ibrants_wrm_prague_june11
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Glyphosate Weed resistanceand
Weed Resistance Managementin Europe
Prague , June 2011
Ivo BrantsRegulatory Sciences Lead, EMEA
EMEA Context / Stakes
EuropeanDirectives
Stewardship and FTO
Action plans
Water framework
SustainableUse of
PesticidesNitrate
directive
Ecophyto2018
WRMCountry specifics– Example France
STAKES 1. Re-Positioning the uses of Roundup in sustainable agronomic systems2. Helping our customers to position/justify the uses of Roundup in the
context of chemical restrictions
Water quality
Inter-crops
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
Weed Resistance : Selection pressure
Courtesy of Ian Heap
Resistant
Resistance is detected when a high proportion (usually >15-30%) of the treated population isresistant to the herbicide.
"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.”
Shorten the Learning Curve on Weed Management in the Future
Assume escapes are due to missed applications.
No proactive change to herbicide program. The resistant weeds spread to larger areas of the field.
Begin experimenting with residual products. A complete weed management program is not implemented or the appropriate herbicide was not use.
Understand all the tools that can be used to manage the weeds, and have implemented a systems approach to manage them.
Minor adjustments to rates and timings of herbicides system and management practices.
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
Baseline studies are only needed when the performance of a herbicide in not clearly understood
– glyphosate performance is well known.
Courtesy B. Johnson
Monitoring, reporting and reaction to changes of performance
Grower performance
enquiry
Initial investigation with retailer, Monsanto and grower
Likely performance issue(application, rate & timing, …)
Remedial treatment recommendation from Monsanto
Follow-up to ensure effective control obtained
Confirmation that resistance is not involved
Opportunity to train on Good Agricultural Practices
Implementation of mitigation planPublication and notification to registration
bodiesMonitoring and follow-up in next seasons
Resistance confirmed
Further investigation of the case(green-house efficacy, heritability tests,…)
Field test assuming possible resistance, looking for management for the issue
Possible resistance
Glyphosate Resistance – reported as well as allegations
8
Spain:Lolium rigidumLolium multiflorumConyza bonariensisConyza canadensisConyza sumatriensis
Italy:Lolium rigidumPortugal:
Lolium rigidumConyza bonariensis ??
FranceLolium rigidumConyza sumatriensis ??
GreeceConyza bonariensis
Israel:Lolium rigidumConyza bonariensis
Not on map, CZ republic:Conyza canadiensis (railways)
Resistance Mechanisms are not Equal in Magnitude or Probability
Combinations Possible
Metabolism• Weak Resistance
•ALS, ACCase, •Photosystem 2•DNA•Most others
11/6/2008 9MONSANTO CONFIDENTIAL
Target Site Mutations • Weak to IMMUNE
• ALS, ACCase, •Photosystem 2•DNA
Exclusion• Weak Resistance; Very Rare
•Active (sequestration)•Passive (cuticle )
10
Metabolism• Legumes• Very SLOW
Target SiteMutations
• Pro106X
Over Expression• Copy number• Expression level
Extracellular• Hypersensitive, excission
•Slow acrossplasmalema
Intracellular• Vacuole accumulation ~8X Single gene, Dominant
Exclusion
Combinations Known
Glyphosate Resistance Mechanisms
12
20
2
4
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
“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
Factors associated with glyphosate resistance development
12European cases are only present in perennial and non crop situations.
Arable crops in Europe are not a problem so far.
No alternative controlmethods
Control recommendations example ConyzaOptimum stage for treatment: Rosette StageOr seedling or flowering (at higher rates) but not stem extension
Best with low water volume < 200 lts/haBest results from rosette applications in early springConyza germinates from autumn to spring so mix of growth stages common –low efficacy often not related to resistance
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
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
Per
cent
Con
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…..
Different registration even within the TNV segment Example Italy
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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
Alternating Herbicides vs Mixtures (Postemergence example)
0.34
11
29
0.6
8
Biomass @ maturity (g/m2) Resistant seed bank (%)
Field pennycress (Thlaspiarvense) response averaged over 4 yr of the experiment
No ALS ALS 1:4 ALS Mixture
Selection for Weed Resistance: Herbicide Rotation and Mixture. Beckie et al. Weed Tech. 2009.
Herbicide mixtures, whose components are equally effective against the target weed species, are predicted through model simulations to delay resistance longer than rotations.
Powles et al. 1997; Dingle et al, 2003;Beckie et al. 2009;
0.5 0.75 1 2 4 8 0 lb/a
8C
25C
Resistant Horseweed is sensitivewhen cold acclimated
42 DAT
24 hr
12 hr
2 hr
Resistance mechanism is not ON in the cold
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
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%
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
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
• PRODUCE MORE:
– Double corn, soy, cotton & canola yields by 2030 vs. 2000
• IMPROVE FARMERS’ LIVES:
– By boosting productivity and efficiency, including reaching more than 5M subsistence farmers by 2020
• CONSERVE MORE:
– Reduce aggregate use of key resources by 1/3 per unit of output by 2030 vs. 2000
Monsanto’s Commitment to Sustainable Agriculture
Sustainable Weed Management
Thank you !