Download - Plant growth
![Page 1: Plant growth](https://reader037.vdocuments.us/reader037/viewer/2022100518/559cfc341a28abe4298b4871/html5/thumbnails/1.jpg)
4/26/2012
1
Plant 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
![Page 2: Plant growth](https://reader037.vdocuments.us/reader037/viewer/2022100518/559cfc341a28abe4298b4871/html5/thumbnails/2.jpg)
4/26/2012
2
• 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
Why PGR’s Continued:
Original classification
Type I and Type II growth regulators:
Type I
• Compounds foliar absorbed and inhibit cell division at the meristem
• Excellent seedhead control
What are PGR’s?
![Page 3: Plant growth](https://reader037.vdocuments.us/reader037/viewer/2022100518/559cfc341a28abe4298b4871/html5/thumbnails/3.jpg)
4/26/2012
3
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 stalk
What are PGR’s continued?
New Classification PGR’s- All reduce growth -
Class A:• Late gibberellic acid (GA) synthesis blockers (giberellic acids hormones responsible for cell elongation)
• Example Primo Max® (trinexapec-ethyl)
• Foliar absorbed
• Last 3-6 weeks depending on rate and use
Class A continued:
- 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
USE
![Page 4: Plant growth](https://reader037.vdocuments.us/reader037/viewer/2022100518/559cfc341a28abe4298b4871/html5/thumbnails/4.jpg)
4/26/2012
4
Class B:• Early GA synthesis blocker
• Trimmit® (paclobutrazol), Cutless®(flurprimidol)
• Root absorbed
• Use- poa reduction
Class 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 iron
Class 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
![Page 5: Plant growth](https://reader037.vdocuments.us/reader037/viewer/2022100518/559cfc341a28abe4298b4871/html5/thumbnails/5.jpg)
4/26/2012
5
Class E:• Ethylene production enhancement
• Proxy® (ethephon)
• Foliar
• Use- poa seed head suppression
Turfgrass Establishment
Applications Class A products are often used due 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 absorbed
Management of Poa annua
Class C products often used:•Direct suppression of seedhead formation
![Page 6: Plant growth](https://reader037.vdocuments.us/reader037/viewer/2022100518/559cfc341a28abe4298b4871/html5/thumbnails/6.jpg)
4/26/2012
6
Chicago Golf Club (Kane 2001) Mixed Bentgrass & Poa- 0.5” H.O.C. 18th Fairway
Proxy = Class E, Primo = Class A, Embark = Class CFoliar - 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 Primo
• Turfgrass species or cultivars• Weather conditions• Soil moisture• Root absorbed PGR’s may require irrigation• Application timing• Plant health
What can affect PGR’s