Herbicide foam wiped on leaves of small weed tree.
Weed tree is dead approximately 20 days later.
With wipe applications, a device is used to “physically wipe” an herbicide onto a plant. Johnson et al. 2012 (link). Because these applications are precise and controlled and generally made only to a portion of the plant, the herbicide concentration in the spray solution typically used is higher than with other foliar applications. Green et al. 2003 (link). For example, for AquaMaster (an herbicide containing glyphosate), the label recommends solutions having from 18% active ingredient to 54% active ingredient for wiper applicators.
The herbicide wiping method can be used very effectively with the foam herbicide dispenser from Green Shoots (link). The photos above show an application of foam herbicide I made with the Green Shoots Foam Herbicide Dispenser to a weed tree (maple seedling) located in a planting bed.
The herbicide solution used in this case had approximately 20% active ingredient (i.e., a low concentration for the typical wiper applications). Moreover, I applied very small amounts of herbicide foam to the leaves. Nonetheless, it appears the woody weed completely died. We will keep testing less concentrated solutions in order to minimize herbicide usage as much as possible.
Wiping with an herbicide foam has real advantages. The wiped foam herbicide is much less prone to drip. Traditional herbicide wipers work with sponges or canvas which can become saturated and drip. Moreover, clumps of herbicide foam stick better to plant surfaces than large herbicide droplets from a standard wiper system. Finally, with foam herbicide wiping, there are no sponges or canvas cloths that may become contaminated with dirt and dust or that need to be cleaned afterwards.
We will keep testing wipe application techniques on various plants and will post blog updates and videos.
Green Shoots Foam Herbicide Dispenser
John Lampe of Green Shoots recently gave a presentation on the Rhizome Injection Method for Controlling Invasive Knotweed (link) at the University of Michigan where the Midwest-Great Lakes Chapter of the Society for Ecological Restoration held its 2012 chapter meeting.
We will start some trials later this summer and autumn in which we inject herbicide into the rhizomes of non-native phragmites. These trials will mostly be done on Minnesota Department of Transportation right-of-ways. We will use the Green Shoots Rhizome Injector protoype. This is the same tool we are currently trialing on Japanese knotweed. The rhizome of phragmites is hollow like the knotweed rhizome. It also consists of internodes and nodes. A septum separates each internode. Although the phragmites stem and rhizome are a little smaller in diameter the the knotweed stem and rhizome, injection seems to work pretty well. Here are some photos showing views of the rhizome and the proposed technique.
Phragmites stand in Minnesota Department of Transportation right-of-way.
Injection into phragmites rhizome through hollow stem.
Phragmites stem through which rhizome was injected.
Length-wise cross-section of phragmites rhizome. Note septum separating each internode.
Length-wise cross-section of phragmites rhizome showing how needle of injector could be inserted.
In our last couple posts you saw the rhizome injector system that we have been experimenting with. We did applications throughout the winter and early spring. The injections were through the dead hollow stems. We cut the stems at ground level and inserted the needle down into the rhizome. A few weeks ago, I noticed the shoot clumps were starting to send up aerial shoots. I was concerned that the herbicide might not be having an effect. However, glyphosate is slow-acting, so I kept reminding myself to be patient.
We are finally starting to see results. They are encouraging. Here are photos of several of the treated stems.
Knotweed plants dying: two brown ones have collapsed and one in middle is showing effects of herbicide. Note hollow stem to which injection was done at bottom of photo.
Rhizome Injection to cut hollow stem in middle of photo. One dead stem and another showing herbicide injury.
Rhizome Injection on March 23, 2012. Brown dead plant showing effects of injection. Injection was through hollow stems that show some coloration from dye.
Healthy untreated knotweed stems nearby.
We have continued testing prototypes of our new rhizome injector. This product will be used to treat invasive plants such as Japanese knotweed (Fallopia japonica) with herbicide. We
Injection into Rhizome through hollow stalk of dead aerial shoot
access the underground rhizomes (which remain alive year-round) through the hollow core of the dead aerial shoots. We inject glyhposate herbicide (Aquamaster, 54% active ingredient) into the rhizome through the hollow core. There are several potential advantages of this technique: by injecting into the heart of the rhizome, treatments should be more effective; the plant can be treated at many different times of the year; less herbicide may be necessary to achieve good results; problems associated with disposing of green aerial shoots (which can easily sprout when contacting soil) can be avoided; and fewer stems will need to be treated while maintaining effectiveness.
How can effectiveness be maintained while treating fewer stems? Current techniques for killing knotweed require injection into each living green stem for the treatment to be effective. With this new technique developed at Green Shoots, it is believed that by
Two treated stumps with winter bud
injecting the herbicide deep into the rhizome the herbicide will translocate further within the rhizome to multiple buds (from which stems gow) such as the reddish winter bud shown peeping up through the ground in the photo at left. Each crown has multiple buds. By injecting the herbicide into the rhizome, each of these buds should be killed and thus fewer injections should be necessary.
We will keep you posted on the results as the season progresses.
This video shows me taking down a large buckthorn tree. I am using a chainsaw because this tree must be
Cutting Back A Big Buckthorn
about ten inches in diameter and probably 80 to 100 years old. After cutting off the tree and leaving a stump, I am applying foam herbicide using a dispenser being developed by Green Shoots.
We are testing prototypes of a new rhizome injection system for use on plants such as Japanese knotweed (Fallopia japonica).
We have done preliminary tests with the rhizome injector. A key aspect of the system is that aerial shoots do not have to be
FIG. 1 - Injection through hollow of dead Japanese knotweed shoot into rhizome
living in order to make an injection. (as this injection in winter shows!) The injection is into the “green node” which is underground in the rhizome.
FIG. 2 - Cross-section of Japanese knotweed rhizome
We have had encouraging preliminary results but need to have more rigorous testing especially with outside experts. Potential advantages of the method include:
- injections could be made when the aerial shoots are dead – lessening worries about disposal of living plant parts;
- injections are directly into the rhizome – the part of the plant that needs to be killed for long-term success;
- amounts of herbicide used can potentially be less – We have thus far used approximately 2 ml per plant (Aquamaster (54% ai glyphosate diluted slightly with 0.15% colorant);
- injections could be made at times of the year that are less busy; and
- it may be possible (not confirmed) that fewer aerial shoots can be treated if injection is deep enough into the rhizome and herbicide then translocates to a greater number of shoots.
As of January 30, 2012, we are seeking six testers who have:
- treated Japanese knotweed before;
- used injection and foliar methods;
- access to test areas with mature Japanese knotweed stands;
- the ability to make at least 3 applications at different times of the year (including spring (before aerial shoots sprout), late summer, and late fall (after die-back of aerial shoots); and
- the ability to complete a short test summary with photos.
There will be no cost to the testers and testers can keep the prototype. If you are interested in finding out more, please contact me at john at greenshootsonline dot com.
This blog offers news about Green Shoots. Green Shoots is a company that develops and offers products to control invasive plants.
Invasive plants such as kudzu, Japanese knotweed, buckthorn, and Brazilian pepper tree are devastating native ecosystems. Green Shoots offers a better way to control them.
Our precision herbicide dispensers (patents pending) apply a concentrated herbicide foam under ultra low pressure. The foam herbicide sticks tenaciously and dries more slowly on the targeted weed. This increases absorption of the herbicide into the weed. In addition, our system dramatically reduces drift, overspray, and drippage.
Not only can our products help control invasive species, they can also help reduce harm to desirable plants and the broader environment. Hence, our credo: control invasive species – restore native balance.