1

Herbaceous Perennial Weed Control in Landscapes

Dr. Hannah MathersMathers Environmental Science Services

Consultant

Efficacy – ↑ weed controlPhytotoxicty - ↓ injury

Beauty without the risk

HAND WEEDING• Before each “scheduled” herbicide application

- hand weeding is done.• Hand weeding, not more than 1-2 days prior to

scheduled applications.• If for any reason weeds are ready to seed

before scheduled application, weeds are pulled and half rate of preemergence herbicide applied.

0

20

40

60

80

100

120

140

160

180

Mar April May June July August Sept Oct Nov

Weed Counts

Month of Emergence

Weed Emergence Continuum

Shepherd's Purse Groundsel Barnyard Grass Spurry Violet

Preemergence:

Before emergence

Soil-active

Activity affected by soil

conditions and envir.

Do not kill dormant or germinated

Incorporate = barrier

Postemergence:

Plant- active

Activity affected by plant conditions

and envir.

Contact and systemic

1” germ

1/21/2015

Classification of Herbicides

SelectiveControls weeds without

injury to certain plants

Tolerant plants on label

NonselectiveWill kill any plant or plant part applied to

For non-crop areas or directed sprays

Nonselective

1/21/2015

Selective Grass Postemergence:

• Acclaim- fenoxaprop-p• Envoy- clethodim(most effective on Bermudagrassand tall fescue) (0nly one for bluegrass)• Fusilade TO- fluazifop-p-butyl(60% burn on river birch and burning bush)• Vantage (13%) - sethoxydim• Sedgehammer- halosulfuron-methyl (control of

nutsedge as a early post application)• Asulam – conifers, leafless decid. = horseweed

and horsetail

(young grasses only – no effect on sedges – except sedgeH)

Selective Broadleaf Postemergence:

• Basagran TO- bentazon(also nutsedge control) • Garlon- triclopyr• Lontrel or stinger - clorpyralid (most

effective on Asteraceae and leguminaceae– (thistles, groundsel, horseweed, clovers, dock) (over the top of Pw, Ps, Sn, Sw, Cw, Taxus) can be root absorbed – so no drench plant

No docks, lambsquarters, smartweed• Trimec- 2,4-D plus MCPP plus dicamba

2

Maintain the chemical barrier• Disturbing the barrier = Failure

i. Wind tip

ii. Hand weeding

iii. Excessive irrigation

iv. Heat*

Top ½” –barrier zone

1/21/2015

Preemergence herbicides• Most will not kill weeds present at time of application

– Exceptions ( must be “small” weeds)

Goal – oxyfluorfen –PPO inh.

SureGuard – flumioxazin – PPO inh.

Ronstar- oxadiazon – PPO inh.

Gallery – isoxaben – cellulose inh.

Indaziflam – Marengo G or CS or

Specticle G (landscape)

1/21/2015

•Granular combo preemergence

Snapshot, Preen Plus (Isoxaben + Trifluralin)

Rout - Oxyflourfen (Goal) + Oryzalin (Surflan) – esp. Fall

OH2 – Oxyflourfen (Goal) + Pendimethalin (Pendulum)

RegalStar (Oxadiazon + Prodiamine)

Jewel (Oxadiazon + Pendimethalin) – Everris

Harrell’s 75 (oxyfluorfen + trifluralin) –HGH75, HGH63

Biatholon• Biathlon- oxyfluorfen and prodiamine

• New - Verge granule technology

• The rate is 100 lbs. per acre with a maximum of two applications per acre per year.

• Re-applications may be made at three-month intervals.

• Controls grass and broadleaf weeds in field and container ornamentals, ground maintenance and other non-crop areas.

• Biathlon may also be used on evergreens and conifer trees including Christmas tree and conifer farms.

Biathlon Rosa ‘Knockout’ (North Branch and Studebaker)

Hydrangea macrophylla ‘Endless Summer’

1 application onlyWash off immediately

Hydrangea arborescens ‘Invincibelle spirit’Azalea viscosum

Hemerocallis ‘Stella d oro’

Not OK

0

2

4

6

8

10

12

14

Oxalis 90 DAT Bittercress 90 DAT Spurge 60 DAT

Weed

s

Weed counts days after treatment (DAT) C. Gilliam 2011, Auburn Univ.

