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Plant growth


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Plant growth

  1. 1. 4/26/2012Plant Growth Regulators (PGR’S)Why: • Reduce growth • Reduction in labor costs • reduced mowing • reduced clippings • Reduce growth when overseeding • Chemical edging around trees etc • Hillsides • Some PGR’s suppress poa seed head 1
  2. 2. 4/26/2012Why PGR’s Continued: • Improve the health of the plant • Density • Drought stress-less water use • Color • Root development • Increase putting green speed • Increases in shade tolerance • Increase wear tolerance What are PGR’s?Original classificationType I and Type II growth regulators: Type I • Compounds foliar absorbed and inhibit cell division at the meristem • Excellent seedhead control 2
  3. 3. 4/26/2012What are PGR’s continued?Type II • Crown or root absorbed • Inhibit or suppress both growth and development • Suppression due to inhibition of gibberallic acid • Usually less phytotoxic • No effect on seedhead formation just elongation of seed stalkNew Classification PGR’s- All reduce growth -Class A:• Late gibberellic acid (GA) synthesis blockers(giberellic acids hormones responsible forcell elongation)• Example Primo Max® (trinexapec-ethyl) • Foliar absorbed • Last 3-6 weeks depending on rate and useClass A continued:USE - poa reduction - Color enhancement - Overseeding reduction in competitiveness of existing species. • germination and development of new seed is normal because of: * late gibberellin synthesis inhibition * class A are foliar absorbed - Increases in shade tolerance 3
  4. 4. 4/26/2012Class B:• Early GA synthesis blocker• Trimmit® (paclobutrazol), Cutless®(flurprimidol)• Root absorbed• Use- poa reductionClass C: • Mitotic inhibitors • Slo Gro® (maleic hydrazide), Embark® (mefluidide), Limit® (amidochlor) • Foliar or root absorbed • Use- poa seedhead suppression • May need to add fungicide, nitrogen, or ironClass D: • Herbicidal mode • Oust® (sulometuron-methyl), Round-up® (glyphosate), Telar® (chlorosulfuron), Prograss® (ethofumestate) • Foliar and/or root • Phytotoxic growth regulating response at low rates/herbicide at high rates 4
  5. 5. 4/26/2012Class E: • Ethylene production enhancement • Proxy® (ethephon) • Foliar • Use- poa seed head suppressionTurfgrass EstablishmentApplications Class A products are often useddue to: • Reduction in competitiveness of existing species when overseeding. • Seeding germination and development is normal because of: Late gibberellin synthesis inhibition of class A are foliar absorbedManagement of Poa annuaClass C products often used: •Direct suppression of seedhead formation 5
  6. 6. 4/26/2012 Chicago Golf Club (Kane 2001) Mixed Bentgrass & Poa- 0.5” H.O.C. 18th Fairway Proxy = Class E, Primo = Class A, Embark = Class C Foliar - Seed Head --- Foliar----- --- Foliar or Root --- Pebble Beach Golf Links, #14 Fairway Pebble Beach CA (Mahady, 2001 ) Seed Heads Seed Heads Color Quality % Cover % Control 5/15/2001 5/15/2001 5/15/2001 5/15/2001Treatments 42 DAT 42 DAT 42 DAT 42 DATUntreated Check 6.8 d 8.0 b 34.8 b 0%Proxy(5) 8.0 bc 9.6 a 1.4 c 96%Proxy(5)+Primo(O.25) 8.4 ab 9.8 a 0.6 c 98%Primo(O.25) 7.6 c 8.4 b 44.8 a 0% Typical green spray = 5oz / 1,000sq.’of Proxy plus .125 oz / 1000 square feet of PrimoWhat can affect PGR’s• Turfgrass species or cultivars• Weather conditions• Soil moisture• Root absorbed PGR’s may requireirrigation• Application timing• Plant health 6