Research on Lygodium microphyllum

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Research on Lygodium microphyllum at the Center
for Aquatic and Invasive Plants
Jeff Hutchinson and Ken Langeland
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Weed Science
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Research Projects

• Herbicide translocation
• Greenhouse herbicide screening
• Field herbicide screening - Ground - Aerial
• Herbicide resistance to ALS inhibitors

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14C Herbicidetranslocation
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14C Herbicides

• Glyphosate (Rodeo)0.90 kg a.e./ha (0.80 lbs
  a.e./acre)
• Metsulfuron methyl (Escort XP)0.06 kg a.i./ha
  (0.05 lbs a.i./acre)
• Triclopyr (Renovate 3) 0.53 kg a.e./ha (0.50 lbs
  a.e./acre)

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5 plants per treatment Repeated twice
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Glyphosate
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Metsulfuron methyl
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Triclopyr
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(No Transcript)
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Greenhouse Herbicide Screening
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Herbicides Tested(rates)

• Glyphosate(1.70 kg a.e.)
• Metsulfuron methyl(0.04 kg a.i.)
• Imazapyr(0.68 kg a.e.)
• Imazapic(0.09 kg a.e.)

• Triclopyr(2.70 kg a.e.)
• Imazamox(0.02 kg a.e.)
• Penoxsulam(0.02 kg a.e.)
• Quinclorac(0.68 kg a.e.)

15 plants per treatment Repeated twice
Rates were at maximum label rate
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Visual Observations
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Dry Weight Biomass(post-treatment)
Herbicide Dry Weight (g)
Glyphosate 0.13
Metsulfuron methyl 0.61
Imazapyr 4.07
Imazapic 3.58
Quinclorac 8.01
Penoxsulam 7.71
Imazamox 10.37
Triclopyr 0.00
Control 9.68
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3rd Trail 6 months post-trt
Herbicide L. Microphyllum Dry weight (g) Native Plants Dry weight (g) Species Richness
Glyphosate 0.52 5.50 5.27
Metsulfuron m. 2.08 4.52 4.93
Imazapyr 1.78 0.64 1.40
Imazapic 0.69 1.73 1.87
Quinclorac 6.33 4.05 3.67
Penoxsulam 10.00 2.07 2.93
Imazamox 11.07 1.43 3.20
Triclopyr 0.35 9.06 6.33
Control 13.41 2.22 3.67
15 plants per treatment No replication
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Imazamox
Imazapyr
Triclopyr
Penoxsulam
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Additional Greenhouse Screenings

• Imazamox (Clearcast) increased rates
• Aminopyralid (Milestone)
• Fluroxypyr (Vista)
• Flumioxazin (Sureguard)
• Bispyribac-sodium (Regiment)

Rates Max, 1/2, 1/4, and 1/8 label rate 4
Plants per treatment First screening completed
2006 Second screening scheduled for 2007
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Visual Observations (2.5 months)
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Dry Weight Biomass
Herbicide Rate (kg a.e.) Dry Weight (g)
Imazamox 0.06 2.27
Imazamox 0.12 0.35
Imazamox 0.24 0.03
Imazamox 0.48 0.01
Fluroxypyr 5.25 6.34
Fluroxypyr 10.5 8.63
Fluroxypyr 21.0 3.51
Fluroxypyr 42.0 1.00
Aminopyralid 0.015 2.09
Aminopyralid 0.03 5.35
Aminopyralid 0.06 0.48
Aminopyralid 0.12 3.84
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Field Herbicide Screening
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Ground treatments
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Field Sites

• Balm Scrub (Hillsborough Co.)
• Jonathan Dickinson SP (Martin Co.)
• Pacific Tomato Growers (Collier Co.)
• Loxahatchee NWR (Palm Beach Co.)
• Highlands Hammock SP (Highlands Co.)
• Indian River Comm. College (St. Lucie Co.)
• Lakeland Artificial Wetland System (Polk Co.)