Biathlon 100 lb

Biathlon 200 lb

Product R

Check

•Non-combo Granulars

Pendulum 2G - pendimethalin

Corral 2.68G - pendimethalin

Barricade 65WG - prodiamine

Treflan 5G (TR10) - trifluralin

Ronstar G - oxadiazon

Devrinol 2G - napropamide

XL 2G – oryzalin

Single Active: Broad Spectrum

• Casoron 4G – Dichlobenil – Annual and perennial weeds in woody ornamentals

• Sureguard 51 DG and BroadStar 0.25 G –Flumioxazin – Annual Grasses and Broadleaf weeds, nursery, christmas tree plantation

• Marengo G and SC

1/21/2015

OHP, Inc., Mainland, PA launchedgranular 9/2013 – Nursery containers EcoGranule™ formulation Long-lasting - Soil degradation 150 days Less applications Low a.i./ac – 0.0224% Indaziflam 0.25” to activate within 21 days Non-volatile, does not move in soil once watered

in

Marengo G®

3

lb a.i. / A

• Snapshot TG 150 lb/A Isox + Trifl 3.75

• OH-2 100 lb/A Oxyfl + Pend 3.0

• Rout 100 lb/A Oxyfl + Oryz 3.0

• Regal O-O 100 lb/A Oxyfl + Oxad 3.0

• Ronstar 2G 200 lb/A Oxadiazon 4.0

• BroadStar 0.25G ® 150 lb/A Flumioxazin 0.375

Marengo G ® 200 lb/A Indaziflam 0.0448

Standard Use Rates Cellulose Inhibitors (Group 20 & 21)

BenzamideGallery 75 DF IsoxabenSnapshot 2.5 TG Isoxaben + trifluralin

Nitrile Casoron 4G Dichlobenil

Group 20

Group 21

AlkylazineAlion -Orchard Indaziflam Specticle -LandscapeMarengo G -Nursery cont.

Group 29

VergeGranule™ Marengo® - 2014

• ‘Verge’ technology refers to granule -same as Oil-Dri Corp. of America

• Verge already implemented on the Biathlon (oxyfluorfen + prodiamine) herbicide

• Verge also used with Talstar® XTRA granular insecticide (FMC)

Verge technology

Eco

“Verge” vs “Eco” technology

• Eco

– Very small

– Easily blown by wind

– Hangs up in the foliage

• Verge

– Low dust

– Uniform distribution of granule

– Less phytotoxicity (less hang up in foliage*)

4.2

4.8

2.4

1.2

0.4

0.0

5.6

0.0

1.0

2.0

3.0

4.0

5.0

6.0

100 lbs 100 lbs 200 lbs 200 lbs 400 lbs 400 lbs --

Verge Eco Verge Eco Verge Eco Untreated

Wee

d c

ou

nts

bc c

abc

ab

ab

a

c

c

c

abc

ab

ab

a

Weed Counts - 12 WAT Oxalis stricta

Herbicide Rate/ac 12WAT fresh wt. (g)

Verge 100 lbs 0.0 a

Eco 100 lbs 0.0 a

Verge 200 lbs 0.0 a

Eco 200 lbs 0.0 a

Verge 400 lbs 0.0 a

Eco 400 lbs 0.0 a

Untreated -- 60.3 b

lsmeans (α = 0.05) Conclusions

• Marengo is an excellent herbicide - 200 and 400 #/ac through 12 WAT with all species investigated

• Loss of control with esp. broadleaf sp. at 8 WAT with 100 #/ac

• No significant differences in efficacy or duration of efficacy between the Eco or Verge formulations

• However, phytotoxicity is expected to be greatly reduced with improved VergeGranule in future studies

Verge technology

Marengo G and Biathlon G

Biathlon OHP – Oxyfluorfen + prodiamine

Eco

Featherlite side boom

Carbon fiberFeatherlite T-boom

4

KLC-5 nozzle - for backpack spray

FIELDJET NOZ, BRASS

Product Description:

Item number: S1/4KLC-5

$25.34 Chemical Containers, Inc. 413 ABC RoadLake Wales, FL 33859-6849Phone - 863-638-1407

Spray swath14-ft.

