Progress 10/02/03 to 10/01/07
Outputs
OUTPUTS: Starting in 2003, research was conducted on control methods for Oriental bittersweet (Celastrus orbiculatus) and pale swallowwort (Cynanchum rossicum) at Bluff Point Coastal Reserve in Groton, CT and shrub honeysuckles (Lonicera species) at Pattagansett Marsh in Niantic, CT. These non-native, invasive plants threaten the health of ecosystems at these Long Island coastal sites and many other locations in the northeastern U.S. Oriental bittersweet is a woody vine that wraps around and climbs trees and grows over lower vegetation. Bittersweet vines are widespread in parts of the forested section at Bluff Point and are adversely affecting trees and shrubs. Pale swallowwort is an herbaceous perennial in the milkweed family. It is spreading rapidly in the natural area preserve at Bluff Point and is outcompeting two rare native plants in the cobble beach habitat. Shrub honeysuckles are dominating a wooded section of Pattagansett Marsh, adjacent to Old Black Point Beach. An
evaluation of control methods for these invasive plants was much needed. As a result of this project, highly effective control methods were developed that use minimal amounts of herbicide in an environmentally sound manner. Information gained during this project has been disseminated to communities of interest in a number of ways. Oral and poster presentations were presented at Connecticut Invasive Plant Working Group symposia in 2004 and 2006. More than 350 people from a wide range of professions and interest groups attended each of these symposia. Posters were also presented at the New England Invasive Plant Summit (2005), Connecticut Conference on Natural Resources (2007) and the Rhode Island Natural History Survey's conference on invasive species (2007). In addition, research posters were presented at annual meetings of the Northeastern Weed Science Society and the Weed Science Society of America in 2006. More than 200 people attended each of the aforementioned conferences. Talks
about the project and walking tours of the study sites have been given to smaller groups from The Nature Conservancy, Connecticut Department of Environmental Protection (DEP), and land trust organizations. A full report on the project was submitted to Connecticut DEP in January 2007. Project methodology and results have been incorporated into numerous presentations given to groups interested in invasive plant management, and information has been disseminated to hundreds of people who have inquired about control options via telephone and email over the past 4 years.
PARTICIPANTS: There were two main participants in this study: Todd L. Mervosh, the principal investigator and Assistant Scientist II at The Connecticut Agricultural Experiment Station (Windsor, CT) and David Gumbart, Assistant Director of Land Management for The Nature Conservancy, Connecticut Field Office (Middletown, CT). Dr. Mervosh designed the procedural details of the project, was actively involved in experimental set-up (selection and tagging of bittersweet vines and honeysuckle shrubs, layout of swallow-wort plots), applied all of the herbicide treatments, participated in all data collection, analyzed data, and prepared written reports, posters and oral presentations. Mr. Gumbart was instrumental in obtaining permission to conduct research at the study sites and in securing funding from the Connecticut DEP Office of Long Island Sound Programs, via The Nature Conservancy. He also was actively involved in the experimental set-up for all three invasive plants, treatment
applications (primarily cutting and hand pulling), data collection, and presenting project results. In addition, Mr. Jeremy Leifert, a seasonal research assistant in 2003 and 2004 for The Connecticut Agricultural Experiment Station, provided considerable technical assistance during the first two years of the project.
TARGET AUDIENCES: Connecticut Department of Environmental Protection (managers of state parks, forests, reserves and natural area preserves), The Nature Conservancy and other conservation groups, land trusts, private property owners, invasive plant specialists, weed scientists, garden club organizations and other parties concerned with managing invasive plants.
PROJECT MODIFICATIONS: After the proposal title was submitted in 2003, it was determined upon closer examination that the swallow-wort species at the study site was pale swallow-wort (Cynanchum rossicum or Vincetoxicum rossicum), not black swallow-wort (Cynanchum louiseae or Vincetoxicum nigrum). Instead of Asiatic bittersweet as the common name for Celastrus orbiculatus (as in the proposal title), the more widely accepted common name of Oriental bittersweet was used. Other than a preliminary experiment, the proposed study on management of Japanese knotweed was not conducted because a sufficiently large infestation was not accessible. However, a study on the control of shrub honeysuckles near the coast of Long Island Sound was added to the project.
