Areawide Suppression of
European Corn Borer with Bt
Corn Reaps Benefits for NonBt Growers
Paul D. Mitchell
Ag & Applied Economics, UW-Madison
Central Wisconsin Processing Crops
March 9, 2011
Goal Today
 Quick overview of Hutchison et al. (2010) in
Science
 Where we are going next in this research


Estimate value of market level benefits of Bt
corn and where economic surplus went
Estimate impacts of Bt corn/ECB suppression
on Midwestern vegetable production
Areawide Suppression of European Corn Borer
with Bt Corn Reaps Benefits for Non-Bt Growers
 Widespread Bt corn planting in Midwest has
suppressed ECB population
 Creates value for both Bt & non-Bt corn acres

$6.9 billion in MN, WI, IL, IA & NE since 1996
 More of the value went to non-Bt corn acres
 75% to non-Bt acres in MN/WI/IL
 Bt corn more valuable than originally thought
 Stewardship/IRM even more important
 Nations give up more value than realize if do
not use Bt corn
ECB Suppression and Bt Corn
 WI and IL collecting ECB larval population data from





hundreds fields annually since mid-1940’s when pest
first arrived in region
MN did same starting in 1963
Shows population decline in recent years
% corn acres planted to Bt corn has increased since
1996 when released
Statistical analysis showed ECB population decline
associated with increased Bt corn planting
Suppression not clear as ECB lives on 100+ plants,
many crops (e.g., sweet corn, green bean, potato)
Bt Corn Adoption Rate by State
80%
70%
Bt Corn Adoption Rate
60%
IL
MN
WI
IA
NE
50%
40%
30%
20%
10%
0%
1995
1997
1999
2001
2003
2005
2007
2009
ECB Population Data 1940 to 2009
450
WI
IL
MN
2nd Genr. ECB larvae/100 plants
400
350
300
250
200
150
100
50
0
1940
1950
1960
1970
1980
1990
2000
2010
ECB Population Data Since 1990
450
WI
IL
MN
2nd Genr. ECB larvae/100 plants
400
350
300
250
200
150
100
50
0
1990
1992
1994
1996
1998
2000
2002
2004
2006
2008
2010
Annual Benefits
 Estimated annual yield losses implied by ECB
larval populations, then total corn produced
 Corn Produced with Observed ECB
 Corn Produced with Long-term Average ECB
 Corn Produced with No ECB
 Benefit: corn produced x price that year
 Bt Corn Benefit: Difference between No ECB
and Observed ECB
 Non-Bt Corn Benefit: Difference between
Observed ECB and Long-term Average ECB
Annual Benefits to Bt Corn Acres
175
Annual Benefit ($ Million)
150
IL
MN
WI
125
100
75
50
25
0
-25
1995
1997
1999
2001
2003
2005
2007
2009
Annual Benefits to Non-Bt Corn Acres
250
225
IL
MN
WI
Annual Benefit ($ Million)
200
175
150
125
100
75
50
25
0
1995
1997
1999
2001
2003
2005
2007
2009
Cumulative Benefits MN, WI, IL
4,000
Cumulative Benefit ($ Million)
3,500
Bt
non-Bt
Total
3,000
2,500
2,000
1,500
1,000
500
0
1995
1997
1999
2001
2003
2005
2007
2009
Implications
 Bt corn more valuable than originally thought
 Stewardship/IRM even more important

Saving a more valuable tool
 Nations give up more value than realize if do
not use Bt corn

Giving up a more valuable tool
Summary
 Similar analysis in IA and NE, but ECB data
not as extensive, so done separately
 Overall, ECB suppression creates value for
both Bt & non-Bt corn acres

$6.9 billion in MN, WI, IL, IA & NE since 1996
 More of the value went to non-Bt corn acres
 75% to non-Bt acres in MN, WI, and IL
 50% to non-Bt acres in IA and NE
 Why? Non-Bt acres had some ECB control at
zero cost, but Bt growers had to pay tech fee
With Tech Fee, Bt and Non-Bt about
Same, Total Benefit about $8.5 Billion
9,000
Cumulative Benefits ($ Million)
8,000
7,000
Non-Bt
Bt + Tech
Total
6,000
5,000
4,000
3,000
2,000
1,000
0
1995
1997
1999
2001
2003
2005
2007
2009
Estimated Total Tech Fees Paid in MN,
WI, IL, IA, NE by Year
200
Tech Fees Paid ($ Million)
180
160
140
120
100
80
60
40
20
0
1995
1997
1999
2001
2003
2005
2007
2009
What’s Next?
 Estimate total economic surplus generated by
Bt corn, including ECB suppression effect
 Portion of benefits captured by Bt farmers,
non-Bt farmers, by seed companies and
consumers and how changes over time
 Effect of Bt corn and ECB suppression on
corn prices
 Benefits of ECB suppression for vegetable
crops: sweet corn, potatoes, green beans
Questions or Comments?
Paul D. Mitchell
UW-Madison Ag & Applied Economics
Office: (608) 265-6514
Cell: (608) 320-1162
Email: pdmitchell@wisc.edu
Extension Web Page:
www.aae.wisc.edu/mitchell/extension.htm