NCERA184: Management of Small Grain Diseases
(Multistate Research Coordinating Committee and Information Exchange Group)
NCERA184: Management of Small Grain Diseases
Duration: 10/01/2017 to 09/30/2022
Statement of Issues and Justification
Small grains, particularly wheat, barley, and oats are significant crops in many states east of the Rocky Mountains - hereafter referred to as eastern U.S. (source: USDA-NASS). Of these, wheat is the most economically important and multiple classes are grown in this region, including: hard red winter (southern and central Great Plains), hard red spring and durum (northern Great Plains), soft red winter (central and southeastern U.S.), and soft white winter (northeast and north central U.S.). There has also been an increase in acreage of hard white wheat planted in the Great Plains with the release of improved varieties. Barley, oats, and to a lesser extent rye and triticale are also regionally important in the eastern U.S. and represent significant crops in certain states (e.g. barley in North Dakota, oats in South Dakota and Oklahoma).
The combined value (farm gate) in 2015 for the grain from these crops was approximately $11.6 billion (source: USDA-NASS). The primary uses of these grains are: human consumption (flour, bran, etc.), livestock feed, and malting and brewing (barley). These crops may also be used for hay, straw, and silage production or even directly grazed (e.g. dual-purpose, graze-grain wheat). Additionally, small grains are being investigated for potential use in biofuel production as both grain-starch and cellulosic sources because they can often be grown in areas where corn and soybeans cannot, for example, winter wheat in the western Great Plains. Lastly, small grains may be used as cover crops in some regions (e.g. Mid-Atlantic, Upper Great Plains) as a means to reduce soil erosion and nutrient leaching into waterways. Consequently, seed production for wheat, barley, and rye cover crops continues to be an important aspect of small grain production in this region.
Production of small grains has declined substantially over the last 20 years in the United States for several reasons. First, the price paid for grain has changed little during that time and thus the value for several of these crops has actually declined when adjusted for inflation. To add to the financial issues, government subsidies for many of the small grains are less competitive than those for other crops like corn and soybean. Second, diseases continue to have a profound and negative affect on both grain yield and quality and shifts in agronomic practices have complicated disease management strategies further (see below), making it difficult to maintain profitability. Third, the massive expansion of genetically modified (GM) crops (i.e. corn and soybeans) has made small grains much less attractive to producers because of the relatively more complicated and expensive weed and pest management strategies sometimes required for small grains. Finally, small grains are currently less efficient than corn for biofuel (ethanol) production. When all of the above factors are considered, small grains are simply less competitive economically than corn and soybean for much of the eastern U.S. and thus their acreage has gradually declined. Several of these same factors may result in a future increase in the acreage planted with small grains. First, the increasing development of glyphosate (i.e. Round-Up) resistance in some weeds will likely impact annual acreage of corn and soybeans in the future and complicate future weed management strategies in these crops. Second, the lack of crop diversity has resulted in very short rotations that allow pest and pathogen populations to remain high and regularly impact yield. Finally, the increasing costs of fertilizer, pesticides, fuel, and scarcity of irrigation water in some regions is making it difficult for producers to maintain profitability, especially for corn. Lastly, the rapid expansion of biofuel generation using corn and soybean is diverting the grain from these crops away from human and livestock consumption. Small grains may be used to fill the niche left from the biofuel-associated changes in crop utilization as well as for biofuel production directly. Overall, the addition of small grains to current rotations would add diversity to the dominant cropping systems and potentially reduce the impact and severity of the pathogens and pests of all crops in the long term.
Other factors may result in increased acreage of small grains, particularly barley in the Northeast. For example, the craft beer industry in the United States has increased dramatically since 2007, with the number of breweries increasing from 1,460 to 4,656. An additional 2,200 operations are planned to open in the near future (brewersassociation.org. Accessed 8/1/16). Craft breweries currently employ an estimated 121,843 full-time and part-time workers in a variety of roles including many manufacturing jobs, all of which contribute significantly to the U.S. economy. This, in addition to local subsidies to promote the use and production of locally sourced malting barley, has resulted in a need for research on production practices, variety development, and pest management of malting barley in states where barley is typically grown for feed, such as Kentucky, New York, Virginia, Pennsylvania, Delaware, Maryland, and the New England states.
