Global Status – I. Glyphosate Resistant Weeds II. Monsanto Stewardship Programs

1. Global Status –
I. Glyphosate Resistant
Weeds and
II. Monsanto Stewardship
Programs
John Soteres, Ph.D.
Global Weed Resistance
Management Lead

2. I. Glyphosate Resistant
Weeds
- Global Status
- Contributing Factors
- Management practices

3. Definitions:
Herbicide Resistance: "Herbicide resistance is the inherited ability of a plant to
survive and reproduce following exposure to a dose of herbicide normally
lethal to the wild type.”
– ‘dose of herbicide’ = Labeled Rate
– Minimum differential between ‘susceptible’ and ‘resistant’ populations is generally
considered to be 2X
Herbicide Tolerance: "Herbicide tolerance is the inherent ability of a species to
survive and reproduce after herbicide treatment. This implies that there was
no selection or genetic manipulation to make the plant tolerant; it is naturally
tolerant."
Hard-to-control: Weed species that tend to be more sensitive to rate, growth
stage and application conditions to achieve commercially acceptable
control.
– Hard-to-control does not equate to species most likely to develop resistance

4. Weed Resistance : Selection pressure
"Herbicide resistance is the inherited ability of a plant to survive and reproduce
following exposure to a dose of herbicide normally lethal to the wild type.”
Resistant
Resistance is detected when a high proportion
(usually >15-30%) of the treated population is
resistant to the herbicide.
Courtesy of Ian Heap

5. Resistance has been reported to all herbicide
classes
• First herbicide resistance reported in 1957 to 2,4-D
• First triazine resistance reported in 1968
• To date resistance has been confirmed in 195 species (115
dicots and 80 monocots), 346 resistance biotypes
This website requires that a species be tested to confirm that the resistance is at
levels above the labeled rate and is heritable.

6. Glyphosate-Resistant Weeds - 2010
12 genus/ 17 species worldwide
Ambrosia spp.
U.S. Conyza spp.
Canada U.S.
Brazil
Argentina
Amaranthus spp. S. Africa
U.S. Israel Other broadleaves
Parthenium sp. Colombia
Spain
Euphorbia sp. Brazil
China
S. Halepense (P) Plantago sp. S. Africa
Argentina
U.S.
Lolium spp. (A)
U.S.
Brazil
Digitaria insularis (P) Other annual grasses
S. Africa
Paraguay Elucine sp. Malaysia, Colombia
Argentina
Brazil Urochloa sp. Australia
France, Italy, Spain
Australia
01/11/10JKS 6

7. Reported Glyphosate Resistant Weeds
Genus Year First Country Situation
Reported
Lolium (2 spp.) 1996 / 2001 Australia / Chile Fallow / Orchards
Eleucine 1997 Malaysia Orchards
Conyza (2 spp.) 2000 / 2003 USA / S. Africa RR soybeans / Vineyards
Plantago 2003 S. Africa Vineyards
Ambrosia (2 spp.) 2004 USA RR soybeans
Parthenium 2004 Colombia Orchards
Amaranthus (2 spp.) 2005 USA RR soybeans / RR cotton
Sorghum (perennial) 2005 Argentina RR soybeans
Digitaria (perennial) 2006 Paraguay RR soybeans
Euphorbia 2006 Brazil RR soybeans
Echniochloa 2007 Australia Fallow
Urochloa 2008 Australia Fallow
Kochia 2009 USA Fallow, RR corn, RR soybeans

8. Factors Associated with Evolution of GR Weeds
• Fallow
– Glyphosate only
– “Low rates”
– Reduced tillage
• Orchards / Vineyards
– Glyphosate only
– “Low rates”
– Reduced tillage
• GT Crops (gly use)
– Glyphosate only
– “Low rates”
– Reduced tillage

9. Factors Associated with Evolution of GR
Weeds: “Low Rates”
• “Low Rates” ( application rate
and/or applications beyond
recommended growth
stages)
– For some species, rate is a
factor related to the
development of resistance
– Rate is also a factor related to
weed shifts

