In New Jersey
Larry Murrell
Highlights
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• Stem injection can be done for 10 months of the year in NJ
• Injection can be improved using pre-drilled holes in stems
-- stems of all sizes can be treated in this way • Injection can be done from 6 inches to 6 feet from ground
• In April Knotweed clusters can be enclosed in drum liners
• Cutting of dried stems in March speeds the injection process in established stands |
When a nor easter hit New Jersey on April 15, 2007 neighbors in the area of the Walnut Street Park stream watched as water levels steadily rose in their yards. Basements that had not flooded in 36 years were flooding; a pear tree planted 20 years ago toppled over on Fox Place, barely missing a house. Many other large trees in the vicinity were also in danger of toppling over from the saturated soil conditions.
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Japanese Knotweed eradication was begun in the flood plain of a stream in South Plainfield, NJ, July 2007. In this area there was a solid mono-culture of this invasive plant blocking the flow path nearly completely. Experts estimate that this area had Knotweed for at least 20 years. Our initial studies are described subsequently on this web site. This web site’s primary mission is to facilitate communication and to foster the evolution of pragmatic and efficient stem injection protocols in development over the 2007-2008 time period. These new protocols may have implications for treating Knotweed infestations in much larger areas than presently demonstrated.
It is widely appreciated and understood that stem injection of undiluted herbicide (AquaMaster, Rodeo) into the stems of Knotweed is a powerful and effective method to control and/or eradicate this invasive plant. However, to be successful it is necessary to inject every stem, regardless of size, in a given area. Each stem is connected to a separate rhizome and success in eradication requires that all rhizomes be treated. Thousands of acres have been treated in Oregon and Washington State using stem injection procedures. Major infestations of the Eastern Seaboard and Pennsylvania are noteworthy. JK Injection Tools has designed a gun-type injector for Knotweed that is commercially available. This company has also developed an improved, alloy-hardened, short needle design that speeds the stem injection process. Information on their web site is quite useful as an introduction to this technology, and to the environmental dangers of Knotweed: www.jkinjectiontools.com
Effective Treatment Strategy and Public Awareness
Dr. Ron Crockett an expert in Weed Management from Clark County, Washington State has advised our local officials that the most effective method of Knotweed control leading to eradication is to treat every new eruption site quickly by using stem-injection procedures. This early prevention is the only cost effective way to prevent the spread of Knotweed and forestall the eventual greater expense of treating established areas of infestation. Informing the public about Knotweed infestation and control will allow new eruption sites to be identified at an early stage. By treating all newly emerging sites expensive re-planting at these eruption sites is a non-issue. Knotweed’s greatest danger is its explosive rate of growth. For example, an infested area in Piscataway that had 20 dried stems in March expanded to about 800 new stems in June of 2008. Without dedicated intervention prolific stem generation will continue to invade greater and greater portions of creek and stream banks. This invasion results in high soil erosion rates, expanding generation and collection of debris leading to eventual blockage of impacted water courses.
The Present Approach
One of our discoveries is using a pre-drilled hole in the Knotweed stem where the JK injector gun is used as a tool to deliver the 5 cc of herbicide. This protocol is simply having the drill in one hand and the injector gun in the other hand. The number of stems that can be injected per hour is about the same using an injector gun alone or combining with the small Li-ion battery drill, i.e., about 450 stems per hour. But one of the advantages of the drill-first approach is that a 1/8 inch drill hole all but eliminates splitting of thin, fragile stems, and eliminates “blow back” of herbicide from internal pressure within the stem when the injector gun is used by itself. By using the drill-first approach almost 100% of the stems can be injected in an efficient and rapid fashion.
It was also demonstrated that it is equally effective to inject the herbicide into the drilled hole in the stem 2 to 6 feet from the ground. [A recent publication by Erin N. Hagan and Peter W. Dunwiddie, Weed Science Society of America, Vol. 1, Issue 1 (Jan – March 2008), pp. 31-35 independently reported that injection near the ground is not necessary]. Having the option of injecting the herbicide at different heights is also effective at speeding the herbicide delivery process as one works through dense Knotweed stands.
We also found that cutting of the dried Knotweed stems of dense stands in early March with a brush cutting tool, before new stem growth, speeds the process of stem injection. All of the new stems are more easily drilled and/or injected if the dried stems are already felled. Cutting the dried stems also facilitates freer movement through the Knotweed stands.