The agronomic practices utilized for growing small grains have changed dramatically in the last three decades as many growers are changing over to reduced tillage practices, planting earlier, and using shorter rotations to reduce soil erosion. Many are also intensively managing their crops by applying higher amounts of fertilizer, growth regulators, and pesticides to maximize yields. All of these factors have had profound effects on the incidence and severity of the diseases of small grains. The wheat residue-borne diseases, such as Fusarium head blight (FHB), tan spot, and Stagonospora diseases and barley residue-borne diseases net blotch, spot blotch and FHB, occur annually in much of the eastern U.S. and have a significant impact on both crop yield and quality. Epidemics of FHB in particular have devastated the wheat and barley crops in entire regions (e.g. the northern Great Plains and Northeast), resulting in millions of bushels in lost production, numerous farm and equipment sales, and disruption of entire rural communities. By gaining a better understanding of the epidemiology of the diseases of small grains in both current and emerging production systems, we can develop economically sound management strategies for producers.
In order for producers of small grains to remain profitable while addressing the future needs of consumers, the impact of current and emerging diseases on crop yield and quality must be addressed. Unfortunately, this is difficult not only because of changes in agricultural practices but also because many of the pathogens attacking these crops are dynamic in both their geographic distribution and ability to overcome many common sources of genetic resistance in current cultivars. For example, stripe rust of wheat was more of a curiosity than a concern in the Great Plains prior to 2001. Since then, a new population of the stripe rust pathogen adapted to warmer climates has emerged. This new population of stripe rust was also able to overcome many common sources of genetic resistance and has emerged as one of the most important diseases in the US. Epidemics of stripe rust in 2010, 2015, and 2016 resulted in more than $100 million in economics losses for producers. Other rust diseases of small grains, specifically leaf rust of wheat and crown rust of oats, continue to cause significant losses, even after many years of breeding efforts to improve the resistance in commercial varieties. This is partly due to cereal rusts' ability to change races over time.
In contrast to the aforementioned rust diseases, stem rust (caused by Puccinia graminis) has received very little attention from plant pathologists and breeders because it has been effectively controlled through stable host resistance and the barberry eradication program (which targeted the alternate host). As a result, a minimal effort has been put into the introgression of novel resistance genes for stem rust into small grains, particularly wheat. Thus a limited number of genes are deployed in the wheat varieties grown over large regions of the United States (e.g. the southern Great Plains) and throughout the world. A strain (Ug99) of P. graminis was identified in Africa that is virulent on the majority of the wheat and probably barley cultivars grown in the eastern U.S. As of February 2016, this strain has spread to 13 countries throughout Eastern and Southern Africa and the Middle East. A concern shared by both small grains researchers and stakeholders is that this strain will follow a similar migration pathway as that of Asian soybean rust or wheat stripe rust and enter the U.S. before wheat and barley breeders have had time to deploy effective resistance genes into commercially acceptable varieties. To complicate the issue further, the introduction of resistance to one disease rarely provides protection to other diseases and may even disrupt established resistance. For example, wheat breeders in much of the eastern U.S. have focused on developing resistance to FHB, an effort that has resulted in the release of several moderately resistant varieties in the past several years. Unfortunately this work has caused erosion in the level of resistance to stem rust, putting wheat at an increased risk to this potentially devastating disease. In summary, the combination of a susceptible crop and little probability of the release of resistant varieties in the next decade places wheat production in much of the U.S. at risk to the potentially devastating impact of a major stem rust epidemic.
Other diseases aside from rust pose a significant risk to wheat production in the United States and require better understanding of their epidemiology and management. Wheat blast, caused by the fungus Magnaporthe oryzae, was first identified in 1985 in Paraná State of Brazil. It recently spread to the important wheat-producing regions of South America. The disease was detected in Bangledesh in February, 2016 suggesting that the disease is spreading at a global scale. Yield losses from this disease can be greater than 75% in severely affected fields, causing annual yield losses in excess of 7.5 million acres where it occurs. Neither the wheat blast pathogen nor the disease has been detected within the U.S., but the potential for this to occur is high. Increased importation of agricultural products from Brazil enhances the chance for the accidental introduction of the wheat blast pathogen into the U.S. Consequently, continued research and communication among small grain scientists in this area is essential in ensuring rapid response to a potential outbreak and the development of tools to identify and manage this disease.