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Herbicide Rates

• Single Herbicides
• Glyphosate 2.0
• Glyphosate 4.0
• Metsulfuron methyl 2 oz/100 gallons
• Metsulfuron methyl 4 oz/100 gallons
• Triclopyr 2.0
• Imazapic 1.5

• Tank Mixes
• Metsulfuron 2oz Glyphosate 2
• Metsulfuron 2oz Triclopyr 2
• Metsulfuron 2oz Imazapic 1.5
• Glyphosate 2 Triclopyr 2
• Glyphosate 2 Imazapic 1.5
• Glyphosate 1 Triclopyr 1 Metsulfuron 1oz
• Control

13 treatments per site 10 meter cover transect
lines
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Project Design
Native Plants
10 meters
Lygodium
Native plants separated to species
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Monitoring (pre-treat, 6 months, 1 year, and 2
years)

• Pre-treatment

• 6 months
• Post-treatment

Escort XP 2 0unces / 100 gallons water
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Results (6 months)
Herbicide Change L. microphyllum Change Native Plants Change Species Richness
Glyphosate 2 - 84.1 - 56.9 2.8
Metsulfuron 2 oz - 74.6 - 31.6 2.5
Triclopyr 2 - 91.5 - 31.4 - 5.1
Imazapic 1.5 - 82.8 - 71.5 - 48.5
Metsulfuron Glyphosate - 89.1 - 53.8 - 27.3
Metsulfuron Triclopyr - 91.5 - 43.6 - 24.3
Glyphosate Imazapic - 92.4 - 55.3 - 30.1
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Preliminary Conclusions

• No significant difference among treatments -
  Reduction of L. microphyllum ranged from 74.6
  (metsulfuron 2oz) to 94.2 (metsulfuron
  imazapic)
• Glyphosate (4) and imazapic resulted in
  significant impacts to non-target plants relative
  to the other treatments at 66.2 and 71.5
  reduction, respectively.
• Species richness decline in all plots except
  glyphosate (2) and metsulfuron (2oz)

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Non-Target Damage

• Expect non-target damage- Depends on Lygodium
  density
• Native ferns
• Rare plants

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Initial Treatment
Follow-up Treatments
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Aerial treatments
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Loxahatchee NWR
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Pre-monitoring
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Treatment Aerial Ground Ground
Treatment Year 1 Year 2 Year 3 Year 4
Treatment ? ?
Metsulfuron (2 oz) X X X Final Evaluation
Metsulfuron (4 oz) X Final Evaluation
Metsulfuron (4 oz) X X Final Evaluation
Metsulfuron (4 oz) X X X Final Evaluation
Glyphosate (3.75 pints) X X Final Evaluation
Glyphosate (3.75 pints) X X X Final Evaluation
Glyphosate (7.5 pints) X X Final Evaluation
Glyphosate (7.5 pints) X X X Final Evaluation
Control Final Evaluation
Five tree islands per treatment
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Loxahatchee NWRLygodium microphyllum
Pre-treatment Pre-treatment 1 Year Post Trt 1 Year Post Trt
Treatment Mean S.E. Mean S.E. Change
Escort 2 oz 67.33 4.40 0.38 0.14 - 99.44
Escort 4 oz 59.46 2.62 1.47 0.48 - 97.53
Rodeo 3.75 pt. 66.50 3.64 7.00 1.62 - 89.47
Rodeo 7.50 pt. 69.72 2.35 8.07 1.31 - 88.43
Control 46.01 5.14 56.97 4.79 23.82
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Swamp fern Cinnamon fern Virginia chain fern Royal fern Wild grape Green brier
Escort (2 oz) Pre 22.4 1.1 0.4 0.8 8.6 10.4
Escort (2 oz) 1 Yr 1.5 0.1 lt0.1 0.0 21.2 0.9
Escort (2 oz) Change -93.5 -90.2 -94.8 -100.0 147.4 -91.7
Escort (4 oz) Pre 26.3 0.7 0.5 1.3 9.3 14.4
Escort (4 oz) 1 Yr 3.1 0.4 0.3 0.3 23.0 0.5
Escort (4 oz) Change -88.4 -45.1 -44.3 -77.3 148.5 -96.5
Glyphos (3.75 pt) Pre 32.7 0.8 0.2 1.8 11.1 19.0
Glyphos (3.75 pt) 1 Yr 6.3 2.9 2.4 0.4 12.8 0.5
Glyphos (3.75 pt) Change -80.6 280.5 1523.3 -78.2 15.0 -97.6
Glyphos (7.5 pt) Pre 25.8 1.1 0.8 1.8 10.8 14.1
Glyphos (7.5 pt) 1 Yr 2.3 4.3 2.4 0.4 22.1 0.3
Glyphos (7.5 pt) Change -90.9 291.9 183.0 -80.7 105.8 -98.2
Control Pre 33.3 1.3 1.8 0.4 7.2 12.0
Control 1 Yr 38.3 9.5 0.2 0.9 2.6 4.9
Control Change 15.0 635.7 -88.1 112.6 -63.8 -56.5
Ground Cover
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Shrubs / Trees
Survival Survival Survival Survival
Swamp bay Dahoon holly Wax myrtle Myrsine
Metsulfuron (2 oz) 80.8 82.4 71.2 6.7
Metsulfuron (4 oz) 89.7 79.1 80.5 0.0
Glyphosate 3.75 pt 54.0 85.4 32.0 100.0
Glyphosate 7.5 pt 24.5 52.2 20.8 66.7
Control 100.0 100.0 70.4 100.0
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One-year Post-treatment (Dec 2006)
Metsulfuron methyl 2oz/20gal
Glyphosate 3 ¾ pints/20gal
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Herbicide resistance to ALS Inhibitors
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Treatment of gametophytes