Knotweed stems in tree shade are softer and can be penetrated without drilling by use of the short JK injection needle. This applies even for thin Knotweed stems. There is no advantage to drill a hole into these soft stems. Shaded stands of Knotweed can be injected at a much greater speed than those in full sun. Sun-exposed stands are denser with tougher, thicker stems.
What is most revealing from our work from October 2007 to January 2008 is that the effectiveness of stem injection continues well into the winter months. Only during February and March do the stems dry out too much to promote effective glyphosate transport to the rhizome root-like mass under ground. As soon as new stems emerge in April stem injection can be resumed. As a consequence of these studies it is evident that stem injection can be done for 10 months of the year in New Jersey. Softening of the Knotweed’s tough stems by a hard frost facilitated injection compared to toughened stem during the summer months. Between 80-95% effective control of Knotweed was demonstrated by stem injection both before and after the hard frost of the 2007 treatment period.
Most importantly, it was demonstrated that by combining stem injection in the fall with injection in the same area the following April for emerging new Knotweed stems that 100% eradication of Knotweed was possible. In these 100% eradicated areas, the main pioneering plant that invaded the treated areas was almost exclusively jewel weed.
An alternative method of delivering the herbicide to the stem than stem penetration by use of a needle or a drill bit was also shown to be effective. This method involved perpendicular cutting of the stem just above the second node with a reciprocating saw. Herbicide was then injected down the stem by penetration of the thin, soft membrane of the second node. Analogous to other penetrated-stem injections, 80-95 % effective control of stem populations was obtained by this alternative method.
Non-herbicide Knotweed Control Protocol
Another method of Knotweed control was investigated in late March –early April 2008. In previously mowed areas of the flood plain, sixty large Knotweed clusters were enclosed within thin, plastic 55 gallon drum liners. (Liners had to be attached via cable ties to the stems to prevent the wind from removing them). These plastic enclosures effectively limited the maturation of the plant by severely restricting light transmission to the plant. Being inside the bag solar-induced heat also stressed the plants resulting in some stem rotting. The survival of the majority of the stems inside the plastic drum liners in July led to stem injection with 5 cc of herbicide of all the stems. For removal purposes it was effective to cut the stems at ground level. The entire bagged mass was put in a dumpster.
Equipment Development
It is possible that herbicide injection can be accomplished by the use of a battery-powered pump (BPP). Several prototypes are in process of being evaluated. The advantage of the BPP is that the herbicide is pumped from a large container eliminating constant re-filling, or exchange, of the hopper on the JK stem injection gun. Greater speed of stem injection seems possible with a BPP system than with the mechanical JK injector gun. However, this needs to be proven under field conditions before the system’s design can be finalized for large scale testing. Development work with these systems is continuing.
Acknowledgements
The administration of these studies by Alice Tempel, Environmental Coordinator of South Plainfield, was critical to this project’s growth and maturation. Alice was also instrumental in applying for a Grant to continue this work within the Borough. Mayor Charlie Butrico of South Plainfield, supported this work with purchase of herbicide and equipment, as well as mustering the important work of stream bed clean-up by the Department of Public Works. Contributions of Boy Scout troops of South Plainfield have aided the stream restoration, as well. Mike and Rachael Callanan and Herman Maurer have been active volunteers in the stream restoration work over this past year. Valuable input from Dr. Ron Crockett, Clark County Weed Management, Washington State was also important to moving this project forward. Betty Ann Kelly and Harry Allen from New Jersey’s Environmental Community have also been instrumental to this program’s direction.
The storm, with a recorded barometric pressure of 968 millibars, was equivalent to that of a moderate Category 2 hurricane and reminiscent of Hurricane Floyd that hit the area in September 1999. During the next 60 days water-logging continued, with sump pumps running non-stop in many of the affected homes. Residents Bob Smith and Larry Murrell, along with Mike and Rochelle Callanan and Herman Maurer, noticed the stream was not flowing where it crossed Walnut Street. After a group of neighbors cleaned the stream bed at the end of McDonough Street and O?eefe Lane, the water level continued to get higher, with very little water flowing freely. |
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When the depth of water in the stream reached about 30 inches, neighbors surmised there must be some type of dam beyond the Walnut Street bridge. Murrell, dressed in his 30 year-old fly fishing waders, walked the stream until reaching what was estimated to be a 40-foot blockage behind Fox Place. After a few hours of pulling branches away from the blockage, the water began to flow freely.