Increased emphasis on disease prevention and management will be needed to help small grain producers remain competitive in international markets, to assure an ample supply of high-quality grain for domestic consumption, and to minimize the impact of adverse environmental conditions on small grain production. Given the decline in overall support for research and extension activities related to diseases of small grains, individual states have fewer resources for either research on the diseases of small grains or to provide pertinent information for all diseases attacking these crops through the state supported extension programs.
The exchange of information and coordination of research and extension activities among small grain pathologists and individuals in related research programs in the region east of the Rocky Mountains will facilitate better management of small grain diseases. In addition to increased communication and collaboration among small grains pathologists of the eastern U.S., it is anticipated that this group will interact closely with members of the WERA97 (Diseases of Cereals), the Eastern Wheat Workers, and the Southern Small Grain Workers on common diseases of concern. The groups have recently held joint meetings (e.g. 2009 and 2011) and plan to continue these productive interactions during the next several years.
Better characterize best management practices for Fusarium Head Blight and leaf diseases in wheat and barley
Comments: We will continue to examine the roles of environment, variety, and chemical applications on management of important emerging or reemerging diseases in wheat and barley. In particular, we will evaluate best management practices for Fusarium Head Blight and leaf disease management across a range of environments and grain classes.
Conduct fungicide efficacy trials for diseases in small grains
Comments: We will continue to test and modify our national recommendations for fungicide efficacy and utility for disease control through yearly, state level fungicide efficacy trials.
Improve disease management through forecasting tools
Comments: We will continue to improve the Fusarium Head Blight prediction model through the use of coordinated, trials and data collection. We will work to help with the development of a stripe rust model with researchers at Kansas State University.
Procedures and Activities
Facilitate collaborative research on current and emerging diseases of small grains. In particular, members of NCERA184 are focused on several core sub-objectives including the integrated management of small grain diseases, fungicide efficacy trials for diseases of small grains, epidemiology and risk management, screening of uniform regional nurseries for resistance to economically important pathogens, and studies of the population biology of small grain pathogens. These continue to be the core of our group as they provide a mechanism for sustained efforts to best address the needs of stakeholders and also provide a framework for joint efforts (research and/or through discussions and meetings) with the following groups: WERA97 (Diseases of Cereals), Eastern Wheat Workers, and Southern Small Grain Workers. Furthermore, several of our objectives have also been recognized by other groups, including the Corn Disease Working Group and NCERA212 (Soybean Diseases) as models for ways to provide stakeholders the most relevant information.
a) Integrated Management of Select Wheat and Barley Diseases.
Characterization of best management practices for Fusarium Head Blight (FHB)
Studies have been conducted, and will be continuing, using a multi-state, multi-year coordinated mechanism to examine the impacts of i) level of varietal resistance, ii) fungicide applications, and iii) environmental conditions (especially temperature and relative humidity) on the severity of Fusarium head blight (FHB) in wheat and barley and the contamination of grain with mycotoxins, particularly deoxynivalenol. These studies have been routinely conducted in 12 states across 6 small grain market classes. Research to date has shown that combinations of cultivar resistance with properly-timed fungicide applications reduce the risk of both FHB and deoxynivalenol. However, this research needs to be tested across multiple grain categories and growing conditions. These trials also help provide both local and national data to support sub-objective (c) as a mechanism to improve forecasting for FHB in the U.S.
Better understanding best management practices for foliar diseases in wheat production systems
Several states (Ohio, Illinois, Indiana, Wisconsin) have commenced with coordinated trials with an explicit goal to develop thresholds for wheat diseases like Stagonospora leaf blotch using combinations of cultivar resistance and fungicide timing. Furthermore, coordinated studies examining the utility and efficacy of fungicide application programs for wheat and barley disease are underway in Delaware, Pennsylvania, Maryland, and Virginia. Oat crown rust integrated management trials are being conducted in Minnesota, North Dakota and South Dakota. Data from all projects will be shared with the NCERA 184 group and potentially expanded to include other production regions and grain classes.
b) Fungicide Efficacy Trials for Diseases of Small Grains.
