How resistant is Northern Europe?
FredericiaAugust 18, 2011Hans G. Drobny
Resistance in Northern/Central Europe
• What is resistance?• How is it organized?• Status of resistance• How to select and to establish
resistance?• Some rules• Outlook
What is Resistance?
The naturally occuring, inheritable ability of individual biotypes within a pest population, to survive pesticide treatments which under normal circumstances would control these populations
This ability is genetically based (mutation), will be selected by the respective pesticide, and is passed onto the next generation
Characteristics of metabolic and target-site resistance
Target-siteTarget enzym mutation / binding
Qualitative (practical): yes/no
Mode of action
Resistant individuals practically completely resistant
Weeds: “nests” in field
Fitness good
Other MoA works
dominant heredity
Metabolicincreased metabolic activity
Quantitative: decreasing efficacy
chemical structure/ mechanism of degradation
Varying degrees of resistance
Gradual shift of whole populations
Fitness good
Other MoA molecules can be affected the same time
Resistance: further definitions• Cross resistance:
– A single mutation results in resistance against several a.i.‘s, mostly from the same MoA group
• Multiple Resistance– 2 or more mutations or mechanisms result in
resistance against same/different a.i.‘s or MoA groups
• Target-Site Mutations– Different locations of mutations on the enzym
can result in resistance (mostly „typical“ locations on each enzym)
– Subgroups of MoA groups can be affected in different ways: FOP/DIM, SU/TAP/IMI, strob‘s F129L
ALS Target Site Mutations
The ALS enzyme show its major mutations on the following amino acids: ALA 122, PRO 197, ALA 205, TRP 574, SER 653
Resistance to sulfonylurea and triazolopyrimidine Proline 197 to Ile, Ala, His - Raphanus
Resistance to imidazolinoneAlanine 122 to Thr - XanthiumSer 653 to Thr - Amaranthus spp.
Resistance to sulfonylureas Proline 197 to Arg,Gln,Ser - Kochia, Papaver
Resistance to all ALS InhibitorsProline 197 to Leu - Amaranthus spp.Alanine 205 to Val - Xanthium
Resistance to SU + IMI + TPTrp 574 to Leu - Sisymbrium, Ambrosia
Metabolic Resistance ALOMYschematic illustration of its development (UK, D)
P450 Potenz
0 6-8 8-12 today years
% individuals/ population
metsulfurontribenuron thifensulfuron amidosulfuron
Ureas .
FOP‘s
9 g/ha mesosulfuron .
mesosulfuron 15 g/ha .
.flurpyrsulfuronpropoxycarbazone
HRAC guide line metabolic resistance
• In cases where metabolic resistance is already present, the mode of action of the herbicide is not always the key criterion. In these cases, the mechanism of degradation can be very important and cross mode of action groups and chemistries. No classification of herbicides relating to degradation is available and such examples need to be handled on a case by case basis.
Who cares about resistance?• Industry
– RAC‘s: Resistance Action Committee – HRAC, IRAC, FRAC
• Registration authorities– Notification and precautionary
statements– Action Groups („RAG‘s“): NORBARAG
• Official and private advisors• Competition….Resistance is „sexy“!
