INVASIVE WEED MANAGEMENT - BugwoodCloud · Some Principles and Guidelines •We are surrounded by...

INVASIVE WEED MANAGEMENT

Dr. Steven G. Richardson

Reclamation Research Director

Some Principles and Guidelines

•Know your plants - weeds vs. natives

•Early detection of invasives - scouting

•Spot spraying early

•When you kill weeds you leave an ecological

“hole” (restoration or reinvasion)

•Sites left fallow invite invasion

•Eradication nearly impossible (follow-up)

•Competitive vegetation can slow invasion

•Good management

•Competitive cover crops

Florida Industrial and Phosphate Research Institute

Some Principles and Guidelines

•We are surrounded by weeds

•The soil is likely full of weed seeds

•Don’t aid weed spread

•Clean equipment

•Don’t let weeds go to seed (timely control)

•Rhizomes likely extend beyond foliage

•Thorough site preparation

Florida Industrial and Phosphate Research Institute

Control and Management

•Awareness

•Knowledge

•Motivation

•Resources

•Cooperation

Florida Industrial and Phosphate Research Institute

May require:

COGONGRASS MANAGEMENT

Dr. Steven G. Richardson

Reclamation Research Director

References

Control and Management of Cogongrass and Other

Exotic Grasses on Disturbed Lands in Florida.

2013. FIPR Institute Publ. 03-157-249http://www.fipr.state.fl.us/

Library & Publications. Our Publications. Reclamation. Control and

Management of Cogongrass… 03-154-249final

Management of Nuisance and Exotic Vegetation

on Phosphate Mined Lands in Florida. 2012. FIPR

Inst. Publ. 03-160-248http://www.fipr.state.fl.us/ .Library & Publications. Our

Publications. Reclamation. Management of Nuisance… 03-160-

248final

Florida Industrial and Phosphate Research Institute

Cogongrass Control

•Kill Rhizomes

•Stop Seed Production

Weed Management Techniques

• Tillage

• Mowing and/or grazing

• Biocontrol (insects or disease)

• Fire

• Soil fertility management

• Plant competition (shade, etc.)

• Herbicides – selective and nonselective

Florida Industrial and Phosphate Research Institute

Tilling

•Chisel plow

•Rototiller

•Disk

•Moldboard (turning) plow

Separate rhizomes from soil and

bring to surface to dessicate

Rhizome sprouting

Top kill (starve it)

Florida Industrial and Phosphate Research Institute

Mowing and Grazing

•Mowing favors bahiagrass over

cogongrass (may favor other short grasses)

•Reduces seed production

•Intense rotational grazing

•Young, new growth of cogongrass (after a

burn or mowing) can be grazed

•Burning is a better pretreatment (mowing

leaves “trash” on surface)

Florida Industrial and Phosphate Research Institute

Burning

•By itself – removes woody

competition and favors cogongrass

•Better pretreatment than mowing

for subsequent herbicide treatment

Florida Industrial and Phosphate Research Institute

Site Renovation

•Solid infestation

“Nuke” it

Repeat

Thorough site preparation

•Spreading into desirable vegetation

Selective herbicides

Repeat

Florida Industrial and Phosphate Research Institute

Herbicides for Cogongrass

• Imazapyr (Arsenal or Habitat)

Soil activity & residual, selective at lower rates

• Glyphosate (Round-up or Rodeo)

No residual, non-selective

• Fluazifop-butyl (Fusilade)

Selective grass killer (broadleaf competition)

• Sulfometuron-methyl (Oust) tank mix

• Aminocyclopyrachlor (Method) new

Kills broadleaves, too

Cogongrass Before Treatment Standing dead

matter

Fire to remove

standing dead matter

Cogongrass After Burning Flush of new

green growth

Treat When Leaf Area Is Sufficient

Maximize Uptake

Herbicidal Control of

Cogongrass

•Burn late summer (vs. mowing)

