Is annual bluegrass control practical?...Annual bluegrass biology •Adaptable: Equator‐Arctic Circle • Poaannua annua ‐winter annual •Lighter green, wider leaves, more seedheads

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Is annual bluegrass control practical?

Zac Reicher

http://turf.unl.edu/

[email protected]

http://turf.unl.edu

Does annual bluegrass control make sense?

Question

On a given area:

1. Do you try to control Poa?

2. Do you try to control sometimes and try to favor at other times?

3. Do you try to favor Poa?

Why desirable?

• Fine bladed

• Withstands low mowing

• Forgiving – recovers quickly from seed

• Too expensive to control

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Why a weed

• Apple‐green color

• Seedheads in late spring affect ball roll on greens, appearance

• Susceptible to snow molds, winterkill, ice cover, desiccation

• Often thins/dies in extended summer heat

• Limited water stress tolerance= increased labor and irrigation frequency

• Susceptible to many diseases like anthracnose and summer patch

• Susceptible to death by water immersion

• Susceptible to widespread death

Annual bluegrass biology

• Adaptable: Equator‐Arctic Circle

• Poa annua annua ‐ winter annual

• Lighter green, wider leaves, more seedheads

• Can flower within 45 days of germination

• More common in lawns, fairways, “rough type”

• Poa annua reptans– perennial

• Dark green, thin leaves, few seedheads

• Most do not flower until spring after overwintering

• More common in greens

• Continuum: true annual through long‐lived perennial

• Probably millions of biotypes in between

Annual bluegrass seed bank

• Can produce 360 seeds/plant/year

• Six years+ viability in seed bank

• Seed bank: • 110 viable seeds/in2 greens

• 70 viable seeds/in2 fairways

• Seeding rate = ~ 12‐15 seeds/in2

• Seeds viable within 24 hours of pollination

• 80% of seed in greens can germinate immediately

• Seed in fairways requires 4 months or chilling

• Can germinate in darkness

• Maryland golf course rough (Kaminski, et al):• 76% germinates from late‐Sep to mid‐Oct

• 24% germinates from Nov to May

Annual bluegrass ecology

• Each location exerts selection pressure determining the “current” populations of ABG biotypes

• Weather extremes are relative to the adapted biotype

• In Canada, snow mold was a major selection pressure determining the long‐term selection and eventual biotypes in the population (Bertrand et al, 2009)

• Heat, water, cold, environment, other management factors (including herbicides, TGR’s, etc?) can potentially control long‐term selection and eventual biotypes in the population

Theoretical change in Poa populations over time

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Annual bluegrass ecology

• Heat, water, cold, environment, other management factors (including herbicides, TGR’s, etc?) can potentially control long‐term selection and eventual biotypes in the population

• Limited stress leads to more genetic diversity (Poole et al, 2005)– Good for Poa encouragement/management and survival

– Bad for control

• May have to continually modify management if trying to control

Why doesn’t your whole family get the cold/flu?

• Overall health?

• Hygiene?

• Current exposure?

• Previous exposure?

• Genetics?

Why don’t Poa controls work 100%?

• Application accuracy?

• Tank pH?

• Spray volume?

• Timing/frequency of application?

• Weather?

• High enough rate?

• Susceptible Poa: too stressed, too healthy?

• Season?

• Crappy product?

• Genetics?– 45 plants sampled from 75 sq feet in three locations in MI, IN, NE = 5‐7

distinctly different populations/site

– Do genetics change over the season??

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Effect of repeated applications of Velocity on annual bluegrass populations. Structure plots of annual bluegrass samples collected in West Lafayette, IN. Thirty untreated control samples collected in West Lafayette (above) and 30 samples that were treated with 1 ozbispyribac to control annual bluegrass (below). Treatments were applied every two weeks from May through September, totalling 8 treatments per year from 2009‐2011. Seven distinct populations were found at this site. (University of Nebraska 2013)

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Can it be managed/kept alive?

• Depends on climate/geography

• Growth regulators: Proxy‐Primo (ethephon‐trinexapac) or Embark (melfuidide) for seedhead suppression and likely also improves summer survival (Poa can devote up to 50% of plant weight on seed heads)

• Growth regulator: Primo/T‐Nex – reduces vertical growth improves summer survival

• Control summer patch and anthracnose

• Water/rain frequently

• Aerify in fall with hollow tines to encourage germination

• High P and late fall‐applied N

Can it be domesticated?

• Commercial adaptability of greens‐type Poa?

• Unstable from generation to generation

• Limited mowing will push greens‐type Poa back to rough‐type (and vice versa) (typical of all turfgrassesthat form thinner leaves and denser canopies at lower relative mowing heights)

• Introducing minimal seed into a huge seedbank?

Mantia, J. M. and D. R. Huff. 2011. Instability of greens‐type phenotype of Poa annua L. Crop Science 51:1784‐1792.

