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2015 clethodim vs butroxydim webinar-small

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2015 clethodim vs butroxydim webinar-small

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2015 clethodim vs butroxydim webinar-small

  1. 1. Life Impact The University of Adelaide When is it worth rotating from clethodim (eg. Select®) to butroxydim (Factor®)? Peter Boutsalis University of Adelaide & Plant Science Consulting Plant Science Consulting
  2. 2. Life Impact The University of Adelaide Outline • Introduction to Group A herbicides • Mode of action & Target site resistance • Distribution of TS resistance- paddock & regional distribution. • Efficacy of butroxydim and clethodim • Quantifying resistance • Other factors affecting DIM efficacy • IWM of DIM resistant ryegrass eg. in canola Slide 2
  3. 3. Life Impact The University of Adelaide Classifying Group A’s • According to chemical family: FOPs, DIMs, DEN • Classifying Group A’s according to wheat selectivity. • Wheat selective Group A’s – Resistance can be due to metabolic or target site resistance – Hoegrass, Topik, Achieve, Axial etc. • Broadleaf crop selective Group A’s – No metabolism of these herbicides in wheat – Target site resistance – Verdict, Targa, Select, Factor Slide 3
  4. 4. Life Impact The University of Adelaide How do DIMs work • All Group A’s inhibit one enzyme • Acetyl Coenzyme A Carboxylase (ACCase). • All Group A’s bind to one site on ACCase • Binding not identical • Mutations at this binding site cause reduced binding therefore resistance
  5. 5. Target Site Resistance: Variations even occur within a Group-DIMs (between Achieve, Select, Factor) • Herbicides are chemically different and bind to the target in slightly different ways. • Different mutations change the target site in different ways H2 H1 Target enzyme Target enzyme Target enzyme H2 H1 H2 H1
  6. 6. Group A resistance mutations 1781 1999 2027 2041 2078 2088 2096 Biotin carboxylase Biotin carrier Carboxyl transferase ACCase gene 7 mutation sites have been identified. Different sites give rise to different resistance profiles At some sites, there a several mutations possible which often have different resistance profiles Mutations conferring resistance to FOPs more common that DIM mutations
  7. 7. Life Impact The University of Adelaide Mutations causing Group A resistance
  8. 8. Group A DIM-resistance Symptoms range from dead – stunted – healthy plants
  9. 9. Distribution of Group A herbicide resistance in a paddock. Why higher rates of clethodim/ butroxydim can control Group A resistant ryegrass
  10. 10. Distribution of resistance – DNA technology 2078 25 2041 3 2078, 2041 11 2078, 2088 5 2041, 1781 1 1781, 2041, 2078 1 2041, 2078, 2088 1 Paddock 1 Different mutations can occur in a single paddock!!!! Clethodim/ butroxydim unlikely to control plants with double/triple mutations Paddock 2 Paddock 3 ACCase Target site mutations
  11. 11. Random weed surveys between 2003-2013 • Points refer to paddocks sampled
  12. 12. Life Impact The University of Adelaide Example of Random weed survey
  13. 13. Life Impact The University of Adelaide Changes in Group A resistance between 1998 & 2008 in the mid- North, SA Year Target site resistant Non- target site resistant Hoegrass 1000ml/ha Achieve 380g/ha Axial 300ml/ha Select 250ml/ha 2008 89 11 76 64 59 40 2003 83 17 77 45 36 31 1998 76 24 38 nt nt 19 Data is % of resistant paddock samples in a pot test Data is % of Hoegrass resistant samples with 1 or 2 ACCase target site mutations Non-target site resistance: Metabolic, new mechanism or Target site not discovered yet
  14. 14. Mutation 1998 2003 2008 1781 6 8 13 2027 10 7 6 2041 40 32 43 2078 13 13 21 2088 11 6 19 2096 1 1 1781, 1999 1 1781, 2027 1 1781, 2041 3 2 14 1781, 2078 3 3 1781, 2096 2 1999, 2041 1 1999, 2078 3 2027, 2041 2 2 2027, 2078 3 2041, 2078 3 5 4 2041, 2088 1 3 2078, 2088 6 3 2078, 2096 2 2088, 2096 1 Distribution of ACCase mutations in SA 60-70% of R plants from all years had 1 mutation 6%of R plants had two mutations from 1998 survey 22-23% of R plants had two mutations in 2003 & 2008
  15. 15. Life Impact The University of Adelaide Resistance to Clethodim & Butroxydim • Research to date has shown that Clethodim or Butroxydim resistance in ryegrass is due to Group A TARGET SITE resistance. • “But increasing the DIM rate often improves control” Isn’t this classic ‘Metabolic resistance’?? NO • Few cases of ryegrass with Clethodim/ Butroxydim that don’t possess the common TS resistance mutations
