Glyphosate Weed resistance and Weed Resistance Management in Europe Prague , June 2011 Ivo Brants Regulatory Sciences Lead, EMEA
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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.
Presenter
Presentation Notes
Palmer pigweed was found resistant in Georgia in 2005 and over the course of the last 5 years resistant palmer has grown to be the top issue and problem for cotton farmers. It is important that we take the learnings of Palmer in the southern U.S. and apply it to the Corn/Soybean Belt so we can shorten the learning curve in effectively managing glyphosate-resistant weeds. This is a representation of the process growers go through from the first weed escapes to full blown resistance and finally to effective management. When growers first have escapes, they think it is a rate, weather, and/or timing issue and they likely have the same program the following year. Growers in Georgia where resistant Palmer was first identified are in year 5, they are making minor adjustments to their weed management program. Many growers in the Delta region this past year are in year 3 of the above timeline as they used a Reflex or Valor along with Dual or Warrant in-season but likely did not use the complete herbicide program that we offer growers through our Cotton Performance Plus program. What we have to do in all areas when resistance develops is quickly move growers to year 5 and use the complete program for RR Flex cotton or Roundup Ready soybean. In the Midwest our strategy is to move growers from year 1 to Year 4 or 5 quickly by incorporating a residual product either PRE or POST in their Roundup Ready Soybean System.
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 )
Presenter
Presentation Notes
Starting hypothesis is thee are three basic mechanism types
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
Presenter
Presentation Notes
Mechanisms are getting more complicated, need a common system to overcome. Weaker mechanisms are selected by low dose and can accumulate together.
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…..
Presenter
Presentation Notes
Managing Resistance from an Industry perspective means putting resources into research and development. This is not just industry, this includes University/CES, commodity groups, USDA-ARS Will briefly discuss each point: Mechansim: this work is not just to satisfy academic curiosity but to provide clues leading to better management and provide tools to better monitor Weed biology/Modeling: Allows a way to compare best methods to retard development in specific herbicide x species situation Identification of new species and populations: all parties actively monitor performance issues and growers/retailers are acutely aware of resistance…in fact there are many more reports of resistance than there is actual resistance in some cases How would we grade our self in each area…. Are we generating the basic information on mechanism of resistance and weed biology needed to develop best possible solutions? Are we putting enough resources into field studies where we will be able to directly compare approaches to retards the evolution of resistance? As scientist, our answer is NO to these question but since resources are not unlimited this becomes an an issue of prioritization and finding ways to be most efficient in generating the needed data . Regarding needing to be more efficient, we are seeing an increase in cross regional and beyond regional industry/university collaborations, between Universities is increasing. Just look at our publications and you see papers with authors from more than one university (example of recent publication with 18 authors across 6 universities and the company sponsor).
Different registration even within the TNV segment Example Italy
16
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
Presenter
Presentation Notes
The photo of the first comparison of cold and warm growing conditions showing that glyphosate resistant horseweed is controlled by the labeled field use rate when cold acclimated. Supported by NMR
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
Presenter
Presentation Notes
When we talk about best practices, there are several aspects to think about. One aspect is related to general guidelines /practices intended to retard development of resistance. And the other are guidelines to manage an existing problem HRAC has published the guidelines seen here on the Global HRAC website. These guidelines are built around a few key concepts; (1) need for diversity of weed control, (2) early detection / early warning and (3) retarding spread of the resistant gene(s) and from what I have seen these very much the same messages coming from the universities and others. I show this to present the opinion that significant progress has been made in delivering a consistent message to farmers regarding best practices to retard the evolution of resistance. However, we are all not perfectly aligned but again I don’t think many would argue that progress has been significant from say 5 years ago. (Now there are more differences is what are the best ways to manage existing problems due to regional differences as related to different cropping situations and competition between companies also comes into play) One other point I would make is that… As we learn more about mode of resistance, weed biology, etc. I think it is becoming clearer that one approach may not be found to be the best in all product x weed x cropping situation. Again from the standpoint of retarding the evolution of resistance.
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
Presenter
Presentation Notes
Progress is being made and there is evidence that the efforts to educate farmers and retailers on the perils of resistance and ways to mitigate resistance are paying off…farmers are listening. And more can be done Groups (Industry and University/CES) and individual states are looking for new ways to reach farmers/retailers and developing new tools to help farmers. What I have listed here are just a few examples of recent initiatives.
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
Presenter
Presentation Notes
Sustainable agriculture is what Monsanto is all about. We deliver tools that farmers can choose to produce more, conserve more and improve lives. In the summer of 2008, we set three ambitious but achievable goals. We said we’d like farmers to be able to double yields in corn, soybeans, cotton and canola between 2000 and 2030 … and to do it while using one-third fewer key resources, such as water and energy, for every bushel and bale they produce. And that when they succeed on those two fronts, they’ll improve lives – their own, their families’ and their communities’ … from rural villages in Africa and India, to high-tech farming operations in the U.S. and Brazil. Our part is to provide them with seeds and other tools to make that happen. Some of this work occurs through our day-to-day operations – by selling our products to farmers in established commercial markets. Some occurs through public-private partnerships focused on preserving the environment, on building markets, and on enabling farmers in the developing world.
Thank you !