DOCSLIB.ORG

Sounding the Alarm on Global Stem Rust

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Sounding the Alarm on Global Stem Rust Foreword Norman E. Borlaug Stem rust is a catastrophic disease because of its ability to cause complete annihilation of wheat crops over wide areas. The use of genetic resistance in the major stem rust-prone regions of the world and the organized distribution of resistant germplasm through the International Rust Nursery scheme supported by the USDA and the Rockefeller Foundation, and later replaced by the CIMMYT nursery network, provided ongoing and updated sources of resistant germplasm to the international breeding community. In return, collaborating groups gave feedback on the responses of materials in their respective regions. During the late 1950s and early 1960s, great emphasis was placed on data that came from Kenya, Egypt, and southern Africa. The widespread use of stem rust resistant cultivars such as Red Egyptian, Kenya Farmer, Africa 43 and later, lines like Kenya Page and Africa Mayo, points to the key role of East Africa in the development of genetic resources that led to the global decline of stem rust. The stem rust threat was a primary reason for the establishment of the Rockefeller Foundation- sponsored program in Mexico, the predecessor of CIMMYT. The semi-dwarf, stem rust resistant, widely adapted spring wheat germplasm generated by this program led to the Green Revolution. Much of the material possessed the historically durable “Sr2 complex” from Hope and other well-known stem rust resistance genes. The widespread use of the 1BL.1RS translocation with Sr31 and its continuing stem rust protection on a worldwide basis has led to complacency throughout the wheat community. The discovery of race Ug99 with virulence for Sr31 and other important genes in Uganda in 1999, and possibly earlier in Kenya, was a reminder of the pathogen’s ability to respond, but little seems to have happened in breeding programs until the emergence of current concerns following the continued incidence and spread of race Ug99 in Eastern Africa. A major objective of this report is to assess global vulnerability to stem rust if race Ug99continues to spread. Most of the countries and regions responding to a series of questions relating to their specific situations indicated resistance to stem rust was no longer a leading breeding objective. Several noted that routine surveys were detecting increasing incidences of stem rust, associated with ill-advised use of susceptible varieties. Epidemics occur as a consequence of the use of widely popular very susceptible cultivars. The dynamics of rust epidemics are very much like those of forest or bush fires. The ingredients of fires (and rust epidemics) are fuel (area and distribution of susceptible material, degree of susceptibility), favorable climate conditions (optimum temperatures and moisture), number of ignition points (amount of initial inoculum), air movement, and complacency. Once started, both are difficult to stop. The prospect of a stem rust epidemic in wheat in Africa, Asia and the Americas is real and must be stopped before it causes untold damage and human suffering. i ACKNOWLEDGEMENTS The support of the Rockefeller Foundation in making this assessment possible is acknowledged with appreciation. The team also appreciated the keen interest and availability of the Directors and staff of the Ethiopian Agricultural Research Organization (EARO) and the Kenya Agricultural Research Organization (KARI). The foresight of CIMMYT and ICARDA in commissioning this report is commended and the support of CIMMYT’s offices in both Ethiopia and Kenya is gratefully acknowledged. Dr. Chris Dowswell contributed language for the foreword and other sections of the report. Finally, our Panel and everyone that we encountered during the course of this assessment appreciated the role of Dr. Norman Borlaug in bringing this problem to the attention of the international community. ii CONTENTS Page FOREWORD.............................................................................................................................................. i ACKNOWLEDGEMENTS ..................................................................................................................... ii SUMMARY AND RECOMMENDATIONS...........................................................................................1 CHAPTER 1 – WHEAT STEM RUST....................................................................................................3 1.1 The disease......................................................................................................................................3 1.2 Epidemiology..................................................................................................................................4 1.3 Virulence.........................................................................................................................................4 1.4 Race Ug99.......................................................................................................................................4 1.5 Evolution of new races and dispersal (migration path)...................................................................5 CHAPTER 2 – KENYA AND ETHIOPIA ASSESSMENT...................................................................7 2.1 Ethiopia ...........................................................................................................................................7 2.2 Kenya ..............................................................................................................................................8 2.3 Current and potential economic and social impacts in SSA ...........................................................9 - Ethiopia.......................................................................................................................................11 - Kenya..........................................................................................................................................12 CHAPTER 3 – VULNERABILITY OF OTHER GEOGRAPHICREGIONS ..................................15 3.1 Africa ............................................................................................................................................15 3.2 Asia ...............................................................................................................................................15 3.3 Europe ...........................................................................................................................................16 3.4 The Americas ................................................................................................................................16 3.5 Australia and New Zealand...........................................................................................................17 3.6 Conclusion ....................................................................................................................................17 CHAPTER 4 – STRATEGIES FOR CONTROL.................................................................................18 4.1 Pathogen monitoring .....................................................................................................................18 4.2 Genetic resistance, diversity and utilization..................................................................................18 4.3 Breeding for resistance with emphasis on durable type................................................................19 4.4 Emergency control measures ........................................................................................................20 4.5 Seed multiplication and distribution .............................................................................................20 4.6 Socio-economics ...........................................................................................................................20 4.7 Human resources...........................................................................................................................21 4.8 Infrastructure.................................................................................................................................21 4.9 Reporting and Communication .....................................................................................................21 4.10 Resources for International Agricultural Research Centers..........................................................21 REFERENCES.........................................................................................................................................23 APPENDICES..........................................................................................................................................25 Appendix I -- Panel Members....................................................................................................................25 Appendix II -- Persons Contacted............................................................................................................. 25 Appendix III -- Contributors........................................................................................................26 iii SUMMARY AND RECOMMENDATIONS The rusts (Puccinia spp.) have been a scourge on humankind since the beginning of historical time. Many epidemics have been recorded over the past 150 years, in the near and far east, Europe, and the Americas. Several devastating rust epidemics have resulted in major famines in Asia and grain losses at a massive scale in North America in 1903 and 1905 and 1950-54. For
Load more

Recommended publications
  • Current Status of Wheat Stem Rust Race Ug99 in South Africa
    Current status of wheat stem rust race Ug99 in South Africa Stem rust (black rust) is an important disease of bread wheat in South Africa. It is frequently found in the winter rainfall wheat growing regions of the Western Cape, sometimes reaching epide mic levels and causing significant economic loss. Susceptible cultivars could suffer more than 35% yield loss. The main sign of stem rust is the development of dark-red, elliptical pustules (masses of spores) mainly on the stem, and sometimes on the leaf and head of wheat. Dr Tarekegn Terefe (PTKST), 2SA88+ (TTKSF+) and 2SA42 (PTKSK). ARC-SMALL GRAIN, BETHLEHEM Race TTKSF (virulent on resistance genes Sr9e and Sr38) was first detected in SA in 2000 and LTHOUGH RESISTANT CULTIVARS pro- has dominated the stem rust population over Avide effective stem rust control, the fungus the last 20 years. This race is similar to TTKSP, ex- that causes stem rust frequently acquires new cept for its avirulence on Sr24. The widespread virulence to overcome the resistance in exist- occurrence of TTKSF can be mainly attributed to ing cultivars. The appearance, adaptation and its virulence on several resistance genes and the spread of the stem rust race Ug99 (TTKSK) high- cultivation of susceptible wheat cultivars in the lights the importance of stem rust variability in Western Cape, where stem rust regularly oc- global wheat production. curs. In addition to its broader virulence, TTKSF Ug99 is a highly virulent race which was probably possesses other fitness traits which detected in Uganda, East Africa in 1999. Ug99 may have contributed to its predominance over overcame the resistance gene Sr31 which had the past several years.
    [Show full text]
  • Mapping Non-Host Resistance to the Stem Rust Pathogen in an Interspecific Barberry Hybrid Radhika Bartaula1, Arthur T
    Bartaula et al. BMC Plant Biology (2019) 19:319 https://doi.org/10.1186/s12870-019-1893-9 RESEARCH ARTICLE Open Access Mapping non-host resistance to the stem rust pathogen in an interspecific barberry hybrid Radhika Bartaula1, Arthur T. O. Melo2, Sarah Kingan3, Yue Jin4 and Iago Hale2* Abstract Background: Non-host resistance (NHR) presents a compelling long-term plant protection strategy for global food security, yet the genetic basis of NHR remains poorly understood. For many diseases, including stem rust of wheat [causal organism Puccinia graminis (Pg)], NHR is largely unexplored due to the inherent challenge of developing a genetically tractable system within which the resistance segregates. The present study turns to the pathogen’salternate host, barberry (Berberis spp.), to overcome this challenge. Results: In this study, an interspecific mapping population derived from a cross between Pg-resistant Berberis thunbergii (Bt)andPg-susceptible B. vulgaris was developed to investigate the Pg-NHR exhibited by Bt. To facilitate QTL analysis and subsequent trait dissection, the first genetic linkage maps for the two parental species were constructed and a chromosome-scale reference genome for Bt was assembled (PacBio + Hi-C). QTL analysis resulted in the identification of a single 13 cM region (~ 5.1 Mbp spanning 13 physical contigs) on the short arm of Bt chromosome 3. Differential gene expression analysis, combined with sequence variation analysis between the two parental species, led to the prioritization of several candidate genes within the QTL region, some of which belong to gene families previously implicated in disease resistance. Conclusions: Foundational genetic and genomic resources developed for Berberis spp.