Should control be attempted??

• Manage expectations

• Fortitude (season‐long)

• Control measures required forever (or at least 6 years because of seed bank)

• Support from decision makers

• Must manage above‐ground and below‐ground (seedbank)

• No silver bullets

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In search of the Silver Bullet for Poa

• What’s the best way to establish a resistant population of weeds, disease, insects, etc?

• With a genetically highly variable organism?

• Capable of surviving from the Arctic Circle to the Equator?

• With incredible reproductive capacity?

• With products that are only marginally effective?

Instances of herbicide‐resistant Poa annua (Heap, 2103)1 Belgium 1981 Simazine2 Belgium 1983 Amitrole3 Belgium 1993 Paraquat4 Czech Republic 1988 Atrazine5 France 1978 Atrazine6 Germany 1980 Atrazine7 Japan 1982 Simazine8 Norway 1996 Simazine9 The Netherlands 1981 Simazine10 United Kingdom 1981 Paraquat11 United Kingdom 1981 Simazine12 USA (Alabama) 1980 Simazine13 USA (Oregon) 1994 Ethofumesate14 USA (Oregon) 1994 Diuron15 USA (Oregon) 1994 Atrazine16 USA (North Carolina) 1995 Atrazine17 USA (Mississippi) 1996 Atrazine/Simazine18 USA (North Carolina) 1997 Pendimethalin/prodiamine19 USA (Virginia) 2001 Simazine22 USA (Tennessee) 2007 Dithiopyr/pendimathalin/prodiamine20 Australia (Victoria) 2009 Endothall21 USA (Missouri) 2010 Glyphosate23 USA (Tennessee) 2011 Glyphosate24 USA (Alabama) 2012 Bispyribac, etc25 USA (Alabama) 2012 Prodiamine

All control measures required

Non‐invasive

Invasive

Irrigation

Fertility

Disease management

No Primo (on CBG)

Aerification timing/tine selection

Mowing height/clipping collection

Growth regulators (Trimmit, Cutless)

Overseeding

Herbicides

Renovation/variety selection

Root mass/area (0‐1” depth) of 2 CBGs and 3 ABG’s maintained as greens over two years. (From Lyons et al, 2011)

Root mass/area at ~1.0 to 5.0” deep of 2 CBGs and 3 ABG’s maintained as greens over two years. (From Lyons et al, 2011)

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Irrigation

• Keep it dry

• Musser (1962): “Deep and infrequent irrigation reduces Poa annua”

• Slavens et al (2011)

• Keep it really dry!

• 12% = 8% >4% VWC

Lateral spread at harvest of the three Poa annua biotypes in response to the three irrigation treatments. Data points represent the mean of three repeated studies and bars indicate their standard errors. Slavens et al. 2011. Crop Science.

Fertility/disease/mowing

• Limit P

• Limit fall N

• Do not use ANY fungicides labeled for summer patch or anthracnose

• Catch clippings during seedhead formation ‐20% reduction over 3 years in seedbank(Gaussoin and Branham, 1989)

PrimoMaxx (T‐Nex)

• Excellent growth regulator for a wide variety of uses

• Does not favor desired species over ABG(other than KBG vs ABG)

• May increase Poa over time

% Poa change in PR/ABG Fairway over 3 years

Treatment 1997 1998 1999 3 yr

Control 5 4 ‐6 5

Prodiamine (PRE) ‐12 ‐14 ‐14 ‐40

Prograss (POST) ‐8 ‐10 ‐12 ‐30

Primo (PGR) 4 ‐3 ‐4 ‐6

PRE + POST ‐16 ‐13 ‐22 ‐53

PRE + PGR ‐6 2 ‐10 ‐10

POST + PGR 2 ‐4 ‐7 ‐10

PRE + POST + PGR ‐8 ‐8 ‐10 ‐15

LSD 4 7 9 10

Rossi, F.S. 2001. Annual bluegrass population dynamics in response to growth regulators and herbicides. International Turfgrass Society Research Journal. 9(Part 2): p. 906-909.

Percent bentgrass during season‐long applications of growth regulators in Hayden Lake ID (Baldwin and Brede, 2011)

RateMay 2009

Aug 2009

June 2010

Aug 2010

% change

Control - 47 52 48c 37b -10c

PrimoMaxx 1EC 11 oz/A 48 53 52b 35b -13c

Cutless 50WP 6 oz/A 45 69 60ab 63a 18a

Trimmit 2SC 10 oz/A 41 68 65a 73a 32a

Legacy 11 oz/A 48 53 50c 38b -10c

Legacy 22 oz/A 47 68 52b 45b -2b

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Percent bentgrass during season‐long applications of growth regulators in Spokane, WA (Baldwin and Brede, 2011)

RateMay 2009

Aug 2009

June 2010

Aug 2010

% change

Control - 49 53b 48c 43c -6d

PrimoMaxx 1EC 11 oz/A 49 69a 56b 50bc 1cd

Cutless 50WP 4 oz/A 46 59b 56b 55bc 9bc

Cutless 50WP 8 oz/A 53 71a 70a 75a 22ab

Trimmit 2SC 10 oz/A 45 70a 75a 84a 39a

Legacy 11 oz/A 49 59b 53bc 53bc 4c

Legacy 22 oz/A 43 70a 66ab 61b 18b

Primo on bluegrass?

