The projects listed below are those in which the Rocky Mountain Research Station, RWU-4152 is currently involved by participation of Brian Geils as a technical representative or cooperator. Although these projects are administratively distinct, the research is well integrated, the outcome of one project supports work in another projects. In each narrative, I briefly describe the justification and objectives of the project, identify principle cooperators, and provide links to published results. Cooperator and other sites describe their program and present additional information on white pine blister rust, genetics, and pathology.
White pine blister rust requires attention in the Southwest (New Mexico and Arizona) for several reasons. Cool mountain temperatures and frequent summer rains permit development of the blister rust in the numerous locations where susceptible Ribes and white pines are found (Van Arsdel and others 1989). Outbreaks in the Southwest not only threaten local populations and ecosystems but may allow development of new races of the rust and spread into Mexico (Geils 2001). Because the rust is a recent and expanding invasive in the region (Geils 2000), the emphasis of research and management is on an understanding of the potential for intensification, spread, and impact of blister rust under various forest management regimes applicable to Southwestern conditions (Dahms and Geils 1997). This project is a cooperative effort of the Rocky Mountain Research Station (RWU-4152), Southwest Region (Forest Health), and Forest Health Technology Enterprise Team (Quantitative Analysis) (previously including financial support from the Special Technology Development Program). The specific objectives are to develop a hazard rating system and evaluate disease threat across the region (Geils and others 1999). Central to these objectives are studies on outbreak dynamics (incidence and severity), meteorology (relation to phenology and dispersal), and Ribes (identification, distribution, and pathology).
There are numerous studies and reports for blister rust in the northern Rocky Mountains and on whitebark pine (see annotated bibliographies on The Dehiscent Peridium page). Recently, concern over high elevation white pines (whitebark pine, limber pine, and bristlecone pine) has extended to the central and southern Rocky Mountains (Smith and others 1999, Harris 1999, 2000) and Intermountain region (Smith and Hoffman 2000). Blister rust had been known for many decades in southern Wyoming. It appears to have been in northern Colorado for several decades as well; the first damage and distribution survey was conducted in June, 1999. Further spread of the pathogen in Colorado could result from not only from long-distance aerial dispersal of spores but also from infected nursery stock (Jacobi and Koski n.d.). Several new projects investigating the distribution, ecology, reproduction, and pest damage of white pines in the Rocky Mountain Region [PIs: let me know if you would like me to include a reference to your study]. One study for which I am a cooperator is a Special Technology Development Program project lead by the Forest Health Protection (FHP) staff from the Rocky Mountain (R2 FHP) and Intermountain Regions (R4 FHP) and principle conduct by Colorado State University (W.R. Jacobi). Significant support for this project is provided from the Quantitative Analysis Program, Forest Technology Enterprise Team.
The objective of the project is to apply and refine methodologies from previous work on southwestern and whitebark pines to new and existing plots for assessing where limber and bristlecone pines might be threatened and which control methods are likely to be effective. The project uses geographic information system technology for mapping site and stand features which relate to rust severity. These site and stand features include information on land form, vegetation, climate, stand history, and proximity to Ribes. My participation is focused on consultation for study and sample design and support for meteorological monitoring. Along with Eugene P. Van Arsdel, I am involved in preparation of a field guide on the Ribes of Colorado and New Mexico, with information on identification, distribution, and importance to blister rust epidemiology (see annotated bibliography on Ribes). We are also scouting southern Colorado and adjacent regions to assess rust hazard and potential for spread.
In the Greater Yellowstone area (GYA), white pine blister rust is a serious threat to whitebark and limber pines. Distribution patterns of the disease and hosts are patchy. Gradients of disease incidence allow for an examination of biological and environmental factors which may limit pathogen spread and intensification. As contribution to a Masters study at the University of Montana (Maria Newcomb, graduate student of Diana Six), we are engaged in a research joint venture on Ribes ecology and pathology in the GYA. Specifically, we are investigating the ecology, distribution, and phenology of Ribes and blister rust to better explain variation in rust incidence and severity from information on host distribution (ecologically and spatially) and meteorology (weather and climate).
