contacts concerning tree health problems and diagnoses of tree diseases annually. Another outlet for the project is a newsletter with the Texas Chapter of the International Society of Arboriculture. The PI also participates in the national eXtension Cooperative Extension System "Ask The Expert" feature sponsored by the USDA and NIFA. Tree issues also reach the public interest through various media outlets and even national media outlets regularly in Texas, where the PI is asked to respond on tree health concerns. For example, National Public Radio commented on the PI's remarks concerning a famous oak tree that survived Hurricane Harvey in Fulton, TX this past year (http://www.npr.org/2017/09/02/548076006/-the-big-tree-still-stands-in-texas) . The quotes were from an article/interview by Popular Science in Sept. 2017. The results of research are also distributed through the on line feature AgriLife TODAY published by the TAMU Department of Ag Communications that is picked up by international, national and statewide media outlets.
Next Reporting Steps
Nothing Reported