• IL research suggests it will reduce ABG in KBG

• Improves density of KBG which may reduce ABG

• 26 oz/A applied every 400 GDD(Daily high/Daily low)/2

Poa control in KBG fairway after season‐long growth regulator applications (Branham Univ of Illinois 2013)

Treatment oz/A Interval % Poa Control

10/10/13Check ‐ ‐ 0 a

Primo 26 Monthly 4 a

Primo 26 400 GDD 32 b

Primo 17.5 400 GDD 8 a

Trimmit+Primo 8 + 26 800 GDD 31 b

Trimmit 8 800 6 a

Cutless 8 800 2 a

Cutless+Primo 8 + 26 800 GDD 36 b

Effect of Primo interval on clipping yield of CBG(Kreuser and Soldat, Univ of Wisc.)

0.125 oz/M (5.5 oz/Acre) 0.250 oz/M (11 oz/Acre)2008 predicted

Effect of Primo rate on CBG clipping yield (Kreuser and Soldat, Univ of Wisc.)

Loss of efficacy when below this line

Aerification

• Brings up seeds and creates a great seedbed

• Avoid creating the seedbed when Poa is germinating in fall

• Is aerification even needed?

• Yes on compacted/soil areas, areas with high OM/thatch buildup

• Maybe not on

– Sand greens or soil‐based with significant sand layer built up

– With no significant thatch or organic matter layers

• Aerify in summer when Poa is not germinating

• Solid tines where appropriate

• Aerify in spring if Poa is needed ASAP to recover from winter damage

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Overseeding/renovation

• Likely best option for heavy infestations and or heavily damaged areas

• Mid to late August for cool‐season grasses on most areas

• Golf courses:

– Poa germinates in the fall

– Seeding should be much earlier in summer

– Aggressive Poa controls require pre/post seeding

All control measures required

Non‐invasive

Invasive

Irrigation

Fertility

Disease management

No Primo (on CBG)

Aerification timing/tine selection

Mowing height/clipping collection

Growth regulators

Overseeding

Herbicides

Renovation/variety selection

New areas w/minimal Poa

• Annual type will be first invader

• Hand picking

• Herbicide dobbers

• PRE herbicides should work

– Tenacity on bare soils/new seedings

– Dimension/Barricade/Pendimethalin


Treatment 1997 1998 1999 3 yr

Control 5 4 ‐6 5



Primo (PGR) 4 ‐3 ‐4 ‐6

PRE + POST ‐16 ‐13 ‐22 ‐53

PRE + PGR ‐6 2 ‐10 ‐10

POST + PGR 2 ‐4 ‐7 ‐10

PRE + POST + PGR ‐8 ‐8 ‐10 ‐15

LSD 4 7 9 10


Annual bluegrass control on greens

• Growth regulators work great on fairways, but low mowing heights limit spread of CBG on greens

• Few labeled products

• Previous work early (90’s) on these growth regulators show little effect on northern greens– Weather doesn’t help tip the balance as much

– But studies were done with “old fashioned” application schedules

% Poa cover rated visually. Treatment means are averaged over 7 treatments.

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Growth regulators

• When most effective, cause the most disruption in play and discoloration

• Trimmit

• Cutless

• Legacy

Percent bentgrass during season‐long applications of growth regulators in Spokane, WA (Baldwin and Brede, 2011)

RateMay 2009

Aug 2009

June 2010

Aug 2010

% change

Control - 49 53b 48c 43c -6d

PrimoMaxx 1EC 11 oz/A 49 69a 56b 50bc 1cd

Cutless 50WP 4 oz/A 46 59b 56b 55bc 9bc

Cutless 50WP 8 oz/A 53 71a 70a 75a 22ab

Trimmit 2SC 10 oz/A 45 70a 75a 84a 39a

Legacy 11 oz/A 49 59b 53bc 53bc 4c

Legacy 22 oz/A 43 70a 66ab 61b 18b

Most effective treatments also most commonly reduced visual quality

Percent bentgrass during season‐long applications of growth regulators in Hayden Lake ID (Baldwin and Brede, 2011)

