Performing Department
Valley Laboratory
Non Technical Summary
In the United States, the non-native invasive plants cause economic losses worth $28 billion per annum and each year, more than 700,000 ha of the wildlife habitat are being invaded. Mugwort (Artemisia vulgaris L.) is a non-native invasive plants which has colonized a wide variety of habitats such as roadsides, floodplains and riparian areas, pasture and rangeland, rights-of-way, and various agronomic, turf and landscape settings. It is considered as one of the 10 most troublesome weeds in the US nursery industry. Mugwort is a serious threat to the diversity of native flora and also is a serious human and domestic animal health hazard; mugwort pollen is well known allergen responsible for hay fever and asthma. Mugwort's rapid spread is attributed to its extensive underground rhizome system and resistance to chemical and cultural control tactics. Current mugwort management relies mainly on herbicides and few nonchemical options are available for mugwort control. Many of these herbicides are associated with adverse environmental impacts, or the effective rates are cost prohibitive, or the label does not permit use in certain situations. Recently, the State of Connecticut has passed legislation prohibiting the use of pesticides, including herbicides, on the grounds of day care centers, and elementary and middle schools. It is expected that public demand for alternative nonchemical weed control options will continue to grow in the future. This research will pursue an economical, environment friendly, and sustainable approach to manage mugwort in various crop (pastures and rangelands) and non-crop situations (roadsides, right of ways, and playgrounds of day care centers, schools etc.). It is expected that reliance on chemicals will be reduced and environment quality will be improved.The overarching goal of this project is to attempt an integrated approach to mugwort management by combining chemical options and nonchemical tactics, such as mowing and nitrogen fertilization, and overseeding desirable cool season perennial grasses. Research hypothesizes that repeat applications of low herbicide rates or mowing treatments will significantly eliminate above and belowground biomass of mugwort. Nitrogen fertilization will improve mugwort control with lower herbicide rates, enhance the competitive ability of native vegetation and facilitate a rapid restoration of native vegetation.Overseeding perennial grasses will alter mugwort's access to resources and reduce the likelihood of its reinvasion. Restoration or reestablishment of desirable vegetation will create a dynamic plant community that will strongly compete with mugwort for resources and resist reinvasion.PROPOSED METHODSTwo field experiments will be initiated in summer/fall 2016 at two locations in Connecticut. First experiment will involve an integrated approach to manage mugwort; three rates of nitrogen (0, 62, and 124 kg N ha-1), three herbicides (aminopyralid, clopyralid, and glyphosate), and three different rates of each herbicide will be evaluated. A second experiment will involve an integrated, completely non-chemical approach; three mowing frequencies (no mowing, mowing twice a month, mowing once a month, and mowing every two months), three rates of nitrogen (0, 62, and 124 kg N ha-1), two overseeding treatments (overseeding, and no-overseeding) will be evaluated. To evaluate the impact of different treatments, periodic data will be collected on soil nitrogen levels, mugwort rhizome and shoot biomass, height, percent control, percent cover, and native species diversity and percent cover inside multiple randomly placed 0.25 m2 quadrats per plot. Treatments will be continued for three consecutive years and measurements will be recorded each year.Results obtained from these projects will be presented at regional and national level workshops and meetings of weed science societies, the invasive plant council, and the Connecticut invasive plant working group. Information will also be made available to land managers, other scientists and the public at The Connecticut Agricultural Experiment Station's Annual Plant Science Day and other professional meetings. Publications in peer reviewed journals, and outreach and extension articles are planned for wider dissemination of the results.
Animal Health Component
90%
Research Effort Categories
Basic
10%
Applied
90%
Developmental
(N/A)
Goals / Objectives
The overarching goal of this project is to attempt an integrated approach to mugwort management by combining chemical options and nonchemical tactics, such as mowing and nitrogen fertilization, and overseeding desirable cool season perennial grasses. The following is hypothesized; that lower herbicide rates or frequent mowing will control or suppress mugwort; that fall application of nitrogen will benefit cool season vegetation and may also improve the effectiveness of herbicides or mowing on mugwort control; and that overseeding perennial grasses will alter mugwort's access to resources and reduce the likelihood of its reinvasion.The overall objectives of this research include:Objective 1: To evaluate the effect of nitrogen fertilization and herbicide rates on mugwort management.Objective 2: To evaluate the effect of mowing frequency, nitrogen, and overseeding perennial grasses on mugwort management.