Pressure regulator Liquid Preemergence Ornamental Herbicides

SurflanPendulumSureGuardGalleryGoalTowerPennant MagnumDimension

Dimension

2EW at 0.5 lb

ai/A +

Gallery SC at

1.0 lb ai/A

Dithiopyr +

Isoxaben

IndaziflamF6875 -Sulfentrazone + prodiamineV-10233 -

TREATMENT PROTOCOL FOR GRANULAR APPLICATIONS

• Dry foliage• Irrigate 20 – 25 minutes, to

wash off the granules.• Wind not more than 5 - 10 mph.• Bad for whorled leaves and

Hydrangea

TREATMENT PROTOCOL FOR SPRAYING

• Wet foliage – dew or 5 to 10 minutes irrigation.

• Spray.• Irrigate ASAP 20 - 25 minutes to wash

off herbicides.• Wind not more than 5-10 mph.

Physical Control - mowing

- cultivation

- hand weeding

- Mulching- burning

- mowingMulch kept 4 - 6 “ away from trunk

HYG-1083-96Drs. Rose & Smith

From: Pests of Landscape Trees and Shrubs,

University of CaliforniaBeds – 2-2.5” deep = heavy soils

Beds – 3-4” deep = well drained, dry clim. Physical alone

Unt.

Unt.P

ine N

ug.

Unt.D

oug.f

ir

Unt.C

ypres

s

Unt.H

ardwo

od

Unt.P

ennM

ulch

Unt.R

icehu

lls

Unt.C

ocoa

shells

c c

d

a a

e

b

a

0

1

2

3

4

5

6

7

8

9

10

Ratin

gs

Mulch Types

Efficacy Ratings of Untreated Mulches at 45 DAT

Scale 0 to 107= Acceptable

(inhibition of germination)

Efficacy of Untreated Mulches at 130 DAT

2.625abc

2.75abc

0.125bc

3.5a3.25

ab2.25

a

2.75a

1.125c

0

1

2

3

4

5

6

7

8

9

10

Unt.

Unt.P

ine N

ug.

Unt.D

oug.

fir

Unt.C

ypre

ss

Unt.H

ardw

ood

Unt.P

ennM

ulch

Unt.R

icehu

lls

Unt.C

ocoa

shell

s

Mulch Types

Ratin

g

Physical alone

(growth suppression)

1/21/2015

9.2

4.5

7.8

1.8 2. 2

10

3.7

1.31.9

1.5 1.22.1

0

1

2

3

4

5

6

7

8

9

10

P.N. +1xSur P.N. +1xFlum P.N. + .5xSur P.N. + .5xFlum Untreated P.N H.B. + Flum.

TreatmentFig.3. Comparison of efficacy and phytotoxicity for the Pine Nuggets and one Hardwood Bark treatment evaluated by rated scores at 45 DAT.

Physical + Chemical alone Pine Nuggets + Surflan Control

115 DAT

5

Ronstar on top of mulch - no damage to plants

Ronstar no mulch -severe damage to plants

Rout moved into alleys with washing soil - no weeds between plots

With mulch, Rout stayed where it was applied. Weeds grew between the plots

Larry Kuhns, 2006

Herbicide 2 applications

Herbicide plus mulch = 1 ?

Herbicide PlacementPreemergence Herbicide Over Under

Pennant

Snapshot

FreeHand

Snapshot

Treflan

Surflan

Pendulum

Factor

Ronstar

OH II

Rout

Specticle

Weed Pharm (Vinegar) (20% acetic acid)

Diuron (Karmex)

SureGuard or BroadStar

Over or Under?

Control

Casoron U Pine 8.2

By weight and pooled over dates 11 tmt. gave < 3 g of weed growth, control= 21g

120 DAT New Beds Vs. Old

• Products that go under = new

• Products that go over = existing, no new mulch

• Products that go under = existing with new mulch on top

1/21/2015

FreeHand Vs. Snapshot

Treatment Rate 2 wat 4 wat 8 wat 12 wat

FreeHand 200 #/ac

9.3 8.7 8.7a 7.0b

Snapshot 200#/ac

9.0 8.0 6.8b 6.0c

Phytotoxicity

Salvia Geranium Snapdragon Impatiens Ageratum

FreeHand FreeHand 1.9 2.1 2.9 5.8* 0.8

Snapshot Snapshot 1.3 3.6* 2.0 3.7* 0.81/21/2015

Untreated Snapshot 200#

1/21/2015

FreeHand 200 # FreeHand 400 #

6

FreeHand

• Dimethenamid- p + pendimethalin (Freehand G) – BASF

• Freehand 1.75G, 150 lb/A= 1X, 450 lb/A = 3X

• Excellent, broad-spectrum weed control

• One of the longest-lasting preemergence herbicides in container nurseries – Joe Neal

• Landscape and nursery control weeds other products not controlling

FreehandFreeHand 1.75G Landscape

Uses

Application Rate

(lbs product /Acre)

Amount (lbs product /1,000 sq. ft.)