RateMay 2009

Aug 2009

June 2010

Aug 2010

% change

Control - 47 52 48c 37b -10c

PrimoMaxx 1EC 11 oz/A 48 53 52b 35b -13c

Cutless 50WP 6 oz/A 45 69 60ab 63a 18a

Trimmit 2SC 10 oz/A 41 68 65a 73a 32a

Legacy 11 oz/A 48 53 50c 38b -10c

Legacy 22 oz/A 47 68 52b 45b -2b

Most effective treatments also most commonly reduced visual quality

Poa annua control on greens in IN, MI, KY, NE

Product Rate Freq Dates Total apps

Velocity 17.6 SG 1 oz/A 2 wks May‐Sep 8

Velocity 17.6 SG 2 oz/A 2 wks Aug‐Sep 4

HM9930 130 oz/A 5 mo Apr, Aug 2

Trimmit 2SC 8 oz/A16 oz/A

2 wks2 wks

Apr‐May, Aug‐SepJune‐July

84

Cutless MEC 8 oz/A16 oz/A

2 wks2 wks

Apr‐MayMay‐Aug

57

Legacy 10 oz/A 2 wks Apr‐Sep 12

Primo Maxx 11 oz/A 2 wks Apr‐Sep 12

Applications made for 3 or 4 consecutive years, other than in KY

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Results to date…

• Poa populations in all treatments (including the untreated check) drop significantly and equivalently by late summer

% Poa cover rated visually. Treatment means are averaged over 7 treatments.

Results to date…

• No significant phyto/damage to CBG (EVER)

• Though data were recorded as often as every two weeks during the growing season at each location (91 observations over 4 years and 4 locations), the best treatment was different from the check 37% of the time

• Manage expectations!

• Highly variable control among locations

• Helps to explain highly variable anecdotal results from superintendents

Indiana Summary – ABG Cover

Initial

5/15/09 5/11/10 5/10/13 4/26/12 5/10/13

Final

5/10/13

Treatment % cover % change

Velocity 17.6 SG 43 49 ab 18 abc 10 26 a ‐37 a

Velocity 17.6 SG 45 40 bc 15 bc 7 19 ab ‐58 abc

HM9930 56 47 ab 11 cd 3 6 cd ‐89 d

Trimmit 2SC 39 15 d 2 d 5 2 d ‐95 d

Cutless MEC 41 26 cd 9 cd 2 11 c ‐75 cd

Legacy 34 37 bc 11 cd 6 13 bc ‐61 bc

Primo Maxx 43 56 a 25 ab 15 19 ab ‐56 abc

Untreated 49 54 a 28 a 15 22 a ‐50 ab

Michigan Summary – ABG Cover

Initial

5/18/09 5/27/10 5/19/13 4/18/12 5/10/13

Final

5/10/13


Velocity 17.6 SG 27¶ 39 bc 44 a 52 ab 50 a 93 a

Velocity 17.6 SG 25 33 c 38 ab 51 ab 46 a 88 ab

HM9930 29 43 ab 44 a 44 b 40 ab 45 bc

Trimmit 2SC 27 31 c 12 c 14 d 28 c 5 c

Cutless MEC 30 39 bc 26 bc 27 c 33 bc 19 c

Legacy 25 42 ab 44 a 51 ab 46 a 92 a

Primo Maxx 30 49 a 54 a 60 a 49 a 74 ab

Untreated 28 49 a 51 a 61 a 49 a 81 ab

Nebraska Summary – ABG Cover

Initial

5/7/10 5/10/11 5/7/12 5/7/13

Final

5/7/13


Velocity 17.6 SG 31 19 c 12 abc 23 ab ‐24 bc

Velocity 17.6 SG 32 8 d 3 cd 17 b ‐47 c

HM9930 30 4 d 1 d 1 c ‐95 d

Trimmit 2SC 32 29 bc 11 bcd 18 b ‐43 c

Cutless MEC 37 44 a 22 a 30 a ‐16 abc

Legacy 32 37 ab 19 ab 32 a 2 ab

Primo Maxx 23 31 b 15 ab 24 ab 1 ab

Untreated 29 30 b 18 ab 32 a 13 a

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Area under the Poa progress curve (AUPPC)

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Check

Area under the Poa progress curve (AUPPC)

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Treatment Check

Overall Summary – ABG AUPPC

Treatment

Purdue Michigan Nebraska

Velocity 17.6 SG 17502bc 35938b 11851c

Velocity 17.6 SG 15938c 32088b 6648d

HM9930 12935d 35220b 3215d

Trimmit 2SC 7896e 18497c 12911c

Cutless MEC 11304d 21313c 20704a

Legacy 12486d 31200b 18197ab

Primo Maxx 18134ab 46769a 15442bc

Untreated 20213a 43011a 17951ab

Poa control in greens

• Maximize cultural control

• Experiment with what works1. Trimmit

2. Cutless

3. Legacy

4. Velocity

• Must use multiple approaches over many years (forever)

• Practical question #1: Controlling ABG in circular green with a square sprayer?