• ALS gene is nuclear inherited.
• Resistant plants in a population are
  approximately 1 in 1-3 million.
• Easier to treat 1 million gametophytes than 1
  million plants.

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Fertile leaflet
Spore
Mature plant
Fern Life Cycle
Sporophyte
Gametophyte
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Metsulfuron Methyl Rates

• 1.7 g a.i. (0.10 oz)
• 4.3 g a.i. (0.25 oz)
• 8.5 g a.i. (0.50 oz)
• 17.0 g a.i. (1.00 oz)
• 34.0 g a.i. (2.00 oz)
• 68.0 g a.i. (4.00 oz)
• Surfactant only
• Control

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Estimated number of spores using Sedgewick Rafter
chamberDiluted sample to obtain ca. 100,000
spores per samplePlaced spores on agar plates
with macro-nutrients, micro-nutrients, and iron.
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Gametophyte Survival Rate
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Gametophytes at different treatment rates
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Testing for Resistance

• Initial herbicide screening of millions of spores
  and gametophytes
• Allow gametophyte development/fertilization and
  re-treat tolerant spores (2nd generation).
• Spray tolerant plants.
• Use ALS bioassay (test for levels of differential
  accumulation of acetoin between treated and
  untreated plants)

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Germination Rates
Site Spore Age (months) Germination ()
JDSP (1) 3.0 47
Highlands Hammock 7.3 95
Immokalee PTG 7.8 55
Fisheating Creek WMA 8.3 79
East Orlando 18.0 96
Loxahatchee NWR (1) 20.8 27
Loxahatchee NWR (2) 20.8 8
JDSP (2) 35.3 10
JDSP (3) 35.3 84
DuPuis 95.0 2
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Other Projects

• Screen glyphosate, metsulfuron methyl, and
  triclopyr at lower rates in the greenhouse
• Spore germination rates in treated vs. untreated
  sites
• Evaluation of metsulfuron methyl on selected
  non-target plants
• Evaluation of aerial and ground herbicide
  treatments on L. microphyllum at DuPuis and
  Allapattah Flats

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Highlands Hammock State Park Soil Samples

• No Lygodium

Treated Lygodium
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Acknowledgements

• Florida DEP
• SFWMD
• USFWS
• SJRWMD
• FLEPPC

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Questions