Impacts
For Oriental bittersweet and shrub honeysuckles, treatments that involved cutting the woody stems and applying a small amount of herbicide directly on the cut-stump surfaces were very effective at preventing re-growth of these invasive plants. In terms of herbicide active ingredients, glyphosate was as effective or superior to triclopyr as a cut-stump treatment. For bittersweet vines, application timing (spring, summer or fall) was not a significant factor in preventing new sprouts the following year. Less than 1 milliliter of herbicide was applied to each cut stump. Compared to spraying herbicide over foliage, this combination of cutting followed by directed application of herbicide greatly reduces the amount of chemical applied and eliminates the risk of off-target spray drift. Thus, the cut-stump treatment method was found to be highly effective and environmentally sound for bittersweet and honeysuckle control. For pale swallow-wort, pulling or cutting stems reduced
re-growth only slightly. Dabbing a small amount of glyphosate or triclopyr on freshly cut stems greatly reduced re-growth, pod formation and seed production. This cut-stem herbicide treatment is useful for small patches of swallow-wort, but because of the labor involved in treating individual stems, it is less practical for large infestations. In such cases, a foliar spray containing glyphosate (diluted according to label instructions) as pods were starting to form was the best treatment at preventing re-growth of swallow-wort. These results changed some assumptions previously held by the principal investigator and many others. In particular, the lack of an application timing effect for bittersweet control and that glyphosate was generally more effective than triclopyr in controlling these three species were unexpected results. Dissemination of these findings has led to changes in management practices for bittersweet, swallow-wort and honeysuckle species by Connecticut DEP, the
Connecticut Chapter of The Nature Conservancy, and other land management groups in New England.
Publications
- Mervosh, T. L. and D. Gumbart. 2007. Management of Oriental bittersweet (Celastrus orbiculatus) and pale swallow-wort (Cynanchum rossicum) at Bluff Point Coastal Reserve. Connecticut Conference on Natural Resources, p. 24 (abstract).
- Mervosh, T. L. and D. Gumbart. 2007. Management of Oriental bittersweet, pale swallow-wort and shrub honeysuckle at Connecticut coastal sites. Rhode Island Natural History Survey 12th Annual Conference, p. 5 (abstract).
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Progress 01/01/06 to 12/31/06
Outputs
Collection of field data for experiments on control of Asiatic (Oriental) bittersweet, pale swallowwort and Japanese knotweed was completed in the summer of 2005. An additional experiment to evaluate control methods for non-native honeysuckle (Lonicera) shrubs was initiated in August 2005. A variety of invasive honeysuckle species are prevalent throughout Connecticut, especially near coastal areas. The honeysuckle control experiment was conducted in a wooded area at Pattagansett Marsh, a preserve of The Nature Conservancy, near Old Black Point Beach in Niantic (town of East Lyme, CT). The study site was within 100 feet of the Long Island Sound shoreline. The objective of the experiment was to evaluate cut-stump herbicide treatments because spraying the foliage of honeysuckle shrubs would not be an environmentally sound method at such a location. Selected honeysuckle shrubs were tagged at the base in early August 2005. Shrubs were cut down with a saw just above the
crown level on August 17, 2005. The number of cut stems per stump and diameters of each cut stem were recorded. Within 1 hr of cutting, herbicide treatments were applied to the cut-stem surfaces of the stumps. Each treatment was applied uniformly with a paint brush to three stumps. Treatments consisted of an "untreated check" (stems cut / no herbicide), "glyphosate" [isopropylamine salt of glyphosate (4.1% or 20.5% active ingredient)], "triclopyr amine" [triethylamine salt of triclopyr (4.4% or 22.2% active ingredient)], or "triclopyr ester" [triclopyr butoxyethyl ester (6.2% or 30.8% active ingredient)]. Stumps were evaluated on May 18, 2006 for the number of new sprouts and sprout lengths. Prolific sprouting occurred from untreated honeysuckle stumps cut in August 2005. By May 2006, an average of 47.5 sprouts had emerged from these stumps, and the combined length of the new sprouts was estimated at 19.8 meters per stump. Both glyphosate treatments applied to freshly cut stumps were
highly effective, completely preventing sprouting the following spring. The triclopyr treatments greatly reduced sprouting, but were not as effective as the glyphosate treatments. The efficacy of the triclopyr treatments improved with higher concentration of active ingredient. At lower triclopyr concentrations, the number of new sprouts was reduced 69 to 75%; at higher triclopyr concentrations, the number of new sprouts was reduced 90 to 98%. The triclopyr amine formulation was as effective as or slightly more effective than the triclopyr ester formulation. This method of cutting and applying herbicide directly onto cut surfaces (cut-stump treatments) is an effective and environmentally sound strategy for controlling invasive woody plants.