•Spray regrowth in fall

•Imazapyr 0.75 to 1.0 lb a.i./acre

•Glyphosate 4 to 5 lb a.i./acre

•Follow-up

Percent Cover at Tenoroc Sand Tailings Pile

Burned Sept. 2003, Sprayed November 2003

July 2004 November 2004

Glyphosate Imazapyr Glyphosate Imazapyr

Cogongrass 10.5 0.0 25.5 0.8

Hairy Indigo 7.3 3.3 26.8 27.0

Natalgrass 4.0 0.0 7.0 0.8

Passion Vine 5.3 0.0 4.8 3.0

Rustweed 3.3 0.0 2.3 5.3

Torpedograss 0.8 0.0 2.3 0.8

June 1

Imazapyr(Residual Activity)

Sprayed October

Glyphosate

Need to consider timing of

follow-up treatments and planting

June 30

ImazapyrSprayed October

Glyphosate

Reinvasion Follow-upThorough

Site Preparation Needed

Improving Herbicide Effectiveness

•Uptake

Leaf area

Adjuvants (surfactants, etc.)

Root uptake also (must get to soil)

•Translocation to rhizomes

Late summer and fall

Slow kill of leaves

•Break rhizome dormancy (sprouting)

Tillage

Chemical/Hormone

Florida Industrial and Phosphate Research Institute

Improve Herbicide Effectiveness

• Pretreatment (burning, etc.)

• Time of year

• Additives (alone or combinations)

– NIS

– MSO, COC

– Water conditioners

– Nitrogen: UAN, AMS

– Hormones

– Other herbicides (tank mix)

• Competing vegetation + herbicide

More important for low

herbicide rates and non -

optimum conditions

Mowed Burned

Percent Cogongrass Cover November 2006.

Mowed (20 inches tall); Unmowed (40 inches tall)

Sprayed November 7, 2005

Rate (per acre) Mowed Unmowed

Imazapyr 1.0 lb 48 8

Imaz. 0.5 lb + Glyph. 3.0 lb 61 17

Glyphosate 5.0 lb 90 39

Glyph. 5.0 lb + Oust 4 oz 52 39

All treatments with 1% MSO

Peace River Park

Mowing Pre-treatment

Glyphosate + Imazapyr?

•Glyphosate – quicker leaf kill

•Imazapyr – slower leaf kill

•Low rates of imazapyr often as effective as

high rates of glyphosate

•Imazapyr enhances kill with glyphosate

•Glyphosate does not enhance kill with

imazapyr – may even reduce it (quick leaf

kill may reduce translocation)

Burned (wildfire) November 9, 2009

Sprayed December 14, 2009 (8-12 inches tall)

Percent Cover of Cogongrass in 2010

Rate per acre 4/23 5/28 7/29

Imazapyr 0.75 lb 2 2 8

Imazapyr 0.5 lb + Glyphosate 4 lb 5 6 15

Imazapyr 0.375 qt + Glyphosate 3 lb 9 12 22

Glyphosate 3 lb 42 58 78

Glyphosate 4 lb 40 50 73

Untreated check 75 80 95

Alafia River State Park

Imazapyr Enhances Glyphosate

Percent Cogongrass Cover 2010

Not Burned

Sprayed September 28, 2009 (36 inches tall)

Treatment (per acre) 5/28 8/20

0.75 lb Imazapyr 0 1

0.5 lb Imazapyr 1 2

4 lb Glyphosate + 0.5 lb Imazapyr 2 12

2.0% MSO

Hookers Prairie

Glyphosate + Imazapyr?

Imazapyr better

without glyphosate

Percent Cogongrass Cover 2010

Burned August 8, 2009

Sprayed October 8, 2009 (30 inches tall)

Treatment (per acre) July 12 October 10

Glyphosate 4 lb 11 14

Glyphosate 4 lb + Imazapyr 0.5 lb 0 1

Imazapyr 0.5 lb 0 2

Imazapyr 0.75 lb 0 1

Chito Branch

Glyphosate + Imazapyr?