• Practical question #2 (again): What’s the best way to develop a resistant population??

Effect of repeated applications over three years of Velocity on annual bluegrass populations. Structure plots of annual bluegrass samples collected in West Lafayette, IN. Thirty control samples collected in West Lafayette (above) and 30 samples that were treated with 1 oz/A Velocity to control annual bluegrass (below). Treatments were applied every two weeks from May through September, totaling 8 treatments per year from 2009‐2011 (University of Nebraska 2013)

Effect of repeated applications over two years of Legacy on annual bluegrass populations. Structure plots of annual bluegrass samples collected in Lincoln NE. Thirty control samples collected in Lincoln (above) and 30 samples that were treated with Legacy to control annual bluegrass (below). Treatments were applied every two weeks from May through September, totaling 8 treatments per year from 2009‐2011 (University of Nebraska 2013)

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Next edition of greens height Poa control

• USGA funded

• IL, IN, NE

• Summer hollow tine vs traditional fall hollow tine

• Applied treatments:

1. FeSO4 @ 44 lbs/A on 4 week intervals (6 apps)

2. Velocity @ 2 oz/A on 1 week intervals Aug‐Sep (4 apps)

3. #1 + #2

4. Trimmit @ 16 oz/A on 4 week intervals (6 apps)

5. PoaCure @ 25.6 oz/A on 2 week intervals Aug‐Sep (4 apps)

6. #2 + Bensumec 4 LF @ 15 pints/A Aug + April

7. #4 + Bensumec 4 LF @ 15 pints/A Aug + April

• Two years of applications and final data in April 2016

PoaCure (Methiozolin, MRC‐01)• Only experimental so far

• Label likely in 2016‐2017?

• Greens only

• Root absorbed

• SLOW acting

• Mode of action still somewhat undefined

• 0.6 oz/1000 applied 2‐ 4 times 2 weeks apart fall or fall + spring

• Damage not common but still often enough to be troublesome

• Avoid apps near temps <32F

• Has tremendous potential

• A ton of research/practical use is underway, stay tuned

KBG Fairways: Tenacity?• Tenacity is not labelled for Poa annua• Very safe on KBG including seedlings and also PRYE seedlings• Three applications at 5.3 oz/A 7‐10 days apart is typical• More frequent applications improve control• Include 0.25% v/v NIS + 2.5% v/v UAN (urea‐ammonium nitrate

28% N)• 20 GPA most effective• 1.0 lb N/1000 w/urea shortly after applications start• Fall applications effective, but inconsistent with only 3 fall +/‐ 1

spring applications• Control from fall apps are equal to or better than Prograss• Univ of Illinois:

• >70F or hotter• 5 apps @ 3.2 oz/A applied 1‐ 2X/week

Photo taken April 2005 after 3 apps of Tenacity 0.166 lbs ai/A at 2 week intervals starting Oct 28 2004.

Photo taken April 2006 on Purdue’s Ackerman Course after various applications of Tenacity in fall 2005.

% Poa cover in fairway height bluegrass after three years of late summer/fall herbicide treatments at Firethorn GC (UNL, 2010)

Herbicide App timing 10/7/10 5/10/11 10/4/11 4/9/12 10/17/12 5/7/13

Check ‐ 8 19 25 29 13 46Tenacity 8 oz/A (PRE) Aug 6 21 8 19 15 53

Barricade 0.65 lb ai/A (PRE) Aug 9 27 15 20 11 16

Tenacity 8 oz/A X 2 (PRE) Aug + Nov 6 14 11 11 13 36

Barricade 0.65 lb ai/A X 2 (PRE) Aug + Nov 7 21 13 26 14 25

Tenacity 5.3 oz/A X 3 (POST) Oct‐Nov 9 11 27 17 25 8

Tenacity 8 oz/A X 2 (POST) Oct + Nov 8 19 38 34 30 8

Prograss 2 qts/A X 3 (POST) Oct‐Nov 8 15 25 22 13 9

Barricade 0.65 lb ai/A (PRE)Tenacity 5.3 oz/A X 3 (POST)

AugOct‐Nov

7 9 7 9 10 7

Barricade 0.65 lb ai/A X 2 (PRE)Tenacity 5.3 oz/A X 3 (POST)

Aug + NovOct‐Nov

5 6 2 3 4 5

Barricade 0.65 lb ai/A (PRE)Prograss 2 qts/A X 3 (POST)

AugOct‐Nov

5 17 6 9 7 10

Barricade 0.65 lb ai/A X 2 (PRE)Prograss 2 qts/A X 3 (POST)

Aug + NovOct‐Nov

5 11 12 15 10 16

LSD NS NS 17 15 13 21

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% Poa cover in fairway height bluegrass after three years of late summer/fall herbicide treatments at Firethorn GC (UNL, 2010)