    [Show full text]
  • 2019 Small Grains Report Southcentral and Southeast Idaho Cereals Research & Extension Program
    Research Bulletin 202 January 2020 2019 Small Grains Report Southcentral and Southeast Idaho Cereals Research & Extension Program Juliet Marshall, Belayneh Yimer, Tod Shelman, Linda Jones, Suzette Arcibal, Jon Hogge, Margaret Moll, Chad Jackson and Katherine O’Brien Cover Images: Top: Wheat field in the Squirrel area outside of Ashton, Idaho. Bottom left to right: Idaho Falls Spring Nurseries, Fusarium Head Blight (Fusarium graminearum) on wheat and barley, Aphids on wheat, Hessian fly pupae on wheat, 2019 field demonstration day at Aberdeen R & E Center, Idaho, and lodged wheat field near Shelly, Idaho. Photo credit: Juliet Marshal. Southcentral and Southeastern Idaho Cereals Research and Extension Program http://www.uidaho.edu/extension/cereals/scseidaho Published and distributed by the Idaho Agricultural Experiment Station, Mark McGuire, Director, University of Idaho College of Agricultural and Life Sciences, Moscow, Idaho 83844-2337. The University of Idaho has a policy of nondiscrimination on the basis of race, color, religion, national origin, sex, sexual orientation, gender identity/expression, age, disability or status as a Vietnam-era veteran © 2020 by the University of Idaho ii ACKNOWLEDGEMENTS Idaho wheat and barley producers, through About the Authors cooperative research and extension grants from the Idaho Wheat and Barley Commissions, provided Juliet Marshall is the Cereals Cropping Systems partial funding for these small grain performance Agronomist & Pathologist with the UI SC & SE evaluations. Support was also provided by the Idaho Cereals Extension Program. University of Idaho Cooperative Extension System, Belayneh Yimer is a Postdoc/Research Support the Idaho Agricultural Experiment Station, and by fees Scientist with the UI SC & SE Idaho Cereals paid by plant breeding companies.
    [Show full text]
  • Stem Rust on Wheat and Barley
    Identification and Management of Stem Rust on Wheat and Barley Stem rust, leaf rust, and stripe rust comprise a production. The first of these races, known as ‘Ug99’, complex of diseases that reduces wheat and barley was originally detected in Uganda, Kenya, and grain production. These rust diseases occur in nearly Ethiopia. Since this initial detection, additional races all areas of the United States and Canada. The of the fungus have been reported and are further importance of any member of the complex at a given complicating efforts to contain the problem. location is determined by specific interactions with If these new races spread to North America, current wheat varieties, they may threaten wheat crop growth stage, and and barley production. weather conditions. Why does the genetic In preparation for the Stem rust has been resistance appear to fail? possible introduction of present in North America Currently genetic resistance is an effective these new races of stem for hundreds of years. means of managing the rust diseases of rust, a number of critical A series of particularly wheat and barley. Because the populations questions arise regarding severe outbreaks occurred the most effective ways during the early 1930s and of the fungi that cause rust diseases can to identify, monitor, and 1950s. These outbreaks change and adapt to the resistance genes of manage the disease. This caused serious yield loss in current varieties, the durability of this genetic publication answers these many parts of the United resistance has been problematic. These critical questions with the States and Canada with changes occur when naturally occurring best available information the greatest losses in the genetic changes allow members of the about the emerging threat.