Glyphosate did not enhance imazapyr

Herbicide Additive Effects on Glyphosate Activity

Percent Cogongrass Cover 2010Burned August 8, 2009

Sprayed November 16, 2009 (36 inches tall)

Treatment (per acre) 5/28 7/29

Oust 4.5 oz + Glyphosate 3 lb 2 12

Mat 28 4.5 oz + Glyphosate 3 lb 19 43

Glyphosate 3 lb 16 32

Check 100 100

1% MSO

Chito Branch

Sulfometuron (Oust) enhances glyphosate

Herbicide Additive Effects on Glyphosate Activity

Percent Cover of Cogongrass 2010

Burned November 9, 2009

Sprayed December 14, 2009 (8-12 inches tall)

Rate per acre 4/23 5/28 7/29

Oust 4.5 oz + Glyphosate 3 lb 5 10 11

Imazapyr 0.375 lb + Glyphosate 3 lb 9 12 22

MAT 28 4.5 oz + Glyphosate 3 lb 12 24 43

Glyphosate 3 lb 42 58 78

Glyphosate 4 lb 40 50 73

Untreated check 75 80 95

Imazapyr 0.75 lb 2 2 8

Alafia River State Park

MAT 28 = Method 50 SG Aminocyclopyrachlor

3 lb Glyphosate/acre 3 lb Glyphosate

+ 3.4 oz Sulfometuron

Cogongrass Site Conversion Needed

“Nuke It”

Natives & Exotics

Invading or incomplete kill

Selective Control

• Plant species/genotype

• Chemical type

• Additives (e.g., surfactants)

• Rate (requires calibration)

• Timing (season or growth stage)

• Directed application

Directed Application

• Point and spray (backpack)

• Hack and squirt

• Basal bark

• Ropewick

• Wet glove

Selective

Weed Control

with

Imazapyr

Herbicide

Florida Industrial and Phosphate Research Institute

Boom Spraying

Selective chemical or timing

Height of boom

important

Arsenal 12 oz/acre Oct 2004 Photo Nov 2005

Even low rates of imazapyr

can help control cogongrass

Photo June 2005 Arsenal 24 oz/acre Oct 2004

Some plants quite tolerant of imazapyr

Percent Cover at Fort Green Site in Summer 2005

Sprayed October 2004

Rate

(oz/acre) Cogongrass Pityopsis

12 Arsenal 4.6 30.8

16 Arsenal 0.8 34.6

24 Arsenal 0.0 40.0

12 Plateau 15.7 33.7

16 Plateau 26.7 31.3

24 Plateau 22.5 38.3

Wiregrass, Cogongrass

4-4-07

12 oz Arsenal/acre

11-14 06

Percent Cover August 2006.

Arsenal/Habitat Treatment August 31, 2005

“PR-6” Site

12 oz/acre 16 oz/acre

Species Before After Before After

Andropogon ternarius 0.8 0.5 1.7 1.6

Aristida beyrichiana 18.3 27.0 16.4 13.6

Chamaecrista nictitans 1.9 1.3 1.7 2.7

Cyperus 8.4 0.8 2.2 0.6

Dichanthelium scabriusculum 11.3 0.0 8.4 0.0

Eragrostis spp 0.5 4.1 0.2 1.1

Galactia elliottii 0.0 3.3 0.0 18.4

Imperata cylindrica 28.0 10.3 45.0 4.4

Indigofera hirsuta 0.9 35.6 0.2 17.2

Paspalum notatum 35.3 65.8 35.0 25.5

Pityopsis graminifolia 0.0 0.0 0.2 0.6

Table 12

Percent Cover August 2006.

Arsenal/Habitat Treatment November 31, 2005

“PR-6” Site

12 oz/acre 16 oz/acre

Species Before After Before After

Andropogon ternarius 1.1 1.4 0.9 0.0

Aristida beyrichiana 12.0 7.3 16.6 10.6

Chamaecrista nictitans 3.9 0.2 4.7 1.1

Cyperus 1.7 0.0 0.6 0.2

Dichanthelium scabriusculum 1.3 0.0 7.4 0.3

Eragrostis spp 3.6 2.0 2.2 0.5

Galactia elliottii 0.0 6.3 0.0 6.4

Imperata cylindrica 45.2 6.4 42.7 1.4

Indigofera hirsuta 4.7 15.9 1.7 15.9

Paspalum notatum 41.9 43.0 39.7 33.8

Pityopsis graminifolia 0.2 0.3 1.3 1.3

Table 13

Percent cover before and eight months after treatment

with Arsenal (imazapyr) herbicide

Before (12-7-07) After (8-26-08)

Arsenal (oz/acre) Arsenal (oz/acre)