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Residents then met with engineers from the consulting firm CME and Mayor Charles Butrico. Assisted by the Department of Public Works, a dumpster from Pinto Brothers Disposal was placed behind Fox Place and clean up crews were organized. More than 25 volunteers worked several Saturdays each month to help with clean up efforts. Vounteers included the Callanans, Maurer, Murrell, Butrico and Councilmembers Joe Scrudato and Ray Petronko, then councilmembers Dennis Cerami and Kathy Thomas, Environmental Specialist Dr. Alice Tempel and Jeffrey Pauls along with members of his Boy Scout Troop 309. |
Of Knotweed, 2007-2008
In South Plainfield, NJ
The Treated Area Is Along the Creek
Passing Through Walnut Street Park
Larry Murrell
2/21/2008
Summary
Multiple methods of treatment were investigated that covered a wide choice of treatment procedures. The Borough of South Plainfield paid for the Rodeo herbicide, the syringes, and the JK Injector gun in support of this program. The primary goal of this report is to precisely locate the exact areas treated by each method so that the results can be compared in June and July. The main impetus for these studies originated from input from Chris Obropta’s group from Rutgers, and from Ron Crockett’s correspondences from Clark County, Washington State. The Rutgers’ protocol involved cutting of the Knotweed stems in July and then to spray the new growth in September. This is the method preferred by NJDEP Game and Fish. Stem injection of Knotweed was investigated using methods adapted primarily from the Oregon/Washington areas of the country. The actual Rodeo treatment period in South Plainfield covered about five months overall. This long interval was not planned in the beginning but was a consequence of the arrival of the Rodeo herbicide, the parrot-feeding syringes, and the JK Injector gun spread over a significant time period. This long interval of time may have turned out to be an advantage in that a new protocol of treatment may have been discovered inadvertently using stem injection of herbicide after the first frost of the season. The effectiveness of the stem injection method over a long period of time from late September through January is provocative and controversial. Yet, there may be unexpected pros and cons of doing the treatment after the first frost of the fall season but before the stems become weakened and broken as the late fall/winter season progresses.
Backpack Canister Spraying
One method recommended by Chris Obropta’s group from Rutgers is a method used by NJDEP Game and Fish. In this method the Knotweed is cut in mid summer, July and August and the re-growth which is a dense green blanket about 30 inches tall is sprayed with Rodeo in September. For this method to be successful the Rodeo must be combined with a surfactant that improves the adherence of the herbicide to the leaves. The Rodeo concentration was 8 wt. % as described in the Rodeo literature as that need for Knotweed control. (For this method to be successful re-planting and successive treatments over 2-3 years is required according to input from Obropta’s team). The entire canister spraying was done on one day, September 16, 2007.
One large area, called Plot 1A, is the entire flood plain from the boundary of the Cremona’s residence, at Fox Place, to the edge of the creek. This area is easily recognizable from the aerial map. Plot 1B is a large area about 10 feet wide running parallel to the creek but across the creek running the entire length of the aforementioned flood plain. (Both of these areas were planted with shrubs after the spraying was completed).
Cut Stem Drizzle Treatment
In Plot 2A and 2B the Knotweed stems were cut with a reciprocating saw over several weeks in September. These areas included areas on the Chestnut Street side of the creek and the New Brunswick side of the creek but down stream from the flood plain about 30 feet. For these two areas there was very little re-growth of new green shoots from the stems. However, Rutgers advised us that it was still prudent to saturate the Knotweed stems in this area with the same 8 wt. % Rodeo plus surfactant mixture as used Plots 1A and 1B. Both plots 2A and 2B were re-planted on the upper banks with hardy shrubs. It is expected that Plots 2A and 2B would require treatment for at least two years due to the rather uncontrolled method of herbicide adsorption into the rhizome structure of the Knotweed through the treated stems. These two plots were treated with the saturating drizzle of Rodeo on September 16, 2007.
Stem Injection Treatment
From November 4th to November 19th, 2007 parrot-feeding syringes were used to inject 1000 Knotweed stems with 5 cc of Rodeo. (This amount of herbicide is that recommended in the Dow Agrosciences literature, and is that amount found essential by D. Ron Crockett). This large treatment area will be referred to as Plot 3A and 3B. Plot 3A was before the first frost of the season and Plot 3B after a mild frost. This area is described as the line drawn along the Eastern-edge of the Cremone house in the aerial photograph to the creek bank to the area which is the Western-edge of the Cremone property line. This area is entirely on the New Brunswick Avenue side of the creek. The area was treated entirely by either puncturing the stems with a rotary saw or by cutting smaller stems parallel to the ground just above the second node. The tip of the syringe was either placed in the cut hole in the stem or the tip was used to puncture the membrane of the second node. The time to inject the herbicide into the stem was kept to about 15 seconds, or less, to ensure that there was minimum damage to the interior stem membrane. This short time is necessary according to some literature due to possible damage to the inner stem membrane by exposure to air.