  16. 16. Factor vs Select on ryegrass  High rates of Select improve control  Factor can sometimes improve control on Select resistant ryegrass (depends on mutations)  Sometimes Select better than Factor  Factor + Select mixtures- possible synergism.  Some mutations may have fitness penalty
  17. 17. Order of use of Group A herbicides for ryegrass FOPs> Achieve ≥ Axial > Select* ≥ Factor* *rate effect
  18. 18. Select vs Factor in controlling Group A resistant ryegrass- 1 trial Data is Control (%) Growth stage at spraying was 3 leaf stage. Supercharge used with Factor, Hasten used with Select. Biotype Factor 100 Factor 180 Select 300 Select 500 Select 1000 954 75 83 80 100 100 956 66 74 50 80 90 969 19 82 27 70 88 834 91 100 95 100 100 866 93 99 83 100 100 932 95 98 67 96 93 748 78 100 75 100 100 752 74 98 80 100 100 755 64 100 33 98 100 541 7 85 50 100 100 737 22 88 63 91 100 1212.3 40 77 69 56 100 1234.1 60 100 25 78 80 1197.2 55 85 80 100 100 1209.3 76 100 83 98 100 1174.2 21 81 40 98 100 1293 9 17 13 43 67 L300 63 93 75 98 100 L739 10 21 33 32 80 AUS93 68 100 90 100 100 SLR4 100 100 100 100 100 Green= 90-100% control Yellow= 41-89 %control Red= 0-40% control
  19. 19. Select vs Factor in controlling Group A resistant ryegrass- PSC results Data is Control (%) Green= 90-100% control Yellow= 41-89 %control Red= 0-40% control Town State Factor 180 Select 500 WA 90 90 Ardrossan SA 100 90 Kendenup WA 100 85 Naracoorte SA 80 85 Donald VIC 95 80 Corowa NSW 100 80 Horsham VIC 85 80 Esperance WA 65 70 Berrigan NSW 95 70 Horsham VIC 80 70 Corowa NSW 75 65 Williams WA 60 65 Cobram VIC 55 65 Berrigan NSW 100 65 Donald VIC 85 60 Horsham VIC 55 60 Horsham VIC 65 60 Corowa NSW 100 45 Tintinara SA 65 45 Corowa NSW 50 40 Donald VIC 80 40 Narrogin WA 70 40 Cunderdin WA 60 40 Horsham VIC 40 40 Horsham VIC 60 40 WA 30 25 Donald VIC 55 10 Corowa NSW 5 0
  20. 20. What mutations occur in my paddock?  Commercial DNA analysis not available commercially  DNA analysis mainly used to test for presence of known mutations  Multiple mechanisms are responsible for resistance  What information do growers actually require?  Which herbicides work and at what rates!!  Currently only possible with a whole plant resistance test.
  21. 21. Whole plant resistance test Lab tests cannot provide the information in this photo
  22. 22. Select, Factor, Select + Factor 250 500 750 900 11000 Select Factor 80 Select 500 + Factor 80 Factor 180
  23. 23. Ryegrass resistance- Relationship between Group A’s FOPS DEN DIM If resistant to below: Hoegrass Verdict Targa Axial Achieve Select Factor Hoegrass - R R ? ? ? ? Verdict R - R ? ? ? ? Targa R R - ? ? ? ? Axial R R R - R ? ? Achieve R R R R - ? ? Select R R R R R - ? Factor R R R R R R - Rate response: Select, Factor
  24. 24. Results Ratings RRR RR R
  25. 25. Testing methods Quick-Test Seed Test www.plantscienceconsulting.com.au
  26. 26. Life Impact The University of Adelaide Field failures are not always due to resistance. (verify with a test) Getting the most out of DIM herbicides • Spraying younger plants vs waiting to ‘get them all’ • By default, earlier spraying • Younger weeds • warmer conditions • Less chance of frost • Reduced control when ryegrass stressed • Spray before frost vs after frost Slide 28 Improved efficacy
  27. 27. Life Impact The University of Adelaide Effect of cold period/ frost before and after clethodim treatment on ryegrass 1 10 0 20 40 60 80 100 S No Frost S Frost Pre S Frost Post Clethodim (g ha-1 ) Dryweight(%control) 2013 1 10 100 0 20 40 60 80 100 NF FBS FAS Clethodim g ha-1 Survival(%) 2014 Clethodim g ha-1 Survival(%) 1 10 100 0 20 40 60 80 100 NF FBS FAS 2012 Frost or cold period before or after spraying can reduce clethodim efficacy • NF = no frost, • FBS= frost before spray • FAS= frost after spray
  28. 28. Life Impact The University of Adelaide Managing clethodim resistant ryegrass in canola- IWM strategies. • Reduce seedbank to take pressure of DIMs eg. knockdowns, pre-emergent & seed-set control • Seed-set control- manage survivors/ late germinators. • Target young weeds • Warmer temp’s can increase DIM activity • Frost after clethodim application reduces efficacy. • Addition of low rate Factor (80g/ha) may improve clethodim activity • Rotate- glyphosate, TT, CLR • Alternative MOA herbicides
  29. 29. Life Impact The University of Adelaide Conclusion: Final Slide • Resistance testing: know what you’re dealing with • Ongoing research: Clethodim + butroxydim mixes as short-term solution • Multi-pronged approach required for sustainable control of DIM resistant ryegrass.

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