Injection of Herbicides intoRhizomes of Knotweeds and Other          Invasive Species       Upper Midwest Invasive Species...
Knotweed – Why Control?• It is listed by the World Conservation Union as  one of the worlds 100 worst invasive species.• T...
Outline of Talk• Background on Knotweed• Current Chemical Control Methods• How Can Our Methods be Improved to:  – Reduce q...
Common Species of Knotweed• Japanese knotweed (Polygonum cuspidatum)• Giant knotweed (Polygonum sachalinense)• Bohemian kn...
IdentificationGood source: Prather TS, Miller TW, RobinsSS, Knotweed shrubs: identification, biology, andmanagement, Pacif...
Knotweed Colony
Knotweed Leaves                                           • Dark green leaves                                           • ...
Knotweed Stems - Young
Knotweed Stem - Dry                               • Hollow internodes                               • Septum separating   ...
Knotweed RhizomeRhizome
Knotweed Spreads by• Rhizome extension – up to 6 to 8 feet a year• Distribution of plant parts  – Rhizome pieces – as smal...
Knotweed Badness• Riparian areas especially vulnerable• Out-compete other plants => monoculture  – Loss of trees  – Change...
Knotweed Monoculture       Photo Credit: Justin Knabe, Minnesota DOT
Knotweed Rhizome Extension           Photo Credit: Popplewell Associates, York, UK
Knotweed Rhizome Extension
Knotweed Rhizome Extension
Non-Chemical Control• Not practical except with small infestations• Danger of vegetative spread• See King County, Best Man...
Chemical Control Methods• Foliar• Stem injection• Cut stem
Key Herbicides• Glyphosate – aquatic label• Triclopyr – aquatic label; only foliar• Imazapyr – aquatic label; only foliar
Knotweed Rhizome Tough to Kill!Key Problem: older parts of rhizome and dormantbuds are weak sinks. (Bashtanova et al. 2009.)
Knotweed Rhizome – Tough to Kill!
Foliar• Advantages  – Fastest application method  – Decent control: 81%. (Miller 2005)• Disadvantages  – Off-target harm: ...
Stem Injection
Stem Injection• Use hypodermic or special injector• Inject up to 5 ml into stem• Between 1st and 2nd node above ground
Stem Injection• Advantages  – Precision  – No stem disposal  – Efficacy; Avg control: 88% (Miller 2005)• Disadvantages  – ...
Biggest Disadvantage of Stem Injection• Requires 5 ml of herbicide per aerial shoot  – Equivalent to frill application on ...
Cut Stem• Cut stem 5 to 10 inches off ground• Immediately pour up to 3 ml into hollow of  stem
Pouring Herbicide into Cut Stem
Cut Stem• Advantages  – Low cost equipment  – Control? (Miller did not test)• Disadvantages  – Time-consuming  – Disposal ...
Stem Wipe• Inconsistent Results (Miller 2005)
Follow-Up Applications• Washington State Dept Agriculture:  – Data show “significant decrease in knotweed    following six...
How Can Methods Be Improved?• Reduce repeat applications• Reduce quantity of herbicide used• Reduce off-target harm
We Have BeenTrying Several Methods
Rhizome Injection
Rhizome and Roots
Rhizome Injection          Needle reaches to          below-ground          Internode
Herbicide Used• AquaMaster – glyphosate; 54% a.i.• Dose at 2ml• Well below AquaMaster label rate for hollow  stem injectio...
Inserting Needle into Cut, Dead Stem
Injecting into Rhizome   through Cut Stem
Inserting Needle into Bent Live Stem
Results?
Ongoing Rhizome Injections• Winter and early spring injections did not  produce results• Late spring injections show promi...
Other New Methods Being Explored
Cut, Bend, and . . .
Treat with Foam Herbicide
Munch, Bend, and . . .
Treat with Foam
Tromp, Wait, and . .
Treat Regrowth with Foliar Applied
Low Volume Foam Herbicide
Bend and Immediately Treat . . .