Plot 3A is distinguished from Plot 3B by treatment before and after a mild frost, respectively. The final 300 stems of the total 1000 stems were treated after a mild frost turned the stems deep green in color, and where the leaves had partially dropped to the ground. This 300 stem-treated area, Plot 3B is at the very terminus of the Knotweed infestation on this bank of the creek, and covers two large clusters immediately along the stream bank and Knotweed stems further from the creek in a horse-shoe shaped area. This area is bounded by a small drainage creek that enters perpendicular to the Walnut Street Park creek. This small creek enters from the New Brunswick Avenue side of the creek. Two weeks after stem injection all of the stems in this area were cut and stacked above the normal-flow, high water line.
After a hard frost occurred 350 stems were injected on the Chestnut Street side of the creek in three intervals from November 19th to November 27th, 2007. This area is designed as Plot 4. The area treated was on the steep slope of the creek on the Western-most edge of the Cremone property. The soil temperature was measured to be 40F to be certain that the stem injection was still possible according to communications with Dr. Ron Crockett. For these injections 125 stems were all cut with reciprocating saw above the second node. The 5 cc of Rodeo was injected down the stem by piercing the membrane of the second node. For the remaining 225 stems in Plot 4, which is further up stream toward the flood plain back of the Cremone residence, the herbicide was injected into a hole drilled with a rotary saw in the stem just below the second node. After one week the 225 stems were all cut with a reciprocating saw and stacked above the high water line.
In the first two weeks of December, 2007 in 3 sessions 375 Knotweed stems were injected with Rodeo directly adjacent to the stream from Walnut Street Bridge to the edge of the flood plain on both the Chestnut Street side of the creek and the New Brunswick Avenue side of the creek by puncturing the stem after drilling the stem with a rotary saw. This is designated as Plot 5A and 5B, respectively. The soil temperature during these injections was 40F.
About December 19th, 2007, using the JK Injector gun that arrived just days before, 500 stems were injected in about one hour. The treatment areas were Knotweed clusters higher on the creek banks on both the Chestnut Street side of the creek and on the New Brunswick Avenue side of the creek. These areas are designated as Plots 6A and 6B, respectively. The decision to do the injection this late in the season was based on the soil temperature being 38-40F in the both treatment areas. An area about 10-15 feet wide was treated parallel to the creek on both banks. The treatment area started with the edge of the areas in Plots 1A and 1B. The objective was to make a seamless coverage of the entire area using the two different approaches. In both of these plots the Knotweed clusters were all very large in size and very dense, probably growing in this area continuously for 20 years as estimated by Alice Tempel.
In the first week of January 200 stems were injected in a lightly infested area on the Chestnut Street side of the creek which covered the remaining area not treated in Plot 6A. The soil temperature during this injection sequence was about 34F. This treatment area is designated as Plot 7 and is butted by Walnut Street and a large fallen tree located about 20 yards toward the flood plain behind the Cremone residence. (There is a large untreated area of Knotweed on this side of the creek from the fallen tree toward the driveway from the Cremone property to the flood plain. In addition, areas that are untreated are on the upper banks of the creek directly behind the Cremone property and along the side of the road leading to the flood plain.)
In the second week of January, in one session 125 stems were injected with the JK Injector gun in quite large Knotweed clusters running parallel to Walnut Street from the Walnut Street Bridge headed toward New Brunswick Avenue. The area covered was estimated to be just 4 feet wide (one single Knotweed cluster in width) running for about 30 feet in length. This treatment was done on large clusters that had a lot of broken stems but where the stems were not broken within 12 inches of the ground. The New Brunswick Avenue edge of the treatment area has a small tree as a reference point. This area is designated as Plot 8.