Herbicide App timing 10/7/10 5/10/11 10/4/11 4/9/12 10/17/12 5/7/13

Check ‐ 8 19 25 29 13 46

Tenacity 8 oz/A (PRE) Aug 6 21 8 19 15 53

Barricade 0.65 lb ai/A (PRE) Aug 9 27 15 20 11 16

Tenacity 8 oz/A X 2 (PRE) Aug + Nov 6 14 11 11 13 36

Barricade 0.65 lb ai/A X 2 (PRE) Aug + Nov 7 21 13 26 14 25

Tenacity 5.3 oz/A X 3 (POST) Oct‐Nov 9 11 27 17 25 8

Tenacity 8 oz/A X 2 (POST) Oct + Nov 8 19 38 34 30 8

Prograss 2 qts/A X 3 (POST) Oct‐Nov 8 15 25 22 13 9


AugOct‐Nov

7 9 7 9 10 7


Aug + NovOct‐Nov

5 6 2 3 4 5


AugOct‐Nov

5 11 12 15 10 16


Aug + NovOct‐Nov

5 17 6 9 7 10

LSD NS NS 17 15 13 21

AUPPC in fairway height bluegrass after three years of late summer/fall herbicide treatments at Firethorn GC (UNL, 2010)

Herbicide App timing AUPPC

Check ‐ 11186 a

Tenacity 8 oz/A (PRE) Aug 10542 a

Barricade 0.65 lb ai/A (PRE) Aug 10267 a

Tenacity 8 oz/A X 2 (PRE) Aug + Nov 7214 a

Barricade 0.65 lb ai/A X 2 (PRE) Aug + Nov 10263 a

Tenacity 5.3 oz/A X 3 (POST) Oct‐Nov 7406 a

Tenacity 8 oz/A X 2 (POST) Oct + Nov 10937 a

Prograss 2 qts/A X 3 (POST) Oct‐Nov 8449 a


AugOct‐Nov 4539 a


Aug + NovOct‐Nov 2687 a


AugOct‐Nov 6051 a


Aug + NovOct‐Nov 5920 aLSD NS

Tenacity Control of Poa 2009 Trials University of IllinoisTreatments (lbs ai/A) Formulation

oz/A/appInitiated 5/6/09

% Poa Ctrl 7/2/09

Initiated6/2/09

% Poa Ctrl8/4/09

Initiated 7/24/09% Poa Ctrl9/18/09

Control 2 c 7 c 0 d

0.05 ; 3x/wk, 10 apps 1.6 86 a 61 ab 93 a

0.1 ; 3x/wk, 5 apps 3.2 39 b 18 bc 95 a

0.166 ; 3x/wk, 3 apps 5.3 0 c 39 abc 51 bc

0.05 ; 2x/wk, 10 apps 1.6 85 a 65 a 78 ab

0.1 ; 2x/wk; 5 apps 3.2 80 a 46 abc 97 a

0.1 ; 1x/wk; 5 apps 3.2 57 b 28 abc 44 c

0.025 ; 3x/wk; 10 apps 0.8 ‐ ‐ 88 a

0.075 ; 2x/wk; 7 apps 2.4 ‐ ‐ 96 a

LSD (P=0.05) 25 45 27

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KBG Fairways: Xonerate

• Amicarbazone (Now FMC – future uncertain in north)

• Good activity on Poa

• Narrow margin for safety on bent, but better safety margin on KBG

• Apply in late spring/summer >80F, not in fall

• Partially root absorbed so water in

• Wait only 1 week to apply after seeding

• Wait 4 months to seed after application

• Maybe synergism on Poa annua as well as Poa trivcontrol when applied with Tenacity?

Tenacity + Xonerate?

• Preliminary Illinois data

• Start in mid‐to late summer

• Initial application

• 4 oz/A Tenacity

• 1.4 oz/A Xonerate 4S

• 1.0 lb N/M Urea in or close to application

• Repeat applications (every 3‐4 days)

• 3 oz/A Tenacity

• Safe on KBG, unknown on other species

Primo on bluegrass?

• IL research suggests it will reduce ABG in KBG

• Improves density of KBG which may reduce ABG

• 26 oz/ A applied every 400 GDD(Daily high/Daily low)/2

Poa control in KBG fairway after season‐long growth regulator applications (Branham Univ of Illinois 2013)

Treatment oz/A Interval % Poa Control

10/10/13Check ‐ ‐ 0 a

Primo 26 Monthly 4 a

Primo 26 400 GDD 32 b

Primo 17.5 400 GDD 8 a

Trimmit+Primo 8 + 26 800 GDD 31 b

Trimmit 8 800 6 a

Cutless 8 800 2 a

Cutless+Primo 8 + 26 800 GDD 36 b

PRYE Fairways: Prograss• Requires harsh winter

• Reduces cuticle

• Rates can be high enough on PRYE

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Treatment 1997 1998 1999 3 yr

