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the glove can then apply the herbicide with total precision <strong>and</strong> little or no run<strong>of</strong>f (Tu et al., 2001). In <strong>field</strong> trials in Southwestern Washington, it was found that when using wipe applications, better knotweed control was observed if the stems were first “topped” (cut) at approximately 3 feet tall than if plants were left intact. After topping the plants, the stems (few leaves or branches remained) were then wiped with a 33% glyphosate mix amended with LI-700. Control was comparable to that found with stem injection <strong>and</strong> wiping results in relatively less herbicide being put into the environment (Tim Miller, Extension Weed Specialist, Washington State University, personal communication). Herbicide: Cut & Fill (From Soll, 2004) Although very slow, this approach also greatly reduces or eliminates drift. This method may be useful in areas where plants are established in particularly sensitive areas or for l<strong>and</strong>owners that are concerned about spraying. After cutting the stem [just below the third node] above the ground, carefully pour or squirt approximately 5ml <strong>of</strong> undiluted herbicide into the stem cavity. [Also apply herbicide to the cross section <strong>of</strong> the cut stem. It is important to due this immediately after cutting as the plant cells will “seal” quickly, preventing the translocation <strong>of</strong> the herbicide (Steven Flint, Invasive Field Steward, Adirondack TNC, personal communication, January 2006)]. Different herbicides allow various concentrations <strong>of</strong> solution to be applied by this method, which will listed on the label. Laboratory squirt bottles have been used to deliver the herbicide. Using a h<strong>and</strong>held a commercial-grade h<strong>and</strong>-held spray bottle to direct herbicide into the stem cavity as well as the cut surface has been shown to be an effective technique as well (Steven Flint, Invasive Field Steward, Adirondack TNC, personal communication). A follow-up foliar or wiping treatment will likely be needed to control new seedlings <strong>and</strong> sprouts. In using this technique, it is very important to have a plan to deal with the cut stems. Because <strong>of</strong> the great propensity for knotweed to root from even very small pieces <strong>of</strong> stem tissue, it is important that the stems are managed in a way as not to provide propagules to start new plants at the control site or create a situation where the stems may be transported <strong>and</strong> set root in a new location. This has been accomplished in many ways, the most common being packing the stems into plastic garbage bags <strong>and</strong> transporting <strong>of</strong>fsite <strong>and</strong> then make ineffective as propagules in many ways including rotting in the bags, drying out on racks or solid pavement, <strong>and</strong> burning. Managing the cut stems can end up being a significant part <strong>of</strong> the overall control effort. Optimal timing for initial cut & fill applications for the Adirondack region in NY was reported as mid-July with a follow-up application in the early fall <strong>of</strong> the same season (Steven Flint, Invasive Field Steward, Adirondack TNC, personal communication, January 2006). Herbicide: Stem Injection (from Oregon TNC, 2005a&b) Direct stem injection involves poking a small hole through both sides <strong>of</strong> a knotweed stem just below the 2nd or 3rd node <strong>and</strong> injecting 1 to 5 ml <strong>of</strong> undiluted glyphosate herbicide 18
into the hollow chamber <strong>of</strong> each stem <strong>of</strong> sufficient size in a knotweed patch. Stems with a large enough diameter (3/4” or larger) can be injected with 5ml <strong>of</strong> glyphosate, smaller stems will receive lesser amounts, depending on the capacity <strong>of</strong> the hollow chamber. Depending on the characteristics <strong>of</strong> a st<strong>and</strong>, many stems may be too small to accept glyphosate injection. [Wipe or foliar spray applications can be options for the stems too small to receive injection.] Stem injection treatments were administered using a device acquired from JK International Injection Tools (www.jkinjectiontools.com). The injection tools can hold approximately 420 ml <strong>of</strong> glyphosate in the canister. A measured dose, between 1-7mls, can be delivered by pulling the trigger once the needle is inserted into the stem <strong>of</strong> a plant (Figure 2.0). For the most part we set our tools to deliver 5mls per injection, with the exception <strong>of</strong> sites where the amount <strong>of</strong> knotweed was so great that we would approach the legal limit <strong>of</strong> 7.5 liters per acre if the 5ml amount was used. In those cases we dropped the amount per stem down to 3ml, or utilized foliar spray as described above. Figure 5. Stem injection (Oregon TNC, 2005b) After two years <strong>of</strong> treatment in our controlled experiment, we found no statistically significant benefit to using 5ml vs. 3ml or 1.5 ml per stem, or to supplementing stem injection <strong>of</strong> 5ml with foliar applied glyphosate. That said, the 5ml+foliar spray had the highest level <strong>of</strong> control for every variable except for re-growth outside the main patch area. As a result, because living patches are a threat to downstream habitat we recommend that <strong>field</strong> control programs take a conservative approach <strong>and</strong> incorporate supplemental foliar spray into their control regimen whenever it is legal or feasible. Because we did not compare supplemental spraying <strong>of</strong> the three dose levels in the controlled portion <strong>of</strong> the experiment, we can not specifically address whether the lower 19
Page 1 and 2: A review o
Page 3 and 4: Preface This document is a product
Page 5 and 6: differ, but they are commonly lumpe
Page 7 and 8: Roadside ditches, irrigation canals
Page 9 and 10: edge. The farmer said that he occas
Page 11 and 12: landscape planning
Page 13 and 14: in the literature,
Page 15 and 16: If you do try and
Page 17 and 18: area and securing
Page 19: A standard mixing
Page 23 and 24: Combining different control methods
Page 25 and 26: additional invasive species. Coveri
Page 27 and 28: Conclusions Patches outside the 100
Page 29 and 30: References Boquet River Association
Page 31 and 32: Appendix A: Knotweed management pro

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