What to expect from plant growth regulators

This seminar was held at Manila Southwoods Golf and Country Club at a seminar organized by Nutranta Inc.

I explained what to expect from the use of plant growth regulators in the Philippines, specifically related to effects on plant health, turf quality, and resource requirements. I close by discussing application timing.

Transcript

1. What to expect from plant growth regulators
   Micah Woods
   November 20, 2018
   Chief Scientist
   Asian Turfgrass Center
   www.asianturfgrass.com
   

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2. What has the potential to occur?
   from “Insecticides, fungicides, herbicides, and growth regulators used in turfgrass
   systems,” Reicher et al., 2013
   • improve heat stress tolerance
   • improve performance in shade
   • increase green speed
   • decrease sod heating
   • improve density and color
   • increase drought and heat tolerance
   • delay fall dormancy of warm-season grasses
   • hasten spring green-up
   

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3. What has the potential to occur?
   • improve heat stress tolerance
   • improve performance in shade
   • increase green speed
   • decrease sod heating
   • improve density and color
   • increase drought and heat tolerance
   • delay fall dormancy of warm-season grasses
   • hasten spring green-up
   • reduced mowing requirement
   • reduced nutrient requirement
   • reduced water requirement
   

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4. from Reicher et al., 2013
   

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5. Today’s outline
   1. Healthier plants
   2. Better playing conditions
   3. Lower resource use
   4. Optimal application scheduling
   

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6. 1. Healthier plants
   

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7. Manila Golf Club
   

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8. Manila Golf Club, February 2013
   

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9. Manila Golf Club, February 2013
   

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14. • slower growing
    • improved stress tolerance
    • improved shade tolerance
    • more efficient photosynthesis
    

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16. Table 1 from Grime, 1977
    

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17. 2. Better playing conditions
    

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18. More plant density
    manilagrass at Keya GC, Japan
    

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19. Tolerance to lower mowing
    manilagrass at Keya GC, Japan
    

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20. Improved performance in shade
    manilagrass at Keya GC, Japan
    

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21. Possible root enhancement
    manilagrass at Keya GC, Japan
    

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22. 3. Lower resource use
    

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23. The growth rate is slower, so there can be …
    less mowing
    Peak clipping yield suppression at label rates is about 50% of untreated. Mowing
    frequency reduction may be possible.
    

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24. The growth rate is slower, so there can be …
    lower CO
    2
    emissions
    Mowing fairways on an average 18 holes produces about 92 kg of CO
    2
    . With 150
    fairway mows a year, that’s almost 14 tons of CO
    2
    .
    

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25. The growth rate is slower, so there can be …
    lower irrigation water use
    

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27. “by using a surfactant, a PGR, or both, bermudagrass
    quality can be maintained with 15 to 30% less irrigation
    water …without a reduction in color or quality.”
    Serena et al., 2018
    

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28. 4. Optimal application scheduling
    

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29. How much growth reduction?
    “Peak suppression values after a [trinexapac-ethyl] application at 0.034
    kg a.i. ha-1 [280 mL/ha] in this study ranged from 49 to 62%”
    Reasor et al., 2018
    

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31. When does the growth reduction happen?
    “Peak suppression occurred between 166 and 177 GDD calculated using
    10°C as the base temperature (GDD10C
    )”
    Reasor et al., 2018
    

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32. Figure 1 in Reasor et al., 2018
    

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33. from Figure 1 in Reasor et al., 2018
    

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36. Recommended reapplication interval
    Based on the suppression of ultradwarf bermudagrass, Reasor et al. suggest a
    reapplication interval of 216 to 230 accumulated GDD10C
    .
    In days, with Manila weather,
    that works out to reapplication every 12 days on average to maintain consistent
    growth regulation.
    

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37. https://greenkeeperapp.com
    

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43. https://greenkeeperapp.com
    

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44. Minimal use recommendation
    • 3 applications prior to tournament
    • first app 33 days before tournament
    • second app 21 days before tournament
    • final app 9 days before tournament
    

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45. For more, please see www.asianturfgrass.com.
    

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