Control 5 4 ‐6 5



Primo (PGR) 4 ‐3 ‐4 ‐6

PRE + POST ‐16 ‐13 ‐22 ‐53

PRE + PGR ‐6 2 ‐10 ‐10

POST + PGR 2 ‐4 ‐7 ‐10

PRE + POST + PGR ‐8 ‐8 ‐10 ‐15

LSD 4 7 9 10


CBG or PRYE Fairways: Velocity• “New” formulation 17.6 SG is easier to use

• Apply when temps >70F

• Summer plus early fall

• Check label for specifics

• Experiment yourself

ABG control in CBG fairways 2013 (Omaha CC)

AUPPC# Herbicide(s) Rate Timing 9/29/11 4/9/12 10/5/12 5/21/131 UTC 22 43 14 312 Velocity 4 oz/A Mid June + 3wk 7 22 3 93 Velocity 6 oz/A Mid June + 3wk 7 23 3 104 Velocity 4 oz/A Mid June + 3wk 4 17 1 6

Velocity 4 oz/A Early Sept +3wk 5 Velocity 6 oz/A Mid June + 3wk 4 14 1 1

Velocity 6 oz/A Early Sept +3wk6 Velocity 4 oz/A Mid June + 3wk 8 29 2 8

Dithiopyr 0.38 lb ai/A Early Sept7 Velocity 6 oz/A Mid June + 3wk 7 30 4 7

Dithiopyr 0.38 lb ai/A Early Sept8 Velocity 4 oz/A Mid June + 3wk 5 18 1 2

Velocity 4 oz/A Early Sept +3wkDithiopyr 0.38 lb ai/A Early Sept

9 Velocity 6 oz/A Mid June + 3wk 4 13 1 1Velocity 6 oz/A Early Sept +3wk Dithiopyr 0.38 lb ai/A Early Sept

10 Dithiopyr 0.38 lb ai/A Early Sept 22 44 17 39LSD (0.05) 5 12 5 3

ABG control in CBG fairways 2013 (Omaha CC)

# Herbicide(s) Rate Timing AUPPC1 UTC 26,166 a2 Velocity 4 oz/A Mid June + 3wk 11,025 b3 Velocity 6 oz/A Mid June + 3wk 10,309 b4 Velocity 4 oz/A Mid June + 3wk 6939 bc

Velocity 4 oz/A Early Sept +3wk 5 Velocity 6 oz/A Mid June + 3wk 5187 c

Velocity 6 oz/A Early Sept +3wk6 Velocity 4 oz/A Mid June + 3wk 10,386 b

Dithiopyr 0.38 lb ai/A Early Sept7 Velocity 6 oz/A Mid June + 3wk 10369 b

Dithiopyr 0.38 lb ai/A Early Sept8 Velocity 4 oz/A Mid June + 3wk 6778 bc

Velocity 4 oz/A Early Sept +3wkDithiopyr 0.38 lb ai/A Early Sept

9 Velocity 6 oz/A Mid June + 3wk 4794 cVelocity 6 oz/A Early Sept +3wk Dithiopyr 0.38 lb ai/A Early Sept

10 Dithiopyr 0.38 lb ai/A Early Sept 28352 aLSD (0.05) 4580

Summer Velocity

PRYEUntreated

PRYE

CBG Fairways: Growth regulators• Trimmit

• Cutless

• Applications every 2‐4 weeks (WI data indicates 300 GDD)

• Important in spring and fall when Poa is growing rapidly

• But be careful with frost!

16

Primary options for Poa control in fairways

KBG PRYE CBG

PRE’s X X X

Cutless X

Trimmit X

Primo X

Tenacity X (not labeled)

Velocity X X

Prograss x X x

Xonerate X(?)

Reseed with PRYE late in summer or

early fall

Poa germs and outcompetes PRYE in late fall

Poa outcompetes PRYE all winter

More Poa than previous year by

late spring

Poa PRYE thins in summer

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Breaking the cycle

• Control Poa?

• Choose different overseeding species for fairways?

• Seed prior to decline?

• Combine seeding and aggressive herbicides to limit Poa

Time to cover of KBG/PRYE mixes in lawn height turf in West Lafayette, IN. (Purdue/UNL 2013)

0

10

20

30

40

50

60

70

80

90

100

3 WAS 4 WAS 5 WAS 6 WAS

% turf cover

Weeks after seeding

100% KBG

90% KBG/10% PR

80% KBG/20% PR

70% KBG/30% PR

50% KBG/50% PR

100% PR

Seeded in 2008

LSD=10

NS

LSD=13

LSD=17

Long term amount of KBG in lawn height turf in West Lafayette, IN. (Purdue/UNL 2013).

