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2016 webinar-optimising the impact of glyphosate

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How to optimise glyphosate and the latest on herbicide resistance

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2016 webinar-optimising the impact of glyphosate

  1. 1. Understanding glyphosate resistance in ryegrass Plant Science Consulting
  2. 2. Glyphosate resistance W in te r w e e d s Y e a r Numberofpopulations 1 9 9 6 2 0 0 0 2 0 0 4 2 0 0 8 2 0 1 2 0 1 0 0 2 0 0 3 0 0 4 0 0 5 0 0 6 0 0 A n n u al ryeg rass W ild rad ish R e d b ro m e G re a t b ro m e S u m m e r w e e d s Y e a r Numberofpopulations 2 0 0 6 2 0 0 8 2 0 1 0 2 0 1 2 2 0 1 4 0 2 0 4 0 6 0 8 0 1 0 0 B arn y ard g ra ss L iv e rs e e d g ra s s F le a b a n e W in d m ill g rass S o w th is tle 1996-2014 2007-2014
  3. 3. Confirmed cases in Australia
  4. 4. Situation Number of sites States Broadacre cropping Chemical fallow 32 NSW Winter grains Summer grains Irrigated crops 295 1 1 Vic, SA, WA, NSW NSW SA Horticulture Tree crops 10 NSW, SA Vine crops Vegetables 25 2 SA, WA Vic Other Driveway 5 NSW, Vic, SA, WA Fence line /Crop margin Around buildings 89 2 NSW, SA, Vic, WA NSW Irrigation channel /Drain 14 NSW, SA, Vic Airstrip 1 SA Railway 2 WA, NSW Roadside 95 SA, NSW, WA Where & why has glyphosate resistant ryegrass evolved? Intensive use of glyphosate >15yr with little alternative weed control practices
  5. 5. Points indicate fields surveyed by the University of Adelaide GRDC funded random weed surveys. Incidence of Glyphosate resistant fields in red 16% (2012) 1% (2013) 3% (2015) 9% (2015) 1% (2014) 4% (2014) 0% (2012)
  6. 6. 2015 random weed survey- Wimmera Incidence of glyphosate resistance=9%
  7. 7. Facts about glyphosate resistant weeds • All growth stages are resistant- seedlings, pollen etc. • Younger growth stages usually more sensitive. • Resistance transferred by pollen & seed • Progeny from survivors usually more resistant (accumulation of mechanisms) • From fencelines glyphosate resistance detected out to at least 50m • Some glyphosate-resistant populations have reduced fitness (less competitive than susceptible ryegrass in the absence of glyphosate). Produce less seed.
  8. 8. Increasing the level of glyphosate resistance: mechanisms are additiveSurvival(%) TS S Translocation Cross: Translocation + TS
  9. 9. Reduced glyphosate efficacy 1. Herbicide resistance (weak or strong) – Depends on type of resistance mechanism 1. Translocation/ sequestration (to leaf tips)- ryegrass 2. Target-site resistance: weak R detected in ryegrass – Pro106 (S) to Ser/Thr at target site (EPSPS gene) 3. Both 1 & 2 in ryegrass 4. Increased expression of EPSP (brome) (Amaranthus spp in USA (waterhemp, palmer amaranth)
  10. 10. Reduced glyphosate efficacy 2. Other factors: – Treating older/ larger plants eg. fencelines in spring!! – Poor coverage  sub-lethal rate • Nozzles, water rates, calibration, correct boom height – Stressed plants • temperature extremes, moisture, nutrition, pest damage etc. affect translocation etc. • Reduced efficacy at high temperatures (better effect spraying high 20oC’s than 30oC’s) – Dust covering leaves  reduced effect
  11. 11. 2016 Quick-Test Glyphosate resistance results • Received April-June, 2016 • 20 ryegrass plant samples from knockdowns for Glyphosate testing • 14 = not resistant • 6 = resistant
