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Glyphosate Weed resistance andWeed Resistance Management in Europe Prague , June 2011 Ivo Brants Regulatory Sciences Lead, EMEA
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 STAKES1. 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
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 2XHerbicide 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"Herbicide resistance is the inherited ability of a plant to survive and reproducefollowing 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
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 managementAssume The approach to program is notescapes are resistant manage implementeddue to missed weeds or the them.applications. spread to appropriate larger areas herbicide was of the field. not use.
Weed Resistance Monitoring:Objectives: Early detection of new species and spread to new areasOptions: – 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-outsWhat has not worked: – Long-term field studies nor routine monitoring of grower fields are effective for either objectiveWhat 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. JohnsonBaseline studies are only needed when theperformance of a herbicide in not clearly understood – glyphosate performance is well known.
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 resistanceRemedial 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
Glyphosate Resistance – reported as well as allegations Not on map, CZ republic: Conyza canadiensis (railways)FranceLolium rigidumConyza sumatriensis ?? Italy: Spain: GreecePortugal: Lolium rigidum Lolium rigidum Conyza bonariensisLolium rigidum Lolium multiflorumConyza bonariensis ?? Conyza bonariensis Conyza canadensis Israel: Conyza sumatriensis Lolium rigidum Conyza bonariensis 8
Resistance Mechanisms are not Equal in Magnitude or ProbabilityTarget 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
Glyphosate Resistance Mechanisms ExclusionTarget Site Extracellular • Hypersensitive, excission Mutations • Pro106X 1 4 •Slow across 2 plasmalema 2 2Over Expression 0 • Copy number Intracellular • Expression level • Vacuole accumulation Metabolism ~8X Single gene, Dominant • Legumes • Very SLOW Combinations Known 10
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
Factors associated with glyphosate resistance development No alternative control methodsEuropean cases are only present in perennial and non crop situations. Arable crops in Europe are not a problem so far. 12
Control recommendations example ConyzaOptimum stage for treatment: Rosette StageOr seedling or flowering (at higher rates) but not stem extensionBest 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 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 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…..
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
Alternating Herbicides vs Mixtures (Postemergence example)Herbicide mixtures, whose Field pennycress (Thlaspicomponents are equally arvense) response averagedeffective against the target over 4 yr of the experimentweed species, are predicted No ALS ALS 1:4 ALS Mixturethrough model simulations to 29delay resistance longer thanrotations. 11 8Powles et al. 1997; 0.3 0.6 4Dingle 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.
8CResistantHorseweedis sensitive 24 hrwhen cold 0.5 0.75 1 2 4 8acclimated 0 lb/a 25C 12 hr 2 hrResistance mechanism is not ON in the cold 42 DAT
Stewardship GuidelinesGeneral 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. 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
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
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