This was a presentation at the 2014 Upper Midwest Invasive Species Conference. It discusses the use of a low drift, foam herbicide system, a novel technique for controlling knotweeds and other plants. The system was developed by Green Shoots, LLC, http://www.greenshootsonline.com/newsite/default.aspx.
6. Non-Chemical Control
โข Not practical except with small infestations
โข Danger of vegetative spread
โข See King County, Best Management Practices
(2008)
17. Stem Injection
โข Use hypodermic or special injector
โข Inject up to 5 ml into stem
โข Between 1st and 2nd node above ground
18. Stem Injection
โข Advantages:
โ Precision
โ No stem disposal
โ Avg control: 91-100 % (Prather + Miller 2009)
โข Disadvantages:
โ Time-consuming
โ Identifying treated stems
โ Difficulty in treating small stems
โ Non-target injury: 26% (Miller 2005)
โ And . . .
19. Biggest Disadvantage of Stem Injection
โข Requires 5 ml of herbicide per aerial shoot
โ Equivalent to cut surface application on 10 to 15
inch woody stem. AquaMaster Label.
โข May explain 26% non-target injury found by
Miller.
20. Cut Stem
โข Cut stem 5 to 10 inches off ground
โข Immediately pour up to 3 ml into hollow of
stem
22. Cut Stem
โข Advantages:
โ Low cost equipment
โ Control? (Miller did not test)
โข Disadvantages:
โ Time-consuming
โ Disposal of green aerial shoots
โ Amount of herbicide used
23. Foliar
โข Advantages
โ Fastest application method
โ Decent control: 81%. (Miller 2005)
โ No disposal issues
โ Less herbicide used
โข Disadvantages
โ Off-target harm: Avg. injury: 68%. (Miller 2005)
โ Hard to treat tall plants
24. Follow-Up Applications
โข Washington State Dept. Agriculture:
โ Data show โsignificant decrease in knotweed
following six years of annual treatments.
โ However, knotweed is still present at each
monitoring site.โ (Statewide Knotweed Control
Program; 2010 Progress Report)
25. How Can Methods Be Improved?
โข Reduce repeat applications
โข Reduce quantity of herbicide used
โข Reduce off-target harm
47. Approximately 11 months after single
treatment
Native
Pilewort
dominates
now
Scattered
knotweed
48. Our Mission: To
recognize
opportunities and
provide leadership
to make our region
a vibrant, place-based
model for the
nation.
563-864-7112; www.northeastiowarcd.org
49. Use on Japanese
knotweed along
Paint Creek in
Northeast Iowa
50. Report from Richard Kittelson from the Northeast Resource,
Conservation and Development Organization:
โข โWe had an excellent result at the Hardees
site, I'd say 80-90% effective. I just foam
treated the resprouts on 9/30. The resprouts
covered aprox. 10% of the area sprayed last
year. It took 1/2 liter of mix.โ
โข โThe west bank that had been 95% stem
injected had more resprouts, aprox. 25% of the
area. That side took 1 liter of mix to treat.โ
51. Testing By Dr. Timothy Miller at
Washington State University
โข Late Summer 2014
โข Comparing Spray and Foam Herbicide
โข Bohemian and Himalayan knotweed
โข Herbicides:
โ Rodeo (glyphosate)
โ Habitat (imazapyr)
โ Perspective (aminocyclopyrachlor)
โ Milestone (aminopyralid)
52. WSU testing (con.)
โข Used 1 liter per plot with foam herbicide
โข Used 2 liters per plot with spray
โข I.e., using ยฝ as much foam herbicide as spray.
โข Plots (I believe are 20 by 20 feet)
โข Research is not funded by Green Shoots; we
did provide WSU with a dispenser
53. Early WSU Results โ Percent Control
Determined by Defoliation
Type 2 WAT 4 WAT
Foam 51% avg. 69% avg.
Spray 46 avg. 66 avg.
Note: Averages across all herbicides used and two species of knotweed.
54. Why Might Foam Work Better?
โข Foam is well suited for low volume
applications
โ Less dripping
โ Slower drying of herbicide
โ Foam clings tenaciously to foliage
โข More surfactant used
โข Key Benefit: Virtually eliminates drift
55. 55
Green Shoots
John Lampe โ contact:
โขjohn@greenshootsonline.com
โข651-245-4682 (cell)
Website:
www.greenshootsonline.com
โขEmail or call for copy of
presentation