In the second week of January in two sessions 475 stems were injected on the New Brunswick Avenue side of the creek. The soil temperature ranged from 32.4-34F depending on the location of the measurement and the depth of penetration of the probe into the soil. All of the injected clusters were marked with green spray paint. The band of treatment was aimed to go from the edge of the plot treated by canister spraying in a wide band all the way to the end of the Knotweed infestation at the property line of the first house when heading toward New Brunswick Avenue. This treatment area was almost exclusively large clusters in the treatment area except for isolated stems at the edge closest to New-Brunswick-Avenue-edge of the plot. This entire area is designated as Plot 9. There is some irregularity to the treatment area due to the presence of a large amount of grape vines mixed in with the Knotweed clusters. An attempt was made to remove the grape vines from the Knotweed injected area and to stack them in one single area for later removal. The goal was to treat the entire area in this area but stem injection was suspended due to time constraints.
It is estimated that there are about 15 large Knotweed clusters not treated by stem injection along Walnut Street in a 20-30 foot wide band that runs for about 70 feet on the New Brunswick Avenue side of the creek. It is also estimated that an additional 30 clusters and isolated stems surround a wetland formed directly opposite to the Cremone property on the New Brunswick Avenue side of the creek. All of these untreated clusters will be clearly distinguished by their robust height in June and July. Alternatively, these clusters could have some of their dry stems spray painted to distinguish the untreated clusters from the treated clusters designated by the green spray paint. Some method of treatment to distinguish the treated from the untreated clusters is recommended.
A team from Rutgers University, headed by Chris Obropec, corroborated the findings of the neighbors. Additionally, overgrown vegetation not native to this area was deemed a contributing factor in the blockage along the stream bed. Japanese Knotweed, or green bamboo, has added to the degradation of the stream bed over the past 30 years, causing extensive erosion and clogging the natural flow channel with silt, dirt and debris. |
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Advice from experts led to trying a method where herbicide is injected directly into the stem of the plants. To penetrate the stems tough exterior a rotary saw was used.
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Under the supervision of Tempel, and with herbicide provided by the borough, a large area of Knotweed was treated and was augmented last December by the addition of an injection gun made especially for Knotweed eradication efforts. A large area was treated using the gun in December and January to test the effectiveness of herbicide treatment well after several hard frosts had occurred. By doing the stem injection in the fall/winter, plus the injection of new stems emerging this past spring, a 100% eradication of Knotweed was proven. In April, Maurer and Murrell enclosed 60 large Knotweed clusters into 55-gallon plastic drum liners which successfully suppressed the clusters bio-mass production by limiting the light the plant could adsorb, rotting the leaves and stems. In June, Brian Zielinski contributed valuable hours by cutting the stems of the Knotweed with a brush wacker. Efforts are continuing in areas of the flood plain not treated last year. The ultimate goal is complete eradication of existing Knotweed infestation along the entire stream corridor. Efforts are also going to be extended to the Knotweed infesting the area further downstream on the former Gallini Farm property in Piscataway on New Brunswick Avenue. Blockage of the water flow on the farm property by dams have all been removed by Joe Pfeiffer, who spent three hours removing them in March and more than 50 hours by Larry Murrell. All of these efforts would benefit from additional volunteer involvement, which is always welcomed. Groups interested in volunteering their time to the stream restoration project can E-mail LarryMurrell@comcast.net or contact Dr. Alice Tempel at (908) 226-7621. With thanks to Larry Murrell, who not only contributed hundreds of volunteer hours to this project, but also supplied the Observer with pertinent details and additional photos. |
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Special Thanks to the South Plainfield Observer for this text and Photos Reprinted with permission; all rights reserved. Copyright 2008 The South Plainfield Observer |
In all future efforts it is proposed that areas to be treated be designed by prior agreement and by color-coding treatment in some way, either with a coded label or colored spray paint. The use of blazon colorant added to the Rodeo has been suggested as a method to mark the treated clusters, and even individual stems that have been treated by stem injection. If an organized effort is set in place to eradicate Knotweed by stem injection it is also important that areas with the smallest extent of infestation have priority compared to more heavily established area. This strategy will eliminate the undesirable expense of re-planting treated areas. (With that said, it appears that areas treated by stem injection are making a surprising recovery of natural vegetation adjacent to Fox Place).
Another proposal for future consideration would be to encapsulate all of the remaining clusters of Knotweed in properties owned by the Borough with tightly attached plastic bags to use solar energy to limit the Knotweed recovery and to simultaneously facilitate the restoration of native plants in infested areas. Further, in the area untreated by either canister spraying or by stem injection in the vicinity of Fox Place it would be possible to encapsulate the remaining Knotweed clusters in plastic bags. Property owner permission is essential to secure the right to use this passive method for Knotweed growth suppression adjacent to Fox Place on either side of the creek.