Global Status –

I. Glyphosate Resistant

Weeds and

II. Monsanto Stewardship II. Monsanto Stewardship

Programs

John Soteres, Ph.D.

Global Weed Resistance

Management Lead

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

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 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

Weed Resistance : Selection pressure

Resistant

"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.”

Courtesy of Ian Heap

Resistant

Resistance is detected when a high proportion (usually >15-30%) of the treated population isresistant to the herbicide.

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.

Glyphosate-Resistant Weeds - 201012 genus/ 17 species worldwide

Ambrosia spp.U.S.

Canada

Conyza spp.U.S.

Brazil

Argentina

Digitaria insularis (P)Paraguay

Brazil

Lolium spp. (A)U.S.

Brazil

S. Africa

Argentina

France, Italy, Spain

Australia

S. Halepense (P)Argentina

U.S.

Other annual grassesElucine sp. Malaysia, Colombia

Urochloa sp. Australia

Amaranthus spp.U.S.

Argentina

S. Africa

Israel

Spain

China

Other broadleavesParthenium sp. Colombia

Euphorbia sp. Brazil

Plantago sp. S. Africa

01/11/10JKS 6

Genus Year FirstReported

Country Situation

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

Reported Glyphosate Resistant Weeds

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

• Fallow– Glyphosate only

– “Low rates”

– Reduced tillage

• Orchards / Vineyards– Glyphosate only

Factors Associated with Evolution of GR Weeds

– Glyphosate only

– “Low rates”

– Reduced tillage

• GT Crops (gly use) – Glyphosate only

– “Low rates”

– Reduced tillage

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

GlyphosateGlyphosate--Induced Weed Shifts in GR corn or a Rotation of GR Induced Weed Shifts in GR corn or a Rotation of GR Corn, Corn, SugarbeetSugarbeet and Spring Wheat. (Wilson et. al. Weed Tech. and Spring Wheat. (Wilson et. al. Weed Tech. 2007)2007)

300

350

400

450

500

Lambsquarters

Density

(plants / m

2)

Chenopodium album

400

500

600

Density

(plant/m2)

Kochia scopia

1998 1999 2000 2001 2002 2003

Low GLY Rate 136 40 86 222 106 449

Labeled GLY Rate 144 18 37 26 9 141

0

50

100

150

200

250

300

Lambsquarters

(plants / m

2)

1998 1999 2000 2001 2002 2003

Low GLY Rate 490 50 4 35 4 4

Labeled GLY Rate 70 11 2 9 1 2

0

100

200

300

Kochia

Density

(plant/m2)

Conclusion: Low rates of glyphosate can cause species shifts.

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

• Integration of weed management options across a crop rotation system (multiple crops and fallow period)

RR Corn- YR 1

Acetanilide + Triazine

Glyphosate

RR Corn – YR 2

Acetanilide

Glyphosate + Auxins

RR Corn – RR 3

Acetanilide + Triazine

Glyphosate

Wheat

SU

Auxin

RR Soybeans

Glyphosate

RR Corn

Acetanilide

Glyphosate

Alternating Herbicides vs Mixtures (Postemergence example)

29

Field pennycress (Thlaspiarvense) response averaged over 4 yr of the experiment

No ALS ALS 1:4 ALS Mixture

Herbicide mixtures, whose

components are equally

effective against the target

weed species, are predicted

through model simulations to

delay resistance longer than

0,34

11

0,6

8

Biomass @ maturity (g/m2) Resistant seed bank (%)

Selection for Weed Resistance: Herbicide Rotation

and Mixture. Beckie et al. Weed Tech. 2009.

delay resistance longer than

rotations. (Dingle et al, 2003; Powles et al. 1997)

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. halepenseD. insularis

ACCase, Acetanilides (soybeans, cotton)SU, Acetanilides (corn)

Lolium spp. ACCase, paraquat, glufosinate (fallow, orchards, vineyards)ACCase, Acetanilides (soybeans, cotton)ALS, Acetanilides (corn)

01/11/10JKS 13

Conclusion: there are multiple options for controlling resistant populations.

Fields were across the road from each other. Two different farmers, two

different programs.

Managing Glyphosate Resistant Weeds:

Amaranthus palmerii in Cotton

Genuity™ Roundup Ready® Flex VarietyValor™ fb Cotoran™ fb Roundup PowerMAX™ +

Dual Magnum™

Widestrike® Genuity™Roundup Ready® Flex VarietyCotoran 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

Soybeans ‘08, ‘09

Crop Rotation with an aggressive weed management Crop Rotation with an aggressive weed management program can reduce seed bank significantly program can reduce seed bank significantly

Glyphosate-resistant

weeds prevalent

Alternative crop

‘08,

Soybeans ‘09

Soybeans ‘08, ‘09

Carthage, NC July 2009

II. Monsanto Stewardship

Programs

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

Conyza - RGS – Feb 2010

Low to Medium adoption

Conyza - RGS – Feb10

High adoption

Conyza - RGS – Feb 2009

Adoption of Best Management Practices in BrazilAdoption of Best Management Practices in Brazil

Research and DevelopmentSignificant 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

Target Site

MetabolismSequestration

Translocation

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 0.2 0.4 0.6 0.8 1 1.2 1.4

Perc

en

t C

on

trol

Glyphosate (kg a.e./ha)

GA S

GA R

TN 1

TN 2

MS

Azlin

TN 1 Fit

TN 2 Fit

MS Fit

Azlin Fit

Monsanto works closely with Academics around the world to answer

the key questions…..

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: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

Baseline studies are only needed when the performance of a herbicide in not clearly understood

– with glyphosate since performance is well known.

Courtesy B. Johnson

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

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 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

Thank You

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 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)

Evidence of Success of Education Programs in the U.S.

Best PracticesAlways or

Often SometimesRarely or

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%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