    [Show full text]
  • Putting Ug99 on the Map: an Update on Current and Future Monitoring*
    Putting Ug99 on the map: Introduction Detection of stem rust race TTKSK (Ug99) from Uganda An update on current and in 1998/99 (Pretorius et al. 2000) highlighted not only the extremely high vulnerability of the global wheat crop future monitoring* to stem rust but also a lack of adequate global systems to monitor such a threat. The expert panel convened 1 2 3 4 D.P..Hodson ,.K..Nazari ,.R.F..Park ,.J..Hansen ,.P.. by Dr Borlaug in 2005 in response to Ug99 (CIMMYT 4 5 6 4 7 Lassen ,.J..Arista ,.T..Fetch ,.M..Hovmøller ,.Y.Jin ,.Z.A.. 2005) recognized this deficiency and recommended that Pretorius8.and.K..Sonder5 monitoring should be addressed as a priority. The global wheat community responded to this recommendation with Abstract a Global Cereal Rust Monitoring System (GCRMS) being Detection of stem rust race TTKSK (Ug99) from developed by an international consortium within the frame Uganda in 1998/99 highlighted not only the extremely work of the Borlaug Global Rust Initiative (BGRI) (Hodson et high vulnerability of the global wheat crop to stem al. 2009). rust but also a lack of adequate global systems to Concern over races within the Ug99 lineage is justified monitor such a threat. Progress in the development by the well documented historical capacity for stem rust and expansion of the Global Cereal Rust Monitoring to cause severe devastation in all continents in which System (GCRMS) is described. The current situation wheat is grown (see Dubin and Brennan 2009; Hodson regarding the Ug99 lineage of races is outlined and 2011).
    [Show full text]
  • Special Session: UG 99 Status, Management and Prevention
    Special Session: UG 99 Status, Management and Prevention Wafa Khoury, AGP-FAO Keith Cressman, AGP-FAO Amor Yahyaoui, ICWIP-ICARDA FAO, Rome 9 April 2008 Current Importance of Wheat Rusts Region Yellow Rust Leaf Rust Stem Rust Australasia Major Local Minor East Asia Major Local Minor South Asia Major Local Minor West Asia Major Local Minor Central Asia Major Major Local Russia/Ukraine Local Major Minor Middle East Major Local Minor North Africa Major Local Minor Eastern Africa Major Local Major Southern Africa Major Local Local Eastern Europe Local Local Minor Western Europe Major Local Minor North America Major Major Minor Central America Major Local Minor South America Local Major Local Special session: UG 99 Status, Management and Prevention Trans-boundary wheat rust Historical information shows records of wind borne spores moving across continents, although shorter distance movements are more common – often within distinct pathozones (or epidemiological regions?). Virulent strain of wheat stripe rust ( Puccinia striiformis ) referred to as Vir.Yr9, appeared in Kenya 1980 then was recovered in Ethiopia in East Africa in 1986 , Pakistan and Nepal in 1990 and reached South Asia in 1993 Spread of Yellow rust followed prevalent current . Special session: UG 99 Status, Management and Prevention Yellow rust (Vir. Yr9) spread 1986-1998 Heavy yield losses were incurred along the pathway of yellow rust from Egypt to Pakistan Special session: UG 99 Status, Management and Prevention Trans-boundary wheat rust In 1999 a new strain of stem rust (Puccinia graminis fsp tritici ) occurred in Uganda, known as Ug99 (www.globalrust.org ). Ug99 represents a much greater threat than Vir Yr9, Estimated 80% of current global wheat varieties are susceptible New Stem rust race: UG99 Stem rust Ug99 followed the expected Ug99-TTKS migration but moved faster to Yemen Ug99: Global threat Can spread from East Africa to Asia, Europe, Australia, America World wheat tsunami???? Such scary reach-out may increase the wheat price in the speculative global market.
    [Show full text]
  • Stripe Rust Appears in Idaho According to Juliet Marshall with University of Idaho Extension, Stripe Rust Has Found Its Way to Western Idaho (Parma)
    Forward to a friend or colleague Stripe rust appears in Idaho According to Juliet Marshall with University of Idaho Extension, stripe rust has found its way to western Idaho (Parma). Below is an image of stripe rust on UI Magic CL+ (via Oliver Neher). The growth stage of winter wheat in that area is past the window of fungicide application, and is currently in grain fill. Spring wheat is still vulnerable and susceptible varieties should be scouted for the appearance of stripe rust. In the Magic Valley and into eastern Idaho, winter wheat is heading and susceptible varieties are still vulnerable to significant yield loss associated with stripe rust infection. Stripe rust reaction of last year’s varieties in the Extension Variety Trials is reported in the 2019 Small Grains Report available online at https://www.uidaho.edu/extension/cereals/scseidaho. Please note that while some varieties were reported as resistant in 2019, race changes were reported in California by Dr. Mark Lundy (UC Davis pathologist) in this year’s crop; therefore scouting of all varieties is recommended this season. Please report observations to UI Extension in order to help tracking of the in- season spread. The weather forecast for this and especially next week is very conducive to stripe rust spread and infection. According to Xianming Chen, a research plant pathologist with the USDA Agricultural Research Service and Washington State University, wheat stripe rust has been reported in Oregon, Washington, Texas, Louisiana, Oklahoma, California, Kansas, Kentucky, Virginia, Illinois; and Idaho. Barley stripe rust has been reported in California, Oregon, and Washington.