12 16 24 12 16 24

Aeschynomene americana 0 1 0 10 10 14

Andropogon spp 7 5 9 8 16 20

Aristida stricta 52 59 65 48 50 33

Desmodium triflorum 3 0 1 8 4 6

Imperata cylindrica 43 39 36 19 6 4

Indigofera hirsuta 1 1 2 20 13 10

Paspalum notatum 14 8 0 15 8 3

Pityopisis graminifolia 26 30 31 33 26 27

Table 14

Photo 7-28-08 Habitat 16 oz/A 12-7-07

Selective Rates of Habitat (Imazapyr)

• 12 to 16 oz Habitat per acre

• If 40 gal/acre with backpack and wand (calibrate yourself, use dye)

• 0.3-0.4 oz (9 to 12 ml) per gal with backpack

Imazapyr Tolerant

• Andropogon ternarius

• Aristida stricta

• Eragrostis spp

• Galactia spp

• Helianthus angustifolius

• Liatris spp

• Pityopsis graminifolia

• Pinus elliottii

• Pinus palustris

Imazapyr Effect on Maidencane and Cogongrass

Habitat 16 oz/A 2-5-08

on dormant maidencane

Maidencane Cogongrass

Photo 8-27-08

Percent Cover of Cogongrass and Bahiagrass in June 2004

Burned March 2003, Sprayed December 4, 2003

Arsenal rate “Thin” Cogongrass “Thicker” Cogongrass

(oz/acre) Cogon Bahia Cogon Bahia

0 2.8 51.1 13.3 55.6

12 0.0 42.2 0.0 42.8

16 0.0 28.3 0.0 35.0

24 0.0 23.9 0.6 16.1

32 0.0 10.5 0.0 3.9

Table 15

Percent Cover of Cogongrass and Bahiagrass in August 2005

Burned March 2003, Sprayed January 4, 2005

Arsenal rate “Thin” Cogongrass “Thick” Cogongrass

(oz/acre) Cogon Bahia Cogon Bahia

0 11 87 36 58

12 0 86 2 66

16 0 63 2 29

24 0 31 2 16

12 Plateau 3 87 22 58

Table 16

Check

50% Cogon 8% Cogon

Method (Aminocyclopyrachlor)

Cogon-Bahia

After 2 Months

14% Cogon

4.5 oz 9.0 oz

4-4-07

Arsenal 12 oz/acre

11-14-06

Untreated

Check

Grass Control: Fusilade Herbicide

Cogongrass Control with Fusilade Herbicide

in a Live Oak Planting

Tubeling live oak planted August 12, 2005

Sprayed July 22, 2008

Percent control visually evaluated July 30, 2009

% Control

1.0 oz Fusilade DX per gallon + 0.3% NIS 96

1.0 oz Fusilade DX per gallon + 1.0% MSO 90

Check (90-95% cogongrass cover)

Cogongrass Fusilade 7-22-08

Photo 6-16-09

•Oak + Fusilade

•Oak and directed spray of Round-up + Oust

•Wax myrtle + Fusilade

•Pine + Arsenal, Fusilade, Oust

•Dormant maidencane + Round-up, Arsenal

•Andropogon + Arsenal

•Bahiagrass + Arsenal

Cover Crop + Herbicide

for Cogongrass

Shade and Competition:Woody and Herbaceous Cover Crops

Cogongrass Interaction with Trees

Florida Industrial and Phosphate Research Institute

Dense Canopy

Cogongrass in Sunlight

Wax Myrtle Canopy Effect on Cogongrass

Cogongrass Number of Plots

Cover (%) 2005 2006 2007

75-100 44 15 0

50-74 33 33 1

25-49 15 30 0

10-24 3 12 5

1-9 2 6 28

0 0 1 63

Developing wax myrtle reduced cogongrass with time

Laurel Oak Canopy Effect on Cogongrass

Cogongrass Number of Plots

Cover (%) 2005 2006 2007

74-100 55 42 11

50-74 17 24 19

25-49 3 10 20

10-24 1 0 19

1-9 0 0 6

0 0 0 1

Developing laurel oak reduced cogongrass with time

Fast-Growing Trees & Shrubs

for Cogongrass Control

Wax Myrtle

Laurel Cherry

Black Cherry

Red Mulberry

Cottonwood

Brazilian Pepper

(JUST KIDDING!)