Amount (lbs

product/100 sq. ft.)

100 2.30 0.23

150 3.45 0.34

200 4.60 0.46

Snapshot @ 200 lb/A

OH2 @ 100 lb/A BroadStar @ 150 lb/ A

FreeHand 150 lb/A

FreeHand 1.75G Control Dr. Joe Neal, North Carolina State Univ.

spurge crabgrass bittercressdoveweed eclipta

2007 Trial, Wilmington, NC

10 WAT

EFFICACY OF PENDIMETHALIN FORMULATIONS AS AFFECTED BY MULCH TYPE

HARDWOOD MULCH (shredded)

21 DAT

2.0 lb ai/A

UNTREATED PENDULUM EC AQUA CAP

EFFICACY OF PENDIMETHALIN FORMULATIONS

AS AFFECTED BY MULCH TYPE

PINE BARK MULCH (shredded)

21 DAT

2.0 lb ai/A

UNTREATED PENDULUM EC AQUA CAP

Indaziflam – Marengo (G)Alion – Fruit trees

Specticle G – Turf, Landscape

OHP - Marengo - NurseryBayer – Specticle - LandscapeCell wall inhibitor – new MoALong-lasting – 150 days Low application rate – 0.11 lb ai/acLess applications

Cellulose Inhibitors

Cell Wall Inhibitor

20, 21, 29

Casoron, GalleryIndaziflam

Bayer landscape trial 2013 - Waterman Farm, Columbus, OH.A. Specticle 100 lb./ac with mulch, B. Specticle 100 lb./ac un-mulchedC. Control at 3 MAT.

A

B C

A. FreeHand with mulch, B. Snapshot and mulchC. Weedy Check with no mulch at 3MAT.

7

Treatment Rate/ac

Eff no

mulch Eff w/mulch

Specticle 100 0.6 e 5.8 cd

Specticle 150 6.3 bcd 5.9 bcd

Specticle 200 5.8 cd 7.8 ab

Snapshot 150 6.8 abc 8.3 a

FreeHand 150 5.3 cd 8.7 a

3 MAT

Untreated mulch

Gr under

Indaziflam at 11 WAT

Bio-Herbicide Treated Mulch

Dr. H. Mathers

Mr. Luke Case

Sheridan Nurseries, Georgetown, ON

Introduction

• 2005 Connecticut - first state to ban the applications of synthetic herbicides around K-8 schools and daycares.

• 2006 Quebec - ban all cosmetic pesticide applications

• 2008 Ontario - ban all cosmetic pesticides

• 2012 French Court - Monsanto guilty of chemical poisoning: Grain farmer, France - memory loss, headaches and stammering after inhaling Lasso in 2004.

• 2013 Holland - Glyphosate ban: France and Brazil to follow - Cancer

• 2014 Sri Lanka - Glyphosate ban - Kidney disease1/21/2015

Past five years: Significant rise in public concern regarding theuse of herbicides

Industry interest regarding alternative weed control methods ↑

Reduction of herbicides via bio-rationale and organic approaches required

An effective bio-herbicide is the “Holy Grail” of bio-pesticides

Introduction

1/21/2015

← Control

Vinegar – Pellets 5c →

Mathers and Case 2012 Trials – OSU

LEED Certified Bldg.

1/21/2015

10

8

10 9.6 9.69.2

9

8.4

7.67.4

6.6

4.6 4.6

1

0

1

2

3

4

5

6

7

8

9

10

90 DAT

1/21/2015

Conventional

Bio-herbicides

90 DAT

1/21/2015ControlVinegar <1”

8

1/21/2015

From studies conducted 2009-2013:

Developed four alleopathic plant extracts that have provisional patents (2013) via The Ohio State University, Technology and Commercialization Office (TCO)

2014 – Material transfer agreement signed – In effect

Introduction Objectives

1/21/2015

1. Determine the efficacy and duration of efficacy of four alleopathic plant extracts compared to other organic herbicides applied on two types of mulch

2. Assess the phytotoxicity of these different controls in field.

Only efficacy data will be presented as phytotoxicity was minimal.