Questions continue to be received regarding efficacy of fungicide products currently registered for control of diseases of small grains, the application timings that are most efficacious for disease control, and the amount of fungicides actually required to produce a high quality and profitable crop. As new products obtain approval through EPA, we need to be at the forefront for providing stakeholders the best information possible regarding the best management practices of such products. There has been coordinated effort through the U.S. Wheat and Barley Scab Initiative to conduct coordinated trials for Fusarium head blight, however; the majority of NCERA184 members also conduct fungicide efficacy trials for the small grains pathogens of economic importance in their states. These trials are important for several reasons, including the ability to provide EPA with necessary information for emergency registration of products (Section 18, for example tebuconazole). Most importantly, and as highlighted earlier in the paragraph, data from these trials are integrated into an annual update on fungicide efficacy. This latter output is an approach that both the Corn Disease Working Group and NCERA-137 (Soybean Diseases) use to provide producers with similar information in those crops, respectively.
c) Epidemiology and Risk Management
Members of the NCERA184 have collaborated on the development of Fusarium head blight risk assessment models. The risk assessment models are currently deployed in 30 states through a web interface (http://www.wheatscab.psu.edu/). In 2011, the NCERA184 committee enhanced the function of the disease prediction effort by establishing the FHB Alert System. The FHB Alert System sends commentary developed by disease specialists in each state to stakeholders via regional e-mail lists and text messages. These commentaries describe the current risk of disease and often provide management recommendations where appropriate. The value of this system can be seen by the fact that over 4300 people use the forecasting model on an annual basis and the estimated monetary impact of the model exceed $65 million. As indicated earlier, the ability to link coordinated research trials [sub-objective (a)] with the risk assessment models enables real-time validation of the model, thus providing researchers with mechanisms to examine and continue to improve model accuracy. Key advances that are continuing on the model development and refinements include enhancements to the web-based tools and smart phone applications that enable producers and other stakeholders the opportunity to access risk information in the field. In addition, the development of a weather-based forecasting model for stripe rust is currently underway in Kansas. Members of this group will work to assist in the development of this model and work to improve its accuracy and implementation. Screening of Uniform Regional Nurseries for Resistance to Economically Important Pathogens.
Members of the NCERA184 work closely with wheat geneticists and breeders in the identification, evaluation, genetics, introgression, and/or deployment of additional or novel sources of resistance to many of the small grains pathogens (e.g. soilborne wheat mosaic virus, Fusarium head blight, leaf rust, stripe rust, and powdery mildew). A substantial proportion of this effort involves the evaluation of Uniform Regional Nurseries, or similar collaborative screening arrangements like cultivar performance trials. We will continue to work closely with small grains breeders and evaluate such collaborative screening nurseries in order to identify and characterize disease resistance in advanced breeding lines. This has multiple benefits, including integration with sub-objectives (a) and (c) in terms of developing best management practices for small grain diseases as well as validation of forecasting risk models. Furthermore, this provides a mechanism for screening for resistance to new diseases or strains of existing pathogens such as the Ug99 strain of wheat stem rust, thus providing a link with sub-objective (e).
d) Studies of the Population Biology of Small Grains Pathogens.
The monitoring of the population biology of the pathogens of economic importance to small grains is extremely important as this provides a mechanism to identify changes in these populations that may impact the stability of resistance present in the cultivated varieties. Additionally, this information can be used to provide input for the prioritization of resistance introgression into adapted varieties and help guide varietal improvement programs overall. Furthermore, this provides a coordinated, national level system to look for exotic strains, such as the Ug99 strain of wheat stem rust. In collaboration with USDA-ARS scientists (Y. Jin, J. Kolmer, and X. Chen), as well as Kirk Broders (Colorado State University) samples of the major rust diseases of the small grains (e.g. leaf rust, stripe rust of wheat, crown rust of oats, etc) will be collected and submitted for race determination and other purposes. This project has been on-going for decades and represents a major effort to monitor the population/virulence structure of these extremely important and often yield-limiting pathogens.