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Year 1 Year 2 Year 3 Year 4

% Ken

tucky bluegrass

Years after seeding

100% KBG

90% KBG/10% PR

80% KBG/20% PR

70% KBG/30% PR

50% KBG/50% PR

100% PR

Seeded in 2007

LSD=27

LSD=23

LSD=4

Long term amount of KBG in lawn height turf in West Lafayette, IN. (Purdue/UNL 2013).

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Year 1 Year 2 Year 3

% Ken

tucky bluegrass

Years after seeding

100% KBG

90% KBG/10% PR

80% KBG/20% PR

70% KBG/30% PR

50% KBG/50% PR

100% PR

Seeded in 2008

LSD=11

LSD=12

Over‐ or reseeding fairways

• Perennial ryegrass or Kentucky bluegrass?

– What ratio?

• Aggressive post‐seeding herbicides

– Dramatically improves success of seeding

• Tenacity 5 oz/A 3 apps– 2,4,6 weeks after seeding

• Prograss 2 qts/A 3 apps– 2, 4, 6 weeks after seeding 0

10

20

30

40

50

60

70

80

90

100

% Cover 10/19/12 (d

esired/Poa)

100/0 90/10 80/20 70/30 50/50 0/100

Effect of seeding ratio (KBG/PRYE) and post‐seeding herbicides applied starting 2WAE on cover of desired turf vs Poa rated 6 weeks after early Sept seeding in Mead, NE, research farm (no Poa on site) (UNL 2012).

LSD=7

18

Effect of seeding ratio (KBG/PRYE) and post‐seeding herbicides applied starting 2WAE on cover of desired turf vs Poa rated in May after early Sept seeding in Mead, NE, research farm (no Poa on site) (UNL 2012).

0

10

20

30

40

50

60

70

80

90

100

% Cover 5/15/13 (desired/Poa)

% Poa

%Turf

100/0 90/10 80/20 70/30 50/50 0/100

LSD=NS

What Ratio of PRG:KBG?

Effect of seeding ratio (KBG/PRYE) and post‐seeding herbicides applied starting 2WAE on cover of KBG vs Poa rated in August following early Sept seeding in Mead, NE, research farm (no Poa on site) (UNL 2012).

LSD=21

0

10

20

30

40

50

60

70

80

90

100

% Cover 8/1/13 (K

BG/Poa)

Poa

KBG

100/0 90/10 80/20 70/30 50/50 0/100

Effect of seeding ratio (KBG/PRYE) and post seeding herbicides on cover of desired turf vs Poa rated 6 weeks after early Sept seeding at Lochland CC (Poa present) (UNL 2012).

LSD=22 for desired turf and Poa

0

10

20

30

40

50

60

70

80

90

100

% Cover 10/16/12 (d

esired/Poa)

100/0 90/10 80/20 70/30 50/50 0/100

0

10

20

30

40

50

60

70

80

90

100

% Cover 5/15/13 (desired/Poa)

% Poa

%Turf

100/0 90/10 80/20 70/30 50/50 0/100

Effect of seeding ratio (KBG/PRYE) and post seeding herbicides on cover of desired turf vs Poa rated in May after early Sept seeding at Lochland CC (Poa present) (UNL 2013).

LSD=18 for desired turf and Poa

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Effect of seeding ratio (KBG/PRYE) and post seeding herbicides on cover of KBG vs Poa rated in August after early Sept seeding at Lochland CC (Poa present) (UNL 2013).

LSD=25 for KBG, 19 for Poa

0

10

20

30

40

50

60

70

80

90

100

% Cover 8/13 (KBG/Poa)

% Poa

%KBG

100/0 90/10 80/20 70/30 50/50 0/100

Take home message so far

• Tenacity or Prograss immediately after seeding to minimize Poa

• 90% KBG/10% PRYE to maximize KBG after one year

• Study will continue for three more years

Post‐seeding Poa control options

• Tenacity on KBG or PRYE– PRE on bare soil– POST over turfed areas, 28 days after emergence

• Velocity on CBG, PRYE– POST two weeks after emergence

• Prograss– POST 1‐2 weeks after emergence of PRYE– POST 3‐4 weeks after emergence of CBG– POST 8 weeks after emergence of KBG

• Dithiopyr– Early POST with PRE residual– “Developed a good root system and uniform stand, and have received at least two mowings””

Safety of Velocity 17.6SG when applied over newly‐seeded L93 creeping bentgrass. Regardless of rate or timing, Velocity had no effect on cover by 8 weeks after emergence (WAE) (Purdue 2007).

April picture of late fall seeding of PRYE, no Poa control

20

April picture of late fall seeding of PRYE, Tenacity at emergence April picture of late fall seeding of PRYE, Tenacity at emergence

Zac Reicher

http://turf.unl.edu/

[email protected]

Documents

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