  12. 12. Percent survival (%) of a selection of grower resistance tests from 2013 and 2014 treated with Glyphosate (540g ai/L). Data ranked according to percent survival at 1000ml/ha.  Different resistance profiles! Data courtesy of P. Boutsalis, Plant Science Consulting
  13. 13. Improving glyphosate efficacy – Increased glyphosate rates can aid in buffering the effect of: • Treating older plants • stressed plants • high temperatures • Poor coverage • Dust covering leaves – Increased glyphosate rates sometimes improve control of resistant individuals. – Test for glyphosate resistance (several rates) to determine resistance level (Quick-Test or Seed test). – Do not let glyphosate resistant individuals set seed to avoid accumulation of resistance mechanisms. – Rotate from glyphosate even if no resistance (paraquat products/ residuals eg. bromacil along fencelines/ non-cropped areas).
  14. 14. Elmore Vic Some 2016 farmer results from 2016 Quick-Tests from Victoria
  15. 15. Lake Bolac , Vic Some 2016 farmer results from 2016 Quick-Tests from Victoria
  16. 16. Some 2016 farmer results from 2016 Quick-Tests from SA Bordertown, SA
  17. 17. Some 2016 farmer results from 2016 Quick-Tests from SA Cummins, SA
  18. 18. Some 2016 farmer results from 2016 Quick-Tests from WA Mukinbudin, WA
  19. 19. Some 2016 farmer results from 2016 Quick-Tests from WA Esperance, WA
  20. 20. Glyphosate resistance in ryegrass. Results from 2015 Plant Science Consulting Quick-Test and Seed testing of farmer samples Glyphosate 540 rate (L/ha) Ryegrass Samples Tested % resistant 1.0 200 29 1.5 300 25 2.0 100 15 3.0 125 10  Increasing rates can improve control of plants resistant to lower rates.
  21. 21. Increasing the level of glyphosate resistance: mechanisms are additiveSurvival(%) TS S Translocation Cross: Translocation + TS
  22. 22. Plant Science Consulting 1000ml/ha 1500ml/ha Glyphosate 540g ai/L 1000ml/ha 1500ml/ha Survivors to 1000ml/ha indicates low-level glyphosate resistance which is becoming common
  23. 23. Slight increase in control from 1L to 3L glyphosate
  24. 24. Weak and strong glyphosate survivor from same paddock
  25. 25. Weak glyphosate survivor
  26. 26. Crop Margins- Fenceline control? Paraquat mixtures, bromacil (Uragan) 2L/ha Glyphosate Use residuals along fencelines early in the season starting from pre-sowing
  27. 27. Control of Glyphosate -R ryegrass on a fence line in Kapunda SA with herbicide mixtures- 2013 Fenceline was sprayed in late winter, 2013 Rather than treating fencelines (large plants) in spring: - Use knockdown+residuals before sowing starts or once sowing finished - Sow as close as possible to fenceline with crop-residuals crop competition along fenceline = fewer ryegrass seeds - When sowing outer laps, use outer nozzle to apply residuals along fenceline. - Mowing is used in some cases
  28. 28. Life Impact The University of Adelaide
  29. 29. Life Impact The University of Adelaide
  30. 30. Life Impact The University of Adelaide
  31. 31. www.plantscienceconsulting.com.au PLANT SCIENCE CONSULTING RESISTANCE TESTING
  32. 32. Testing: www.plantscienceconsulting.com.au Testing Plants Testing Seed - Even plants with 50+ tillers can be tested!! - May be interested in a couple of survivors only, eg 5 plants.
  33. 33. Results using Seed Testing Herbicide Product Rate Herbicide Group Farmer paddock (g or ml/ha) Survival (%) Rating Verdict + 1% Hasten 85 A-FOP 70 RR Select + 1% Hasten 250 A-DIM 20 R Select + 1% Hasten 500 A-DIM 0 S Hussar + 1% Hasten 200 B-SU 90 RRR Glyphosate 540 1500 M 0 S Triflur X 1000 D 0 S
  34. 34. The End Plant Science Consulting

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