10. Glyphosate-
Glyphosate-Induced Weed Shifts in GR corn or a Rotation of GR
Corn, Sugarbeet and Spring Wheat. (Wilson et. al. Weed Tech.
2007)
Chenopodium album Kochia scopia
500 600
450
400 500
Lambsquarters Density
350
Kochia Density
400
(plants / m2)
(plant/m2)
300
250 300
200
200
150
100 100
50
0
0 1998 1999 2000 2001 2002 2003
1998 1999 2000 2001 2002 2003
Low GLY Rate 490 50 4 35 4 4
Low GLY Rate 136 40 86 222 106 449
Labeled GLY Rate 70 11 2 9 1 2
Labeled GLY Rate 144 18 37 26 9 141
Conclusion: Low rates of glyphosate can cause species shifts.

11. Weed management diversity is the foundation of
proactive resistance management:
Definition of Diversity
Use of multiple methods to manage weed populations
Key Elements
• Integration of in-crop weed management options
– Multiple modes-of-action in tank mix or in sequence
– Use of cultural practices to supplement herbicide use
RR Corn- YR 1 RR Corn – YR 2 RR Corn – RR 3
Acetanilide + Acetanilide +
Triazine Acetanilide
Triazine
Glyphosate Glyphosate +
Glyphosate
Auxins
• Integration of weed management options across a crop rotation system
(multiple crops and fallow period)
Wheat RR Soybeans RR Corn
SU Glyphosate Acetanilide
Auxin Glyphosate

12. Alternating Herbicides vs Mixtures
(Postemergence example)
Herbicide mixtures, whose Field pennycress (Thlaspi
components are equally arvense) response averaged
effective against the target over 4 yr of the experiment
weed species, are predicted No ALS ALS 1:4 ALS Mixture
through model simulations to
29
delay resistance longer than
rotations. (Dingle et al,
2003; Powles et al. 1997) 11
8
4
0,3 0,6
Biomass @ maturity (g/m2) Resistant seed bank (%)
Selection for Weed Resistance: Herbicide Rotation
and Mixture. Beckie et al. Weed Tech. 2009.

13. Managing Glyphosate-Resistant Weeds
Resistant Species Options
Amaranthus spp. Triazine, HPPD (corn)
PPO (cotton)
PPO, Triazines, ALS (soybeans)
Conyza ALS, PPO (vineyards, orchards)
Auxins (2,4-D, dicamba) (corn, preplant)
ALS, Triazines, PPO (soybeans)
Ambrosia spp. PPO, ALS, Triazines (soybeans)
HPPD, ALS, Triazines (corn)
S. halepense ACCase, Acetanilides (soybeans, cotton)
D. insularis SU, Acetanilides (corn)
Lolium spp. ACCase, paraquat, glufosinate (fallow, orchards, vineyards)
ACCase, Acetanilides (soybeans, cotton)
ALS, Acetanilides (corn)
Conclusion: there are multiple options for controlling resistant populations.
01/11/10JKS 13

14. Managing Glyphosate Resistant Weeds:
Amaranthus palmerii in Cotton
Fields were across the road from each other. Two different farmers, two
different programs.
Genuity™ Roundup Ready® Flex Variety Widestrike® Genuity™Roundup Ready® Flex
Valor™ fb Cotoran™ fb Roundup PowerMAX™ + Variety
Dual Magnum™ Cotoran fb Roundup PowerMAX + Dual Magnum
fb Roundup PowerMAX + Staple™ fb Ignite®
Labeled Use Rates of All Products, Missouri Bootheel 2009; Dow AgroSciences and Bayer Crop Science do not endorse
the use of Ignite over the top of Widestrike cotton

15. Crop Rotation with an aggressive weed management
program can reduce seed bank significantly
Glyphosate-resistant
weeds prevalent
Soybeans ‘08, ‘09
Alternative crop
‘08,
Soybeans ‘09
Carthage, NC July 2009

16. II. Monsanto Stewardship
Programs

17. Robust Stewardship Programs are key to effectively
managing weed shifts and the development of
herbicide resistance in agriculture…..
Key Elements of a Stewardship Program:
• Research
• Monitoring
• Grower/Retailer Education and Training
Adoption of Best Management Practices in Brazil
Conyza - RGS – Feb 2009 Conyza - RGS – Feb 2010 Conyza - RGS – Feb10
High adoption
Low to Medium adoption

