invasive weed management - bugwoodcloud · some principles and guidelines •we are surrounded by...
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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!)