Stems and . . .
Foliage
Potential Advantages of Foliar                 Methods• Not treating tall plants – reduces off-target  harm• Treating with...
Rhizome Injection Methods• Less time consuming• Less herbicide• Injecting into rhizome – will this improve  treatment succ...
Bent Stem Wiping Methods• Exposing vascular tissue• Foam herbicide sticks to stem• Uses a lot less herbicide
Green ShootsJohn Lampe – contact:• john@greenshootsonline.com• 651-245-4682 (cell)Website:www.greenshootsonline.com• Email...
Injection of Herbicides into Rhizomes of Knotweeds and Other Invasive Species
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Injection of Herbicides into Rhizomes of Knotweeds and Other Invasive Species

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We ran trials on this method for a few years as did other organizations and individuals. Ultimately, we did not find its efficacy to outweigh the labor involved. Therefore, Green Shoots decided not to launch the product. We have however had real success with foliar applications using our Green Shoots Foam Herbicide Dispenser. John Lampe gave a presentation on that system at the 2014 Upper Midwest Invasive Species Conference: http://www.slideshare.net/johnlampe/how-to-kill-i.

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Injection of Herbicides into Rhizomes of Knotweeds and Other Invasive Species

  1. 1. Injection of Herbicides intoRhizomes of Knotweeds and Other Invasive Species Upper Midwest Invasive Species Conference October 29-31 La Crosse, Wisconsin John Lampe Green Shoots, LLC Saint Paul, Minnesota 1
  2. 2. Knotweed – Why Control?• It is listed by the World Conservation Union as one of the worlds 100 worst invasive species.• This is not precise ranking but does show recognition of how problematic species is.
  3. 3. Outline of Talk• Background on Knotweed• Current Chemical Control Methods• How Can Our Methods be Improved to: – Reduce quantity of herbicide used – Reduce off-target harm
  4. 4. Common Species of Knotweed• Japanese knotweed (Polygonum cuspidatum)• Giant knotweed (Polygonum sachalinense)• Bohemian knotweed (Polygonum x bohemicum) – hybrid
  5. 5. IdentificationGood source: Prather TS, Miller TW, RobinsSS, Knotweed shrubs: identification, biology, andmanagement, Pacific Northwest ExtensionPublication 2009
  6. 6. Knotweed Colony
  7. 7. Knotweed Leaves • Dark green leaves • Un-toothed • alternatePhoto Credit: Steve Manning, Invasive Plant Control, Bugwood.com
  8. 8. Knotweed Stems - Young
  9. 9. Knotweed Stem - Dry • Hollow internodes • Septum separating • Up to 2 in. dia. Photo Credit: James H. Miller, USDA Forest Service, Bugwood.com
  10. 10. Knotweed RhizomeRhizome
  11. 11. Knotweed Spreads by• Rhizome extension – up to 6 to 8 feet a year• Distribution of plant parts – Rhizome pieces – as small as 0.7 g (Brock 1992) – Node pieces• Seeds – not major source in WA. (Miller 2005)
  12. 12. Knotweed Badness• Riparian areas especially vulnerable• Out-compete other plants => monoculture – Loss of trees – Changes in soil fertility – Erosion along streambeds and stream banks
  13. 13. Knotweed Monoculture Photo Credit: Justin Knabe, Minnesota DOT
  14. 14. Knotweed Rhizome Extension Photo Credit: Popplewell Associates, York, UK
  15. 15. Knotweed Rhizome Extension
  16. 16. Knotweed Rhizome Extension
  17. 17. Non-Chemical Control• Not practical except with small infestations• Danger of vegetative spread• See King County, Best Management Practices (2008)
  18. 18. Chemical Control Methods• Foliar• Stem injection• Cut stem
  19. 19. Key Herbicides• Glyphosate – aquatic label• Triclopyr – aquatic label; only foliar• Imazapyr – aquatic label; only foliar
  20. 20. Knotweed Rhizome Tough to Kill!Key Problem: older parts of rhizome and dormantbuds are weak sinks. (Bashtanova et al. 2009.)
