The Global Occurrence and Economic
Consequences of Stripe Rust in Wheat
Philip Pardey, Yuan Chai, Jason Beddow,
Terry Hurl...
Stem Rust – Global Assessment Summary
Climate suitability
of stem rust
Suitable
Persists
Stem Rust – Global Assessment Summary
Climate suitability
of stem rust
Suitable
Persists
A sustained investment of $51.1 m...
Implications for Stripe Rust
What is the global extent of this disease?
• Where is it likely to occur and persist?
What ...
Historical and Current Stripe Rust Threats
• Historically, stripe rust has mainly been
endemic only in cool climate region...
Survey Responses—Causes of Expansion in Wheat
Area with Losses Attributed to Stripe Rust
Survey Questions
Aggressiveness
c...
U.S. Wheat Yield Losses Attributed to Stripe Rust
Worldwide Stripe Rust Vulnerability (Beta version)
Persistently vulnerable area
Seasonally suitable area
Unaffected area
A...
Source: Pardey et al. (2013)
Average 2.5% per year
Stochastic Structure of U.S. Losses Attributed to Stem Rust
Average 0.2...
Stochastic Structure of U.S. Losses Attributed to Stripe Rust
The changing structure of stripe rust epidemics
 1961-1984:...
Global Stripe Rust Losses Estimates (Beta version)
Reference
Period
Counterfactual
Loss
Average annual losses
(million met...
Approach
 Estimate of annual investments to avert projected losses (costs) attributable to
stripe rust through to 2048
 ...
U.S. Wheat Yield Losses Attributed to Stripe Rust
Changing Spatial Structure of Losses
•Before 1959: no reported losses attributed to stripe rust
•1959-1984: wheat stripe r...
Summing Up
 Earlier assessment suggests that around $50 million per year be invested in
research to avert prospective glo...
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The Global O currence and Economic Consequences of Stripe Rust in Wheat

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Phillp Pardey, University of Minnesota

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The Global O currence and Economic Consequences of Stripe Rust in Wheat

  1. 1. The Global Occurrence and Economic Consequences of Stripe Rust in Wheat Philip Pardey, Yuan Chai, Jason Beddow, Terry Hurley and Darren Kriticos University of Minnesota BGRI 2014 Technical Workshop Ciudad, Obregon Mexico March 24, 2014
  2. 2. Stem Rust – Global Assessment Summary Climate suitability of stem rust Suitable Persists
  3. 3. Stem Rust – Global Assessment Summary Climate suitability of stem rust Suitable Persists A sustained investment of $51.1 million per year (2010 prices) in stem rust research could be justified economically
  4. 4. Implications for Stripe Rust What is the global extent of this disease? • Where is it likely to occur and persist? What share of global wheat area and production is susceptible to the disease?  What is the likely global losses in wheat production associated with this disease?  What are the global research investment implications of this disease?
  5. 5. Historical and Current Stripe Rust Threats • Historically, stripe rust has mainly been endemic only in cool climate regions • In recent decades, stripe rust has spread rapidly to areas previously unaffected Before 2000 After 2000 0 Not recorded, or no response 1 Rare 2 Localized in some seasons 3 Localized in most seasons 4 Widespread in some seasons 5 Widespread in most seasons N = 29
  6. 6. Survey Responses—Causes of Expansion in Wheat Area with Losses Attributed to Stripe Rust Survey Questions Aggressiveness change Climate change Susceptible wheat Pathogen adaption Other reasons* Aggressiveness change 15 Climate change 11 13 Susceptible wheat 13 12 16 Pathogen adaption 10 9 10 11 Other reason* 3 4 5 3 5 *Other reasons proposed by survey respondents include cropping system, lack of crop rotation, presence of green bridge, poor management, and insufficient control strategies. N = 29 respondents
  7. 7. U.S. Wheat Yield Losses Attributed to Stripe Rust
  8. 8. Worldwide Stripe Rust Vulnerability (Beta version) Persistently vulnerable area Seasonally suitable area Unaffected area Area Share Output Share Suitable Persists Suitable Persists (Percentage) North America 41 0.9 46 1.2 Australia 31 8.8 38 12 Sub-Saharan Africa 24 23 19 18 China 84 13 85 11 India 2.5 1.3 0.9 0.5 World 50 17 58 25
  9. 9. Source: Pardey et al. (2013) Average 2.5% per year Stochastic Structure of U.S. Losses Attributed to Stem Rust Average 0.29% per year
  10. 10. Stochastic Structure of U.S. Losses Attributed to Stripe Rust The changing structure of stripe rust epidemics  1961-1984: significant yield losses  1985-1999: use of resistant cultivars and fungicide  Since 2000: new stripe rust pathotypes 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 1961 1964 1967 1970 1973 1976 1979 1982 1985 1988 1991 1994 1997 2000 2003 2006 2009 2012 PercentLoss Average 0.54% per year Average 0.15% per year Average 1.5% per year
  11. 11. Global Stripe Rust Losses Estimates (Beta version) Reference Period Counterfactual Loss Average annual losses (million metric tons) Value of the annual losses (million U.S. $ per year)* 1961-84 none 0.88 $157 1985-99 none 0.34 $61 2000-12 none 4.74 $848 Reference Period Counterfactual Period Losses Averted (million metric tons) Value of the benefits (million U.S. $ per year)* 1961-84 1985-99 0.62 $111 1985-99 1985-99 0 0 2000-12 1985-99 4.45 $797 * 2010 average US wheat prices No Loss Counterfactual Low Loss Counterfactual
  12. 12. Approach  Estimate of annual investments to avert projected losses (costs) attributable to stripe rust through to 2048  Ninety five percent chance of realizing a modified internal rate of return of at least 10 percent per year 1961-84 Stochastic Loss Structure $8.0 million per year, or 4 cents per hectare 2000-12 Stochastic Loss Structure $27.8 million per year, or 12 cents per hectare Comparative Information  Economically justified investment in stem rust was $51.1 million per year  U.S. wheat farmers spent $15.75 per hectare on seed Economically Justifiable R&D Investment (Beta estimates)
  13. 13. U.S. Wheat Yield Losses Attributed to Stripe Rust
  14. 14. Changing Spatial Structure of Losses •Before 1959: no reported losses attributed to stripe rust •1959-1984: wheat stripe rust caused significant yield losses in the Pacific North-West (PNW) region •1985-1999: yield losses were generally low because of the use of resistant cultivars and the application of effective fungicide (Chen 2005) •Since 2000: stripe rust epidemics became increasingly important in PNW, south central states and the central Great Plains, causing severe damage. 0 5 10 15 20 25 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 % U.S. Wheat Yield Losses: Pacific North West (PNW) vs. Non-PNW PNW&CA % Loss Non PNW&CA % Loss
  15. 15. Summing Up  Earlier assessment suggests that around $50 million per year be invested in research to avert prospective global losses from stem rust, double what is being spent of late  Evidence suggests a change in the spatial pattern and magnitude of wheat yield losses attributable to stripe rust  Beta assessment suggests that around $28 million per year be spent to alleviate global losses from stripe rust, substantially more than would have been justified several decades ago  On-going work is assessing the interplay between the spatial pattern of losses, the spatial extent of those losses, and the research investment implications of these more recent changes
  16. 16. Thanks

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