How is resistance organized?• RAC‘s: Resistance Action
Committees– Industry representatives, global scope– HRAC, FRAC, IRAC– Public / Internet– Specialized working groups– Classification of a.i.‘s into „mode of action“
groups, and cross resistance– Guidelines for preventing/managing
resistant populations– Development of test methods– Establishment base lines
How is resistance organized -2?• RAG‘s: Resistance Action Groups
– Regulatory bodies, official advisors, industry– NORBARAG: Nordic and Baltic states– Germany: Fachausschuss PSM-Resistenz (3)– Austria: AGES „Runder Tisch Resistenz“– Monitoring resistant populations in territory– Guidelines for preventing/managing
resistant populations under local conditions– Label statements– Interface with the RAC‘s
NORBARAG Objectives• to provide a forum for information exchange
between people actively involved in research into pesticide resistance and efficacy evaluation of pesticides
• to ensure that cases of resistance in the Nordic-Baltic region is verified and listed
• to discuss strategies to avoid resistance and to manage resistant populations
• to define research needs, discuss test methodologies and agree on standards
• to promote collaboration on resistance screening and other research topics related to pesticide resistance
• to promote awareness on pesticide resistance issues e.g. by producing educational material
• to maintain contacts to similar groups in other countries
Activities of German RAG‘s
– Reports/sharing of new findings/results• Partly joint monitoring programs
– Connection to RAC‘s – local implementation– Recommendations for practical
management under German/local conditions• Crops and crop rotations• Pests• Available tools
– Fact finding for special approvals of products to manage resistance issues
– External communication via Internet
Carbamate
Oxadiazine
Diamide
Pyrethroide
Neonicotinoide
OP-Ester
Metamorphosehemmer
Häutungsbeschleuniger
Example monitoring:Blumeria graminis/proquinazid
Routine monitoring since 2006Characterisation of less sensitive isolates with full dose responseCross-resistance with metrafenone and cyflufenamid
480 airborne isolates collected in 6 European countries Study carried out by EpiLogic Regular reporting/discussion of results at FRAC working group “Azanaphthalenes” Presentation at German FRAG group
(a) pooter(b) roller mixer(c) glass tube
a
b c
Example: Methodology development for monitoring M. aeneusadults susceptibility to indoxacarb
These are the proper glass vials used for 2008 – 2009 bioassays
BTLVial test
International survey resistant weeds
Example: Evaluation Methods at the whole plant level• Greenhouse test on pots :
Characterization of Herbicide resistant Weeds
Harvest Seeds or Plants Planting seeds or transplanting plants
Greenhouse set up
Treatment
Growth and Evaluation
Plants at 3 leaves GS
From seeds 15 days are needto reach stage 2-3leaves
Evaluation at 21 DAT
Control Resistant Susceptible
Example: Results molecular genetic analysis
Mutated Allel Position 197 in bold.Mutation CCA zu ACA oder ACC : Prolin to Threonin.
Example: Resistance factor Comparison dose-response curves of sensitive reference population
(MRS) and the suspect sample (SH 1)
Resistance factor calculated from ED50-values: RF = 59,6
Relevant Weed Resistance Issues Northern Europe
• Triazin-resistant Weeds– New: Chenopodium against Metamitron
• ALOMY– Quantitative metabolic resistance against different a.i.‘s:
ureas, FOP‘s (not DIM‘s!), SU‘s, inh. of cell division– ACCase target site resistance (FOP‘s/DEN and DIM‘s)– ALS target site resistance– multiple resistances: metabolic combined with ACCase-
and ALS-target-site resistance• APESV
– Quantitative resistance against IPU and ALS-Inh.– Target-site resistance against ALS-Inh. and ACCAse-Inh.
(?)• STEME, PAPRH, MATCH, MATIN, SONAR,
CHYSE,…– Target-site resistance against ALS-Inh.– Nordic and UK; Germany: only MATSPX
Relevant Fungicide Resistance Cases Germany and Northern Europe
• Strobilurines (QoI‘s)– Target-site resistance Septoria tritici, Powdery Mildew
wheat, Erysiphe necator (grapes), Pyrenophora teres (F129L)
– NORDIC: S.tritici, M.nivale, DTR, Ramularia, P.teres• Triazoles
– „Shifting“ with several cereal diseases;– NORDIC: Septoria tritici
• Phenylamides – Downy mildew grapes and potatoes
• The „Resistance Trio“: Botrytis, Scab, Mildew– Recent reports on metrafenone/cereals/Blumeria graminis
• Special laboratory used by most organisations: Epilogic
Relevant Insecticide Resistance Cases Germany and Northern Europe
• Pyrethroides– Meligethes– Other rape pests: Ceutorhynchus, Psylloides– Colorado Potatoe Beetle– Aphids
• Carbamates and OP-Esters– Several sucking and chewing insects– Only few actives remaining
• Neonicotinoides– First reports aphids (Phorodon humili) and White flies– increasing market shares/strong exposure (start seed dressing)– X-resistant to pymetrozyn (different chemistry, IRAC group 9)– Not X-resistant to flonicamid (similar chemistry, IRAC group 9)
• Some crops with only pyrethroids (widespread resistance) and neonics: Rape, potatoes, beets
How come resistant populations?