Impacts
I expect this project to provide foresters, ecologists and other land managers with useful information for controlling the following non-native, invasive plant problems: Asiatic bittersweet, pale swallowwort, Japanese knotweed and honeysuckle shrubs. The project will help identify control options that are highly effective, practical to apply, and environmentally sound.
Publications
- Mervosh, T.L. and Gumbart, D. 2006. Management of Oriental bittersweet (Celastrus orbiculatus) and pale swallowwort (Cynanchum rossicum) at a Connecticut coastal reserve. Weed Sci. Soc. Amer. Abstracts 46:20.
- Mervosh, T.L. and Gumbart, D. 2006. Management of Oriental bittersweet vines and pale swallowwort at a Connecticut coastal reserve. Proceedings, Northeast. Weed Sci. Soc. 60:6.
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Progress 01/01/05 to 12/31/05
Outputs
Research on control of Asiatic (Oriental) bittersweet (Celastrus orbiculatus) and pale swallowwort (Cynanchum rossicum) began in 2003 and continued through 2005 at Bluff Point Coastal Reserve in Groton, CT. These non-native, invasive plants threaten ecosystems at this natural area along Long Island Sound and many other locations. Oriental bittersweet, a woody vine, is widespread in forested sections at Bluff Point and is adversely affecting trees and shrubs. Pale swallowwort, an herbaceous, rhizomatous perennial, is outcompeting two rare native plants along the shoreline, particularly in the cobble beach habitat just above the high tide line. For Asiatic bittersweet, we tagged vines in two size classes: diameters of 15 to 25 mm (small) and diameters of 25 to 40 mm (large). Vines were measured and treatments were applied to vines between 15 and 30 cm above ground. Each treatment was applied randomly to ten vines (five small and five large) at each of three timings
(May, August, November) in 2003, and similarly to a different set of vines at the same timings in 2004. Herbicides were applied undiluted with a paint brush. Basal-bark (BB) treatments consisted of 1.5 ml of herbicide applied uniformly to the lower bark of uncut vines. Cut-stump (CS) treatments consisted of 0.75 ml of herbicide applied to the stump surface of freshly cut vines. Eight treatments were applied: BB untreated (uncut check), BB triclopyr ester (61.6% ai), BB triclopyr ester (13.6% ai), CS untreated (cut check), CS triclopyr amine (44.4% ai), CS triclopyr amine (8% ai), CS glyphosate (41% ai), CS glyphosate (25% ai). Vines were evaluated 1 year after treatment application by scraping off a section of bark just above ground level to examine the vascular cambium tissues. CS herbicide treatments were generally more effective than BB treatments, especially for treatments applied in November 2004. All CS treatments with either triclopyr or glyphosate were effective in reducing
vine survival (77 to 93% mortality) and number of sprouts from stumps or roots (91 to 99% reduction). For pale swallowwort, 1.83 x 3.05 m plots were established in areas of high infestation along the cobble beach. Treatments (RCB design with three replicates) applied to plots in July 2003 and again in August 2004 included hand pulling, cutting, application of glyphosate (20.5% ai) or triclopyr amine (22.2% ai) to cut stems, and foliar sprays of glyphosate (0.82% ai) or triclopyr amine (0.89% ai) applied in a spray volume of 25 gallons of water per acre. Plots were evaluated for percent area covered by swallowwort, swallowwort vigor, and presence of other vegetation. By July 2005, glyphosate foliar sprays and cut-stem treatments with glyphosate or triclopyr caused the greatest reduction in the amount of swallowwort (64 to 76% reduction in number of stems), and the glyphosate spray treatment was most effective in reducing swallowwort vigor (77% reduction in vigor, based on visual
evaluations). Triclopyr foliar sprays caused temporary injury but swallowwort recovered, and long-term control was no better than that provided by hand pulling or cutting once per year.
