View
116
Download
0
Category
Preview:
DESCRIPTION
Phillp Pardey, University of Minnesota
Citation preview
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 MexicoMarch 24, 2014
Stem Rust – Global Assessment Summary
Climate suitabilityof stem rust
Suitable
Persists
Stem Rust – Global Assessment Summary
Climate suitabilityof stem rust
Suitable
Persists
A sustained investment of $51.1 million per year (2010 prices) in stem rust research could be justified economically
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?
Historical and Current Stripe Rust Threats
• Historically, stripe rust has mainly beenendemic only in cool climate regions
• In recent decades, stripe rust has spreadrapidly 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
Survey Responses—Causes of Expansion in Wheat Area with Losses Attributed to Stripe Rust
Survey QuestionsAggressiveness
changeClimate change
Susceptible wheat
Pathogen adaption
Other reasons*
Aggressiveness change 15Climate change 11 13Susceptible wheat 13 12 16Pathogen adaption 10 9 10 11Other 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
U.S. Wheat Yield Losses Attributed to Stripe Rust
Worldwide Stripe Rust Vulnerability (Beta version)
Persistently vulnerable area
Seasonally suitable area
Unaffected area
Area Share Output ShareSuitable Persists Suitable Persists
(Percentage)North America 41 0.9 46 1.2Australia 31 8.8 38 12Sub-Saharan Africa 24 23 19 18China 84 13 85 11India 2.5 1.3 0.9 0.5World 50 17 58 25
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
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
4.519
61
1964
1967
1970
1973
1976
1979
1982
1985
1988
1991
1994
1997
2000
2003
2006
2009
2012
Perc
ent L
oss
Average 0.54% per year
Average 0.15% per year
Average 1.5% per year
Global Stripe Rust Losses Estimates (Beta version)
Reference Period
CounterfactualLoss
Average annual losses(million metric tons)
Value of the annual losses (million U.S. $ per year)*
1961-84 none 0.88 $1571985-99 none 0.34 $612000-12 none 4.74 $848
Reference Period
CounterfactualPeriod
Losses Averted(million metric tons)
Value of the benefits(million U.S. $ per year)*
1961-84 1985-99 0.62 $1111985-99 1985-99 0 02000-12 1985-99 4.45 $797
* 2010 average US wheat prices
No Loss Counterfactual
Low Loss Counterfactual
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)
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 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 theapplication of effective fungicide (Chen 2005)
•Since 2000: stripe rust epidemics became increasingly important in PNW, south central states andthe 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
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
Thanks
Recommended