• Naturally occurring mutations– The more individuals there are, the higher is the probability
of mutated individuals/field PLUS
• Selection of these mutants via a specific selection agent– Pesticides are powerful and mostly specific selection agents – Continuous application of the same selection agent leads to
propagation of the mutated individuals to a population • Worst case example:
– Provide optimum conditions for growth and propagation of a weed via cultural practices
PLUS– Continuous application of the same MoA herbicides– Blackgrass in the Northern German marsh areas
General Risk Faktors• Changes in agronomic pratices: favour specific
weeds – Narrow crop rotations– No-till systems
• Little (chemical) Renewal– Cost rel. to market potential
• Glyphosate/Glufosinate tolerant crops– High entry barriers (f.e. SU‘s)
• Regulatory authorities favour potentially „higher risk“ MoA classes– One-site Inhibitors (no/little side effects)– Metabolically instable (fast degradation environment)
• Cancellations/limitations „robust“ (multi-site) a.i.‘s– IPU, Trifluralin, …
• Revision 91/414/EEC into EU 1107/2009 – RAC‘s and RAG‘s do lobbying work to include/consider
resistance
Task: establishment of a resistant weed population
1. Generate high population density of target weed1. - crop rotation: only winter or summer crops,
• Best for grasses: only wi-cereals
2. - reduced/one-sided agricultural means: • No plough, very early seeding times
3. - allow/accept imperfect efficacy: many new seeds
2. One-sided application of herbicides1. - 1 mode-of-action solo2. - only post-em spring3. - no change (MoA) in the whole crop rotation4. - no mechanical or other field hygene
3. Protract seeds from affected fields to other fields
Task: establishment of a resistant weed population– it works!
• Blackgrass (ALOMY) in England– Wi-cereals, mono culture, no plough for many years– IPU/CTU (m), FOP‘s (m), DIM+FOP (t-s), Lexus®/Attribut (m und t-s), „soil
herbicides“ (m?), Atlantis (m und t-s)– Marsh areas in Schleswig-Holstein follow closely…
• Several weed species Norway– Spring cereal mono culture– Almost exclusive use of ALS-inhibitors for many years: populations of several
weed species with ALS t-s resistance : MATIN, PAPRH, STEME, SPEAR…– Other MoA groups with higher taxes– Denmark: winter and spring cereals, mixtures different MoA common: much
less problems• APESV in Sweden
– Winter cereals mono culture– Only product registered for several years: Ralon (fenoxaprop-e)– ACCase target-site (and metabolic) resistance
• APESV in Poland und CZ– WWheat mono culture– 25 years application ALS-Hemmers solo (Glean®) in autumn– Last 10 years specific ALS-inhibitors post-em spring: resistance against ALS-
inh. – last 3-5 years application FOP‘s: resistance against fenoxaprop-e (and
others?)
ALS Target Site Mutation: Stellaria media case
Resistance to ALS Inhibitor Herbicides
PopulationRef A B C D E F
metsulfuron-methyl S R R R R R Rsulfosulfuron S R R R R R R
tribenuron-methyl S R R R R R Rflupyrsulfuron-methyl S R R R R R R
florasulam S S S R R R Sfluroxypyr S S S S S S Sbentazone S S S S S S S
Years Crops Herbicide Treatments1985 Spring Barley Chlorsulfuron + HBN1986 Spring Barley Chlorsulfuron + HBN1987 Spring Barley Metsulfuron-methyl + MCPP1988 Spring Barley Metsulfuron-methyl + MCPP1989 Spring Barley Metsulfuron-methyl + MCPP1990 Spring Barley Metsulfuron-methyl + MCPP1991 Spring Barley Metsulfuron-methyl + MCPP1992 Spring Barley Metsulfuron-methyl + MCPP1993 Spring Barley Metsulfuron-methyl + MCPP1994 Spring Barley Metsulfuron-methyl + MCPP1995 Spring Barley Metsulfuron-methyl1996 Spring Barley Metsulfuron-methyl Confirmed resistance
Two important characteristics for the development of herbicide resistance were puttogether in this field : crop monoculture and use of the same herbicide (9 years ofsulf onylurea treatments (chlorsulfuron and metsulfuron-methyl)).
Cross resistant profile
Resistance ALOMY – practical findings LWA (agricultural office) Ilshofen (G.Federolf)
• Resistance against IPU: since 1993
• against Ralon S (fenoxaprop-e): 1998
• against Atlantis (mesosulfuron+iodosulfuron): 2005
• against FOP‘s (not selective in cereala): 2002
• against DIM‘s: 2007
Black Grass Management• If possible, remove occasional black-grass plants
before seeds shed, or spray off patches in June.• Avoid spreading seeds to new fields in combines,
cultivators or in straw• Place more emphasis on cultural control measures
(ploughing, crop rotation, spring cropping, delayed autumn drilling, higher cereal seed rates)
• Don’t rely solely on ‘high risk’ chemistry e.g. ‘fop’/‘dims’ (e.g. fenoxaprop) or sulfonylurea herbicides (e.g ‘Atlantis’)
• Remember that mixtures and sequences will slow, but not stop resistance development
• If resistance is suspected, have a seed or plant sample tested
Stephen Moss, Rothamsted, 2009
Risk evaluation Herbicides
Relatively broad spectrum of MoA classes available
Not in NordicNo new MoA classes in sight
Problems can be managed at individual field level
GMO political tabu
Epidemiology „controlled“:Rel. few individuals/ha+/- localized
„Ideal“ MoA classes have higher risk : ALS-Inh., ACCase-Inh.