Impacts
I expect this project to provide foresters, ecologists and other land managers with useful information for controlling the following non-native, invasive plant problems: Asiatic bittersweet, pale swallowwort and Japanese knotweed. The project will help identify control options that are highly effective, practical to apply, and environmentally sound.
Publications
- Mervosh, T.L. and Gumbart, D. 2005. Control of Oriental bittersweet, pale swallowwort and phragmites at Bluff Point Coastal Reserve in Connecticut. Abstract, New England Invasive Plant Summit, Framingham, MA, Sept. 16-17, 2005. p. 33-34.
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Progress 01/01/04 to 12/31/04
Outputs
Research was initiated in 2003 at Bluff Point State Park and Natural Area Preserve in Groton, CT for control of Asiatic bittersweet (Celastrus orbiculatus) vines in a woodland and pale swallowwort (Cynanchum rossicum) growing along the shoreline. [Note: upon closer examination, plants were identified as pale swallowwort instead of black swallowwort, thus explaining the apparent inconsistency with the project title.] These non-native, invasive plants threaten the health of ecosystems at this coastal location and in many other areas throughout the Northeast. First-year treatments were applied in 2003. In 2004, these treatments were evaluated, and the same treatments were applied again (to a different set of bittersweet vines, but to the same swallowwort plots). For Asiatic bittersweet, vines were selected in two size classes: diameters of 15 to 24 mm (< 1 inch) and diameters of 25 to 40 mm (> 1 inch). Treatments were applied according to procedures in the project
proposal, except in 2004 the application timings were in May, August and November. Treatments consisted of different formulations of the herbicides glyphosate or triclopyr applied either to basal bark or to the stump surface of freshly cut vines. Vines were evaluated 1 year after treatment by scraping off a section of bark just above ground level to determine if the vascular cambium tissues were dead or alive. Also, the number and length of any new sprouts from above or below ground were noted. Treatment efficacy was not affected significantly by application timing. Combined over all timings in 2003, the following number of bittersweet vines (of 30 treated) were still alive in 2004: uncut check (28), Garlon 4 [triclopyr ester, 62%] basal-bark (6), Vine-X [triclopyr ester, 14%] basal-bark (11), cut check (25), Garlon 3A [triclopyr amine, 44%] cut-stump (3), Brush-B-Gon [triclopyr amine, 8%] cut-stump (8), Roundup Pro [glyphosate, 41%] cut-stump (1), Roundup Homeowner Concentrate
[glyphosate, 25%] cut-stump (2). Vines cut without herbicide produced an average of 2.4 new sprouts per vine. All herbicide treatments either eliminated or greatly reduced sprout formation. Bittersweet vines treated in 2004 will be evaluated in 2005. For pale swallowwort, an area of the cobble beach infested with this plant is the experimental site. According to procedures in the project proposal, treatments were applied in July 2003 and again to the same plots in August 2004. In July 2004, plots in which plants were pulled or cut the previous year had slight reductions in swallowwort density. Although the triclopyr spray treatment reduced pod formation, swallowwort vigor was not affected in 2004. The largest reductions in swallowwort density and vigor occurred in plots sprayed with glyphosate and those in which glyphosate or triclopyr were applied directly to cut stems. Swallowwort plots will be evaluated again in 2005. A preliminary experiment on management of Japanese knotweed
(Fallopia japonica) was initiated in 2004 and will be evaluated in 2005. A larger population of Japanese knotweed will be used in 2005 so that the full experiment can be conducted according to the proposal.
Impacts
I expect this project to provide foresters, ecologists and other land managers with useful information for controlling the following non-native, invasive plant problems: Asiatic bittersweet, pale swallowwort and Japanese knotweed. The project will help identify control options that are highly effective, practical to apply, and environmentally sound.
Publications
- No publications reported this period
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