    [Show full text]
  • 9B Taxonomy to Genus
    Fungus and Lichen Genera in the NEMF Database Taxonomic hierarchy: phyllum > class (-etes) > order (-ales) > family (-ceae) > genus. Total number of genera in the database: 526 Anamorphic fungi (see p. 4), which are disseminated by propagules not formed from cells where meiosis has occurred, are presently not grouped by class, order, etc. Most propagules can be referred to as "conidia," but some are derived from unspecialized vegetative mycelium. A significant number are correlated with fungal states that produce spores derived from cells where meiosis has, or is assumed to have, occurred. These are, where known, members of the ascomycetes or basidiomycetes. However, in many cases, they are still undescribed, unrecognized or poorly known. (Explanation paraphrased from "Dictionary of the Fungi, 9th Edition.") Principal authority for this taxonomy is the Dictionary of the Fungi and its online database, www.indexfungorum.org. For lichens, see Lecanoromycetes on p. 3. Basidiomycota Aegerita Poria Macrolepiota Grandinia Poronidulus Melanophyllum Agaricomycetes Hyphoderma Postia Amanitaceae Cantharellales Meripilaceae Pycnoporellus Amanita Cantharellaceae Abortiporus Skeletocutis Bolbitiaceae Cantharellus Antrodia Trichaptum Agrocybe Craterellus Grifola Tyromyces Bolbitius Clavulinaceae Meripilus Sistotremataceae Conocybe Clavulina Physisporinus Trechispora Hebeloma Hydnaceae Meruliaceae Sparassidaceae Panaeolina Hydnum Climacodon Sparassis Clavariaceae Polyporales Gloeoporus Steccherinaceae Clavaria Albatrellaceae Hyphodermopsis Antrodiella
    [Show full text]
  • Norman Borlaug
    Norman E. Borlaug 1914–2009 A Biographical Memoir by Ronald L. Phillips ©2013 National Academy of Sciences. Any opinions expressed in this memoir are those of the author and do not necessarily reflect the views of the National Academy of Sciences. NORMAN ERNEST BORLAUG March 25, 1914–September 12, 2009 Elected to the NAS, 1968 He cultivated a dream that could empower farmers; He planted the seeds of hope; “ He watered them with enthusiasm; He gave them sunshine; He inspired with his passion; He harvested confidence in the hearts of African farmers; He never gave up. The above words are those of Yohei Sasakawa, chairman of Japan’s Nippon Foundation, written” in memory of Norman E. Borlaug. The author is the son of Ryoichi Sasakawa, who created the Sasakawa Africa Association that applied Borlaug’s work to Africa—the focus of much of the scientist’s efforts in his later years. The passage By Ronald L. Phillips reflects Borlaug’s lifelong philosophy and his tremendous contributions to humanity. His science of wheat breeding, his training of hundreds of developing-country students, and his ability to influence nations to commit to food production are recognized and appreciated around the world. Borlaug was one of only five people to have received all three of the following awards during their lifetimes: the Nobel Peace Prize (1970); the Presidential Medal of Freedom (1977); and the Congressional Gold Medal (2007), which is the highest award that the U.S. government can bestow on a civilian. (The other four were Mother Teresa, Martin Luther King, Nelson Mandela, and Elie Weisel.) Borlaug was elected to the National Academy of Sciences of the United States in 1968 and in 2002 received its Public Welfare Medal, which recognizes “distinguished contributions in the application of science to the public welfare.” At a White House ceremony in 2006, President George W.