Changes in agronomic practices can lead to favour specific weed species
positive negative
What can I do?to prevent and manage problems….
Weeds – manage by field!• Make sure no single species becomes
predominant in the crop rotation– Agronomic practices: soil tillage, seeding date, rotation– Effective use of herbicides in each season/crop
• When critical weed species becomes established– Check/change crop rotation, practices– Aim to reach levels of control as high as possible:
mixtures, sequences of herbicides; additives, optimum timing
– Intelligent rotation of a.i.‘s/MoA groups between the rotational crops
– Integrate low(er) risk MoA: „soil herbicides“ in wi-cereals, rape seed, sugar beets,…
What can I do?when chemistry is vanishing….
Diseases and pests• Hinder the outbreak of epidemics
– Crop rotation, agricultural means– Crop varieties (resistance genes)– application of fungicides/insecticides under optimal conditions ( prognosis
models, f.e. ProPlant)• Preserve available actives as much as possible
– Aim for high efficacy: use rate, additives, weather– Alternate or mix different MoA actives (include multi-site inhibitors) and
activity patterns (contact, systemic) in spray programs– Specific integration of alternative MoA products in critical (= at risk for
resistance) segments: Pyrethroides and Neonicotinoides against Pollen Beetle and Potatoe Beetle; Apple Codling Moth
News from the Chemical Industry?• Fungicides
– Several Carboxamides (Succinat-Dehydrogenase-Inh.) for horticultural and arable crops: Boscalid, Penthiopyrad (Vertisan®), Bixafen, Isopyrazam,…
– Several novel a.i.‘s against powdery and downy mildews
• Insecticides– Ryanodin-Receptor-Agonists: Diamides (IRAC Group 28)
• RYNAXYPYR®, CYAZYPYR®– ACCase-Inh.: Ketoenoles (IRAC Group 23)
• Spirotetramat
• Herbicides– Nothing new (MoA classes)– GlyphosateGlyphosate/Glufosinate (in respective GMO crops)– Multiple Tolerances: Glyphosate+ALS, +Dicamba
(GMO)
Chemical renewal selective herbicides?
• Only 2 novel MoA-classes since 1980:– ALS-inhibitors, 4-HPPD-inhibitors (triketones)– Limited market potential due to crop selectivity– Disappearance whole segments: Maize, Soya
• But the related alternative (Glyphosat tolerance) not available in Nordic/EU
– The bar is set very high by the SU‘s!• New actives from existing MoA-classes
mostly affected by both resistance mechanisms– Pyroxulam, Pinoxaden
• Registerability in EU?– Saflufenacil, Aminocyclopyrachlor, Aminopyralid
• No novel herbicidal MoA classes in sight until 2020, in the EU
ALS-inhibitors - outlook• Relevance will increase further
– Mid-term no new herbicidal groups available– New ALS-inh. enter same and new segments– Restrictions/withdrawel old herbicides (non-ALS)– Increase in generic product offerings
• Crops with modified ALS– „conventional“ breeding
• „Clearfield“: Tolerance against Imidazolinones (imazamox)
• ExpressSun®: sunflowers tolerant against Tribenuron
– GMO-crops• OptimumGAT® Stack: Glyphosate+ALS tolerance
Outlook and wishes• Consider resistance management issues when
implementing EU 1107/2009 (revision of 91/414/EEC)
• End of the GMO tabu („Eco-imperialism“)
• Fast, reliable registration and approvals of alternative actives
• Effective coordination of monitoring programs
• Effective communication and implementation of preventative programs– Who is ready/prepared to preventatively invest more
money/work?
• Plant breeding?
• Consider resistance management issues when implementing EU 1107/2009 (revision of 91/414/EEC)
• End of the GMO tabu („Eco-imperialism“)
• Fast, reliable registration and approvals of alternative actives
• Effective coordination of monitoring programs
• Effective communication and implementation of preventative programs– Who is ready/prepared to preventatively invest more
money/work?
• Plant breeding?
Thank you for your attention
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