1. Glyphosate Weed resistance
and
Weed Resistance Management
in Europe
Prague , June 2011
Ivo Brants
Regulatory Sciences Lead, EMEA

2. EMEA Context / Stakes
European
Directives
Water Country specifics
framework – Example France WRM
Water
quality Stewardship and
Sustainable FTO
Ecophyto Action plans
Use of 2018
Pesticides
Nitrate Inter-
directive crops
STAKES
1. Re-Positioning the uses of Roundup in sustainable agronomic systems
2. Helping our customers to position/justify the uses of Roundup in the
context of chemical restrictions

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. Shorten the Learning Curve on
Weed Management in the Future
Minor
Understand adjustments
all the tools to rates and
Begin that can be timings of
experimenting used herbicides
with residual to manage system and
No proactive the weeds,
products. management
change to and have
A complete practices.
herbicide implemented
weed
program. a systems
management
Assume The approach to
program is not
escapes are resistant manage
implemented
due to missed weeds or the them.
applications. spread to appropriate
larger areas
herbicide was
of the field.
not use.

6. 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 not worked:
– Long-term field studies nor routine monitoring of grower fields
are effective for either objective
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 Courtesy B. Johnson
Baseline studies are only needed when the
performance of a herbicide in not clearly understood
– glyphosate performance is well known.

7. Monitoring, reporting and reaction to changes of
performance
Grower Initial investigation with retailer,
performance Monsanto and grower
enquiry
Likely performance issue
(application, rate & timing, …)
Possible resistance
Remedial treatment recommendation from Field test assuming possible resistance,
Monsanto looking for management for the issue
Follow-up to ensure Further investigation of the case
effective control obtained (green-house efficacy, heritability tests,…)
Confirmation that resistance
Resistance confirmed
is not involved
Implementation of mitigation plan
Opportunity to train on Publication and notification to registration
Good Agricultural Practices bodies
Monitoring and follow-up in next seasons

8. Glyphosate Resistance – reported as well as allegations
Not on map, CZ republic:
Conyza canadiensis (railways)
France
Lolium rigidum
Conyza sumatriensis ??
Italy:
Spain: Greece
Portugal: Lolium rigidum
Lolium rigidum Conyza bonariensis
Lolium rigidum
Lolium multiflorum
Conyza bonariensis ??
Conyza bonariensis
Conyza canadensis Israel:
Conyza sumatriensis Lolium rigidum
Conyza bonariensis
8

9. Resistance Mechanisms are not Equal in
Magnitude or Probability
Target Site Mutations
• Weak to IMMUNE
• ALS, ACCase,
•Photosystem 2
•DNA
Metabolism Exclusion
• Weak Resistance • Weak Resistance; Very Rare
•ALS, ACCase, •Active (sequestration)
•Photosystem 2 •Passive (cuticle )
•DNA
•Most others Combinations Possible
11/6/2008 MONSANTO CONFIDENTIAL 9

10. Glyphosate Resistance Mechanisms
Exclusion
Target Site Extracellular
• Hypersensitive, excission
Mutations
• Pro106X 1
4 •Slow across
2 plasmalema
2 2
Over Expression 0
• Copy number
Intracellular
• Expression level
• Vacuole accumulation
Metabolism ~8X Single gene, Dominant
• Legumes
• Very SLOW
Combinations Known
10

11. 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
“Does cutting herbicide rates threaten the sustainability
of weed management in cropping systems?”
Michael Renton, et al 2011,
Journal of Theoretical Biology 283 (2011) 14–27
– Rate is also a factor related to weed
shifts

12. Factors associated with glyphosate
resistance development
No alternative control
methods
European cases are only present in perennial and non crop situations.
Arable crops in Europe are not a problem so far. 12

13. Control recommendations example Conyza
Optimum stage for treatment: Rosette Stage
Or seedling or flowering (at higher rates) but not stem extension
Best with low water volume < 200 lts/ha
Best results from rosette applications in early spring
Conyza germinates from autumn to spring so mix of growth stages common –
low efficacy often not related to resistance

14. 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 80% GA S
n
Target Site GA R
Percent Control
70% TN 1
60% TN 2
MS
50%
Azlin
40% TN 1 Fit
Sequestration Metabolism 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…..

15. Different registration even within the TNV segment
Example Italy
HRAC group Active ingredient Citrus Pome fruits Olives Vineyard
A Fluazifop-P-Butile X X X
A Cycloxydim X X
B Flazasulfuron X X X
D Diquat bromide X X X X
E Oxadiazon X X X X
E Oxyfluorfen X X X
G Glyphosat X X X X
K1 Pendimethalin X X
K1 Propyzamide X X
L Isoxaben X X X X
O MCPA X X X
O Fluroxypir X X X
O Dicamba X
16

16. 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.
11
8
Powles et al. 1997; 0.3 0.6
4
Dingle et al, 2003;
Biomass @ maturity (g/m2) Resistant seed bank (%)
Beckie et al. 2009;
Selection for Weed Resistance: Herbicide Rotation
and Mixture. Beckie et al. Weed Tech. 2009.

17. 8C
Resistant
Horseweed
is sensitive 24 hr
when cold 0.5 0.75 1 2 4 8
acclimated 0 lb/a
25C
12 hr
2 hr
Resistance mechanism is not ON in the cold
42 DAT

18. 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

19. 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

20. 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
General resistance statement (for all Roundup labels in EMEA)
Specific resistance statement (in addition to the general statement, for countries with
confirmed glyphosate resistant weed biotypes)
Provide management solutions, information, and training to farmers so they can
continue to be successful with the 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

21. Monsanto’s Commitment to Sustainable Agriculture
• PRODUCE MORE:
– Double corn, soy, cotton &
canola yields by 2030 vs. 2000
• CONSERVE MORE:
– Reduce aggregate use of key
resources by 1/3 per unit of
output by 2030 vs. 2000
• IMPROVE FARMERS’ LIVES:
– By boosting productivity and
efficiency, including reaching
more than 5M subsistence
farmers by 2020
Sustainable Weed Management

22. Thank you !