    [Show full text]
  • Status of Wheat Rust Research and Control in China
    Status of wheat rust research and control in China Zhensheng Kang*, Jie Zhao, Dejun Han, Hongchang Zhang, Xiaojie Wang, Chenfang Wang, Qingmei Han, Jun Guo & Lili Huang *College of Plant Protection and Shaanxi Key Laboratory of Molecular Biology for Agriculture, Northwest A&F University, Yangling, Shaanxi 712100, P. R. China e-mail: [email protected] Abstract In China, wheat is grown on approximately 24 million hectares with an annual yield of 100 million tonnes. Stem rust, caused by Puccinia graminis f. sp. tritici, is a threat mainly to spring wheat in northeastern China. Leaf rust, caused by P. triticina, occurs on crops in the late growth stages in the Yellow-Huai-Hai River regions. Stripe rust, caused by P. striiformis f. sp. tritici (Pst), is destructive in all winter wheat regions and is considered the most important disease of wheat in China. During the last 20 years, widespread stripe rust epidemics occurred in 2002, 2003, and 2009, and localized epidemics occurred in many other years. In recent years, major yield losses were prevented by widespread and timely applications of fungicides based on accurate monitoring and prediction of disease epidemics. A total of 68 Pst races or pathotypes have been identified using a set of 19 differential wheat genotypes. At present, races CYR32 and CYR33 virulent to resistance genes Yr9, Yr3b, Yr4b, YrSu and some other resistance genes are predominant. Moreover, these races are virulent on many cultivars grown in recent years. Of 501 recent cultivars and breeding lines 71.9% were susceptible, 7.0% had effective all-stage resistance, mostly Yr26 (= Yr24), and 21.2% had adult-plant resistance.
    [Show full text]
  • Pandemics Aren't Just for People: How Disease Can Affect Crops And
    practice applicationsTOPICS OF PROFESSIONAL INTEREST Pandemics Aren’t Just for People: How Disease Can Affect Crops and the Food Supply n the most unlucky of days in Experts interviewed predicted a rise many within the general public might 1844, a fungus now referred to in cost and perhaps a shift in diet for not know his profession exists. “I can’t Oas Phytophthora infestans made most Americans as the disease moves tell you how many times I go to a its way through the rolling hills of this way, but those in the developing party and tell someone what I do and Ireland after ravaging American countries could suffer famine, starva- they say, ‘plants get diseases?’ Yes, farms in the years immediately prior. tion, and forced migration, as they they get diseases just like we do.” Believed to have crossed the Atlantic have before. Studying, identifying, and helping on US ships bound for European And of course, while the threat of remedy those diseases is part of what ports, the disease is a water mold UG99 is yet being combated, history he does in addition to participation in which blights not only potatoes, but suggests other diseases are already the National Plant Diagnostic Sys- potentially tomatoes as well. But it on the way to replace it. tem. was the Irish potato crop which fell Wheat is a staple for most of the victim as the disease moved eastward world, used to create everything from into continental Europe, destroying UG99 flour to pasta, bread, crackers, and food production along the way.
    [Show full text]
  • EC1802 Reduce Black Stem Rust of Wheat, Oats, Barley, Rye J
    University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Historical Materials from University of Nebraska- Extension Lincoln Extension 5-1943 EC1802 Reduce Black Stem Rust of Wheat, Oats, Barley, Rye J. E. Livingston Follow this and additional works at: http://digitalcommons.unl.edu/extensionhist Livingston, J. E., "EC1802 Reduce Black Stem Rust of Wheat, Oats, Barley, Rye" (1943). Historical Materials from University of Nebraska-Lincoln Extension. 2732. http://digitalcommons.unl.edu/extensionhist/2732 This Article is brought to you for free and open access by the Extension at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Historical Materials from University of Nebraska-Lincoln Extension by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Reduce Black Stem Rust .;:t; of Wheat, Oats, Barley, Rye 180~ J E. Livingston ~ ) J Extension Plant Pathologist The University of Nebraska Agricultural College Extension Service and United States Department of Agriculture Cooperating W. H. Brokaw, Director, Lincoln, Nebraska Distributed in furtherance of Acts of May 8 and June 30, 1914 (5-43-20M) Acknowledgement is made to the Conference for the Pre­ vention of Grain Rust, Minneapolis, Minnesota, for assistance in preparation of illustrative material, and to the Division of Plant Disease Control, Bureau of Entomology and Plant Quar­ antine, Washington, D . C., for assistance in preparation of this circular. Two Important Sources of Stem Rust From Barberry rust organism is spread from the old straw, stubble 2. Blown in From Other Areas 1. and grasses of the past year to the green, growing In the spring, tiny stem rust spores become detached grain of the next year.
    [Show full text]