  21. 21. Knotweed Rhizome – Tough to Kill!
  22. 22. Foliar• Advantages – Fastest application method – Decent control: 81%. (Miller 2005)• Disadvantages – Off-target harm: Avg. injury: 68%. (Miller 2005) – Hard to treat tall plants
  23. 23. Stem Injection
  24. 24. Stem Injection• Use hypodermic or special injector• Inject up to 5 ml into stem• Between 1st and 2nd node above ground
  25. 25. Stem Injection• Advantages – Precision – No stem disposal – Efficacy; Avg control: 88% (Miller 2005)• Disadvantages – Time-consuming – Id of treated stems – Non-target injury: 26% (Miller 2005)
  26. 26. Biggest Disadvantage of Stem Injection• Requires 5 ml of herbicide per aerial shoot – Equivalent to frill application on 10 to 15 inch woody stem. AquaMaster Label.• Aerial shoot density averages about 9 stems/m2. Brock 2007.• 45 ml of 54% a.i. glyphosate per square meter.• May explain 26% non-target injury found by Miller.
  27. 27. Cut Stem• Cut stem 5 to 10 inches off ground• Immediately pour up to 3 ml into hollow of stem
  28. 28. Pouring Herbicide into Cut Stem
  29. 29. Cut Stem• Advantages – Low cost equipment – Control? (Miller did not test)• Disadvantages – Time-consuming – Disposal of green aerial shoots – Amount of herbicide used
  30. 30. Stem Wipe• Inconsistent Results (Miller 2005)
  31. 31. Follow-Up Applications• Washington State Dept Agriculture: – Data show “significant decrease in knotweed following six years of annual treatments. – However, knotweed is still present at each monitoring site.” (Statewide Knotweed Control Program; 2010 Progress Report)
  32. 32. How Can Methods Be Improved?• Reduce repeat applications• Reduce quantity of herbicide used• Reduce off-target harm
  33. 33. We Have BeenTrying Several Methods
  34. 34. Rhizome Injection
  35. 35. Rhizome and Roots
  36. 36. Rhizome Injection Needle reaches to below-ground Internode
  37. 37. Herbicide Used• AquaMaster – glyphosate; 54% a.i.• Dose at 2ml• Well below AquaMaster label rate for hollow stem injections: 5 ml
  38. 38. Inserting Needle into Cut, Dead Stem
  39. 39. Injecting into Rhizome through Cut Stem
  40. 40. Inserting Needle into Bent Live Stem
  41. 41. Results?
  42. 42. Ongoing Rhizome Injections• Winter and early spring injections did not produce results• Late spring injections show promise• Currently doing tests – late summer and Fall
  43. 43. Other New Methods Being Explored
  44. 44. Cut, Bend, and . . .
  45. 45. Treat with Foam Herbicide
  46. 46. Munch, Bend, and . . .
  47. 47. Treat with Foam
  48. 48. Tromp, Wait, and . .
  49. 49. Treat Regrowth with Foliar Applied
  50. 50. Low Volume Foam Herbicide
  51. 51. Bend and Immediately Treat . . .
  52. 52. Stems and . . .
  53. 53. Foliage
  54. 54. Potential Advantages of Foliar Methods• Not treating tall plants – reduces off-target harm• Treating with Foam Herbicide – Improves adhesion – Reduces drift• Late season – should improve treatment success
  55. 55. Rhizome Injection Methods• Less time consuming• Less herbicide• Injecting into rhizome – will this improve treatment success?
  56. 56. Bent Stem Wiping Methods• Exposing vascular tissue• Foam herbicide sticks to stem• Uses a lot less herbicide
  57. 57. Green ShootsJohn Lampe – contact:• john@greenshootsonline.com• 651-245-4682 (cell)Website:www.greenshootsonline.com• Email or call for copy of presentation 58

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