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2015 ballarat crop updates-optimising the impact of glyphosate

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2015 ballarat crop updates-optimising the impact of glyphosate

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2015 ballarat crop updates-optimising the impact of glyphosate

  1. 1. Optimising the impact of glyphosate - Glyphosate resistance - Factors affecting glyphosate performance - Improving glyphosate performance 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. Where & why has glyphosate resistant ryegrass evolved? 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 Intensive use of glyphosate >15yr with little alternative weed control practices
  5. 5. Uni of Adelaide random weed surveys between 2004-2014 (Glyphosate resistance) 16% (2012) 1% (2013)
  6. 6. Facts about glyphosate resistant weeds • All growth stages are resistant- seedlings, pollen etc. • Younger growth stages can be more sensitive. • Resistance transferred by pollen & seed • Progeny from survivors can be more resistant (accumulation of mechanisms)
  7. 7. Increasing the level of glyphosate resistance: mechanisms are additiveSurvival(%) TS S Translocation Cross: Translocation + TS
  8. 8. Reduced glyphosate efficacy – Herbicide resistance (weak or strong) – Depends on type of resistance mechanism • Target-site resistance: weak to strong (not common) • Increased expression of EPSP (brome) • Uptake and translocation/ sequestration (common) – Depends on the nr of resistance mechanisms present in individuals
  9. 9. 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
  10. 10. Reduced glyphosate efficacy • The below factors are not independent of each other: – Treating older/ larger plants – Poor coverage  sub-lethal rate • Nozzles, water rates, calibration – 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  sub-lethal effect
  11. 11. 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 can improve control of HR individuals. – Avoid using higher rates unless a resistance test confirms effective. – 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). – Test for glyphosate resistance (several rates) important.
  12. 12. Quick-Test: Survivors resistant ??
  13. 13. Glyphosate resistance testing • Seed Testing from 2014: – 275 ryegrass samples & 251 Glyphosate testing requests (91%) – Data not available on % resistant samples • Seed Testing from 2013: – 305 ryegrass samples & 232 Glyphosate testing requests (76%) – 71% exhibited glyphosate resistance
  14. 14. 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
  15. 15. Are survivors always Glyphosate resistant? Paraquat mixtures, bromacil 2L/ha Glyphosate
  16. 16. Control of Glyphosate -R ryegrass on a fence line in Kapunda SA with herbicide mixtures- 2013 Fenceline was sprayed in late winter, 2013
  17. 17. Kapunda SA, 2013 At spraying Untreated Uragan 3kg/ha + Basta 5 L/haUragan 3kg/ha + Paraquat 2 L/ha
  18. 18. Life Impact The University of Adelaide
  19. 19. Life Impact The University of Adelaide
  20. 20. Life Impact The University of Adelaide
  21. 21. Life Impact The University of Adelaide
  22. 22. Life Impact The University of Adelaide
  23. 23. Life Impact The University of Adelaide
  24. 24. The End Plant Science Consulting

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