Promote the exchange of information, techniques, fungicide efficacy results, disease resistant germplasm and pathogen cultures among small grain researchers in order to coordinate the development of integrated management strategies for important small grain diseases.
Members of the NCERA184 have a documented history demonstrating effective information exchange through the annual committee meeting and through national and regional plant pathology meetings. Furthermore, we maintain coordinated email discussions, including the wheat disease listserv (email@example.com) and cereal rust survey listserv (firstname.lastname@example.org). We have shown a desire to meeting jointly with sister programs such as WERA97 and the Eastern Wheat Workers and Southern Small Grain Workers and propose to continue to meet jointly with those groups when possible. On a national level, NCERA 184 group members serve as representatives for the National Wheat Improvement Committee and National Barley Improvement Committee. Lastly, we are working to use other forms of social media, such as twitter, to help with disease information dissemination as well as a tool for tracking disease development throughout the U.S.
Develop regional and national extension outreach materials to improve disease management and profitability of small grain producers.
Members of the NCERA184 have demonstrated an ability to work collaboratively on the production and dissemination of vital educational materials for use by producers and others in the small grain community. For example, the group recently worked to update, publish, and distribute two new small grain guides, “Diseases Affecting the Heads of Small Grains” and “Wheat Disease Identification.” Over 60,000 copies of these guides were produced and distributed to growers and agricultural professionals in over 29 states. Our desire to provide clientele with practical, updated, and timely educational materials will continue to be a central focus of the NCERA 184 group. We also continue to refine fungicide efficacy tables, which are distributed nationally, as well as important disease scouting and IPM guides.
Expected Outcomes and Impacts
- Coordination of research to evaluate BMP for FHB and foliar disease management across a range of grain classes Comments: We will work across state lines to develop replicated trials to better understand and develop best management practices for major diseases in wheat and barley.
- Develop national fungicide reccomendation guide and update annually
- Refine FHB model to improve estimations of risk and enhance usability.
- Assist in development of Stripe Rust forecasting model for the central Great Plains.
- Develop and publish updated wheat and barley disease management guides to promote the importance of disease identification.
Projected ParticipationView Appendix E: Participation
Information generated from this group will be shared with a diverse group, including growers, consultants, other agriculture industry personnel, and the scientific community, via a variety of means including: extension and risk forecasting websites, newsletters, email (e.g. listservs), grower-meetings, social media (Twitter and Facebook) and publication of multi-state extension bulletins.
Currently, two primary listservs exist (wheat disease listserv and cereal rust survey listserv) that enable collaboration and discussion amongst NCERA184 researchers. These are important components for discussing real-time issues in disease diagnostics or other observations in the small grain production areas.
Information pertaining to wheat diseases needs to be conveyed to the wheat production sector on a timely and cost effective basis. For example, the Penn State web page which provides a prediction tool for Fusarium head blight has expanded its coverage and accessibility to growers and crop consultants. ScabSmart was developed with the support of the U.S. Wheat and Barley Scab Initiative. Numerous members of NCERA184 participate in both efforts to provide best management practices and state specific commentary regarding the risk of FHB. New plans include the continued development and refinement of of smart phone tools for accessing risk information in the field.
Most states have a weekly online or print extension newsletter. Technologies such as the internet, online bulletins, print on demand, and grower hotlines are all methods that will be used to transmit disease management information quickly and effectively to producers. The majority of the infrastructure required for this activity is currently available through state-level extension services as well as federally funded projects (e.g. the US Wheat and Barley Scab Initiative, the USDA-CSREES PIPE, etc.) and we will continue to look for funding to continue such efforts.
There will be two officers for NCERA-184. A secretary will be elected at each annual meeting. The secretary records and distributes minutes of the annual meeting, submits the annual report, and then becomes chair of the committee for the following year. The chair directs the activities of the committee, serves as the liaison between the committee and the administrative advisor, and assists with or directs arrangements for the next annual meeting.