Materials and Methods

1/21/2015

Creation of extracts:a. Branches were cut from

4 species, on or near OSU, Columbus, OH

b. Branches measured –Fresh weights collected

c. Samples placed 32°C drying oven for 1 week

d. Dry weights collected: calculate mg of dry weight /ml of solvent

Ailanthus altissima Picea pungens Pinus nigra Eleagnus angustiflolia

Materials and Methods

1/21/2015

Creation of extracts (con’t):

e. Grind all dried plant parts with laboratory Wiley mill.

f. 20% w/v stock solution prepared

g. Water added for various % solutions from stock

h. 50 ml water and 50 ml of the stock solution = 10% [ ].

Results

1/21/2015

Wood Pellets: ½ cup per 9 ft2

Ineffective in controlling weeds Even at 37 DAT, only commercially acceptable

weed control was with FreeHand 49 DAT, even FreeHand with wood pellets no longer

commercially acceptable. We had used ½ cup of pellets in 2012 trials in

gravel with success; however, in the field with no protection from wind and water by the irregular surfaces of a gravel site the pellets did not persist.

Data not shown

Results

1/21/2015

37 and 49 DAT > 7: All treatments 65 DAT > 7: 5 tmts: Eleagnus angustifolia

(Autumn olive) 3%, Ailanthus altissima (Tree of Heaven) 3%, Pinus nigra (Austrian Pine) 3%, Fiesta 10%, and 3% Austrian Pine + 3% Juglansnigra (Black Walnut)

105 DAT > 7: 3 tmts: Eleagnus angustifolia 6%, Pinus nigra 6% and 5% Pinus nigra + 5% Juglans nigra .

105 DAT - 2” pine nuggets + no herbicide = 2.8 rating

2” Pine Nuggets:

37 DATz 49 DAT 65 DAT 105 DAT

Treatment PNy PN PN PN

Blue Spruce 6% 8.4xw abc 8.4 ab 5.4 bcd 5.4 ab

Eleagnus 3% 9.2 a 8.6 ab 7.8 a 7.0 a

Ailanthus 3% 8.4 abc 8.2 ab 7.0 abc 5.4 ab

Austrian pine 3% 8.8 abc 8.2 ab 7.8 abc 7.0 aWeedPharm 10% +

Fiesta 10% 8.8 abc 8.2 ab 6.0 abc 3.8 bcd

WeedPharm 10% +

RO 6%8.2 bc 8.2 ab 4.8 cd 4.8 abc

10% Fiesta 9.0 ab 9.2 a 7.2 ab 5.4 ab5% Austrian Pine +

5% Juglans8.4 abc 8.8 ab 7.2 abc 7.0 a

FreeHand 8.6 abc 7.6 b 5.8 abc 5.6 ab

Control (no mulch) 6.0 c 5.6 b 1.6 e 2.0 d

lsmeans (α = 0.05)*> 7 = commercially acceptable, 0 no control

Results

1/21/2015

Pinus nigra (Austrian Pine) 3% + 3% Juglans nigra (Black walnut) = rating of 7.0 - picture taken, September 23, 2013 (3 MAT) at Waterman Farms, Columbus, OH, bio-herbicide trial

Results

1/21/2015

Control: pine nuggets only at 3MAT (rating 2.8).

9

Results

1/21/2015

Austrian pine + pine nuggets at 2MAT

Conclusions

1/21/2015

Horticultural vinegar performed well as in past trials to 50 DAT

Alleopathic extracts in 2013 trial = lower than in previous studies.

Even at these low rates three treatments were providing commercially acceptable control at 105 DAT, Eleagnus angustifolia 3%, Pinus nigra 3% and 3% Pinus nigra + 3% Juglans nigra.

1st yr with Juglans nigra - should be evaluated further in combination or alone

Acknowledgements

• Sheridan Nursery, Ontario

• Vineland Research and Innovation Center

• OSU – TCO and FOD (Grounds Department)

• USDA/ MI Department of Agriculture - Specialty Crop Block Grant

• MNLA

Hannah Mathers

614-371-0886

mathers326@gmail.comWeed Control

- Application technologies

- Application timing

- Trials for difficult weeds or sites