Van Arsdel and others (1979) speculate that blister rust may have spread from the Sierra Nevada of California to the Sacramento Mountains of New Mexico by long-distance, aerial transport. An understanding of this process is especially important for monitoring and protection of white pine resources in the Southwest, Rocky Mountains, and the Mexican Sierra Madre. The objective of this study is evaluate the possibility of blister rust spread from California to New Mexico through development of a meteorological model based on historic records and concepts of air mass transport. The project is funded by the Forest Health Technology Enterprise Team (Harold Thistle) and conducted by the Center for Climatic Research, Synoptic Climatology Lab (Laurence Kalkstein, PI; Trina Frank). Preliminary results suggest atmospheric condition for long-distance transport are were not uncommon from 1965 to 1972. (The annotated bibliography on distribution and spread identified some relevant literature on the subject.)
In order to devise appropriate management policies, we need a good understanding of the history, present conditions, and potential for blister rust development. Previous, cooperative work by Det Vogler on the population genetics of stem rusts and a molecular detection kit for rusts of ribes provides a basis for continued research on the biogeography and phylogeny of Cronartium. [Det Vogler has conducted research at the University of California, Department of Plant and Molecular Biology and is now employed at the Institute of Forest Genetics.] Our present work includes a review of the history of blister rust spread in the Pacific and interior Southwest and development of a genetic library for the genus and other rusts infecting ribes. These studies offer better ecological and evolutionary knowledge as a basis for comparative studies (native verse exotic rust behavior), evaluation of control tactics (e.g., ribes eradication), and subject-matter synthesis.
Ribes species and cultivars exhibit significantly different pathologies following exposure to blister rust (see annotated bibliography on Ribes). Some currants and gooseberries are genetically immune to infection; others show a range of susceptibility to infection, rate of disease development, and capacity for supporting development of the spore stage infecting white pines. Understanding these differences is important for assessing the hazard of native and cultivated ribes to white pine populations. These differences are due to environmental and genetic factors (hosts and fungus) and their interactions. One goal of horticultural breeding is to include blister rust resistance in development of commercial varieties of currants and gooseberries, but resistance is usually tested against only those rust populations occurring in the local region. Varieties, however, could be planted in other regions and respond differently. In this broad (North American), cooperative study, a series of "common garden" plots are established which include a set of reference clones expected to show a range of resistance to Cronartium ribicola. Each garden would be maintained by a study participant; the use of a common set of reference clones and procedures should increase the opportunity for meaningful, geographic comparisons. Although this project is still being organized, several organizations include within their program foundation studies for this work. They also provide at their site relevant information on ribes cultivation, pests, and genetics.
USDA Agriculture Research Service, National Clonal Germplasm Respository
Ribes, Pines, and White Pine Blister Rust Conference. K. Hummer and R. Sniezko.
8-10 September 1999. Corvallis, OR.
http://www.ars-grin.gov/cor/wpbrmeet/
This meeting brought together foresters, horticulturists, breeders, growers and others to discuss
Ribes, pines, and white pine blister rust and to develop suggestions for minimizing white pine blister
rust incidence as Ribes cultivation increases in North America.
Abstracts and participants.
USDA Forest Service, Pacific Northwest Region, Dorena Tree Improvement Center
Program to Develop White Pine Blister Rust Resistance in Oregon and Washington for Sugar Pine
(Pinus lambertiana) and Western White Pine (Pinus monticola).
http://www.fs.fed.us/r6/dorena/rust.htm
Genetics, ribes: publications, photos.
USDA Forest Service, Rocky Mountain Research Station, Forestry Sciences Laboratory--Moscow, ID.
Research on white pine blister rust, especially genetics and epidemiology.
http://forest.moscowfsl.wsu.edu/
Introductory pages for research are linked under projects on Microbial
Processes and on Forest Ecosystem Processes.
USDA Forest Service, Pacific Southwest Research Station, Institute of Forest Genetics
Research focused on understanding the molecular basis of genetic resistance
to white pine blister rust.
http://dendrome.ucdavis.edu/Sugar_pine/
Home page for white pine rust resistance project.
NRC Canadian Forest Service, Pacific Forestry Centre, Forest Pathology Research
Includes a program of research on white pine blister rust.
http://www.pfc.cfs.nrcan.gc.ca/pathology/pathology_e.html
Introductory page for the pathology research program (pages for stem
diseases under construction).
USDA Forest Service Rocky Mountain Research Station, Flagstaff Lab