18. Research and Development
Significant resources are focused on herbicide resistance:
– Mechanisms of resistance
– Weed biology / Modeling
– Best practices to retard development of resistance and management of
existing problems
– Discovery/development of new options
100%
90%
Translocatio
n
Target Site 80% GA S
GA R
Percent Control
70% TN 1
60% TN 2
MS
50%
Azlin
Sequestration Metabolism 40% TN 1 Fit
TN 2 Fit
30%
MS Fit
20% Azlin Fit
10%
0%
0 0.2 0.4 0.6 0.8 1 1.2 1.4
Glyphosate (kg a.e./ha)
Monsanto works closely with Academics around the world to answer
the key questions…..

19. Weed Resistance Monitoring:
Objectives: Early detection of new species and spread
to new areas
Options:
– Long-term field studies
– Monitor grower fields and take weed counts
– Monitor grower performance issues with appropriate follow up
– Random collection of weed seed and grow-outs
What has been useful:
– Coordinated efforts between Industry, Farm Consultants, and
Universities to monitor grower performance for early detection
– Random collection of weed seed and growouts is effective to
identify the spread of resistance
What has not worked:
– Long-term field studies nor routine monitoring of grower fields
are effective for either objective Courtesy B. Johnson
Baseline studies are only needed when the
performance of a herbicide in not clearly
understood
– with glyphosate since performance is well known.

20. Stewardship Guidelines
General principles of herbicide resistance management:
• Apply integrated weed management practices. Use multiple herbicide modes-of-
action with overlapping weed spectrums in rotation, sequences, or mixtures.
• Use the full recommended herbicide rate and proper application timing for the hardest
to control weed species present in the field.
• Scout fields after herbicide application to ensure control has been achieved. Avoid
allowing weeds to reproduce by seed or to proliferate vegetatively
• Monitor site and clean equipment between sites.
Summary
• Significant progress has been made in the consistency of messages

21. Principles of Monsanto’s Weed Resistance Stewardship
Program:
Commitment to follow-up on performance complaints and situations in which
weed resistance is suspected
Transparency (a clear and open process)
Where resistance has been confirmed by established valid criteria, we
acknowledge and communicate and recommend practices to manage the
resistant weed
Provide management solutions, information, and training to farmers so they
can continue to be successful with the Roundup Ready System and
glyphosate herbicide
Maintain close cooperation with all outside parties involved with weed
resistance (Industry, Academics, Commodity Groups, Regulators) to provide
the best solutions to growers
Maintain a leadership position in research on glyphosate resistant weeds
and best management practices
Discover and provide new options for more effective weed control
management

22. Thank You

23. Proactive versus Reactive
Management in U.S. Soybeans
1. Current management of waterhemp (Amaranthus sp.) in
Soybeans
– Sequential postemergence applications of glyphosate
– Total cost of $10/A
2. Strategy to delay the selection of glyphosate-resistant waterhemp -
pre/post
– Canopy XL @ 4.5oz/A preemergence ($8.66/A)
– Roundup Weathermax @ 22 oz/A postemergence ($10.21/A)
– Total cost of $14/A
3. Strategy to control PSII/ALS/glyphosate-resistant waterhemp -
pre/post in soy
– Boundary 7.8EC @ 1.25 pt/A PRE ($12.14/A)
– Flexstar @ 24 oz/A PRE ($19.03/A)
– Fusion @ 12 oz/A PRE ($14.66/A) or RWM @ 22 oz/A
– Total cost of $46/A
Strategies to Manage Amaranthus sp in Soybeans in IL (B. Young, 2009)

24. Evidence of Success of Education
Programs in the U.S.
Always or Rarely or
Best Practices Often Sometimes Never
Scout before 83% 11% 5%
Scout after 81% 15% 4%
Start with clean field 75% 13% 12%
Control early 89% 9% 2%
Control escapes 79% 15% 6%
Clean equipment 25% 20% 54%
New seed 94% 3% 2%
Different modes 39% 33% 28%
Supplemental tillage 21% 26% 53%
Use label rate 93% 4% 1%
Frisvold et al, 2009