Project Methods
Two field experiments will be initiated in summer/fall 2016 in Connecticut at two locations with natural mugwort infestations. First experiments will evaluate the effect of integrating nitrogen fertilization and herbicide rates on mugwort control. A second experiment will involve a total nonchemical approach utilizing mowing frequencies, nitrogen fertilization, and overseeding perennial grasses.Experiment 1: Evaluating the effect of nitrogen fertilization and herbicide rates on mugwort management.Experiments will be established in a split-split plot design with three replications. The main plot (30 x 9 m) will consist of three rates of nitrogen at 0, 62, and 124 kg N ha-1, and the subplot (9 x 9 m) will be three herbicides (aminopyralid, clopyralid, and glyphosate), and the sub-subplot (3 x 9 m) will consist of three application rates ( 0.07, 0.14, and 0.28 kg ha-1 for aminopyralid and clopyralid; and 0.55, 1.1, and 2.2 kg ha-1 for glyphosate). A nontreated control plot will be established for comparison. Nitrogen will be applied as urea (46% N) in the fall (late August/early September). Herbicide treatments will be applied with a CO2-pressurized backpack sprayer calibrated to deliver 280 L ha-1 at 276 kPa equipped with a four-nozzle boom fitted with AIXR 11003 flat-fan nozzles (TeeJet, Spraying Systems Co., P. O. Box 7900, Wheaton, IL 60189). Soil samples will be collected up to 10 cm depth in each main plot to determine differences in total nitrogen levels as a result of different nitrogen treatments. Baseline data will be collected on mugwort rhizome and shoot biomass, percent cover, native species diversity and percent cover inside multiple randomly placed 0.25 m2 quadrats per main plot before nitrogen fertilization. Observations will be recorded on mugwort height, and percent ground cover using two randomly placed 0.25 m2 quadrats per sub-subplot at 0, 30, 60, 240, and 360 days after herbicide treatments (DAT), but before the next year's nitrogen fertilization treatments are applied. Data on above- and below-ground mugwort biomass will also be recorded using two randomly placed 0.25 m2 quadrats per sub-subplot at 60, 240, and 360 DAT. Visual percent mugwort control will be assessed in each sub-subplot at 0, 30, 60, 240, and 360 DAT, on a 0 to 100% scale where 0 equals no control and 100 equals complete kill of aboveground growth. Data will also be recorded in each sub-subplot on native vegetation diversity, percent cover by species, collective aboveground biomass and injury following herbicide treatments within the same quadrat while recording mugwort growth parameters. Nitrogen and herbicide treatments will be continued for three consecutive years and measurements will be recorded each year.Data on response variables will be subjected to ANOVA using the PROC Glimmix procedure in SAS version 9.3 (SAS Institute Inc, Cary, NC). Nitrogen rates,herbicides, and application rateswill be considered as fixed effects; while experimental year, replication and its interactions with fixed effects will be considered as random effects in the model.Experiment 2: Evaluating the effect of mowing frequency, nitrogen, and overseeding perennial grasses on mugwort management. Experiments will be established in a split-split plot design with three replications. The main plot (30 x 9 m) will consists of three rates of nitrogen at 0, 62, and 124 kg N ha-1, subplots (9 x 9 m) will be four mowing frequencies (mowing twice a month, mowing once a month, and mowing once every two months), and sub-subplot (3 x 9 m) will be two overseeding treatments (overseeding andno-overseeding). A non-mowed control plot will be established for comparison. Nitrogen will be applied as urea (46% N) in fall (late August/early September). Overseeding treatments will include a mixture of cool season perennial grasses, including Kentucky bluegrass, hard fescue, and timothy in fall 2016. Kentucky bluegrass and hard fescue are dual purpose grasses used both as a forage and as a turfgrass. Kentucky bluegrass is able to withstand heavy grazing or mowing pressure compared to other species of grasses. Research on overseeding of Kentucky bluegrass and perennial rye mixtures indicated high turf quality when Kentucky bluegrass composed the majority of the stand (Niehaus, 1976). Soil samples will be collected up to 10 cm depth from each main plot to determine differences in total nitrogen levels as a result of different nitrogen treatments. Baseline data will be collected on mugwort rhizome and shoot biomass, percent cover, native species diversity and percent cover using multiple randomly placed 0.25 m2 quadrats within each main plot before first mowing operation. Each year, periodic observations will be recorded on mugwort height, and percent cover using two randomly placed 0.25 m2 quadrats per sub-subplot at 0, 30, 60, 180, and 360 days after first mowing treatment (DAT), but before the next year's nitrogen fertilization treatments are applied. Data on above- and below-ground mugwort biomass will be recorded using two randomly placed 0.25 m2 quadrats per sub-subplot at 60, 180, and 360 DAT. Visual percent mugwort control will be assessed in each sub-subplot at 0, 30, 60, 180, and 360 DAT, on a 0 to 100% scale where 0 equals no control and 100 equals complete kill of aboveground growth. Data will also be recorded in each sub-subplot on native vegetation diversity, percent cover by plant species for native and overseeded vegetation, and collective aboveground biomass at 90 and 360 DAT. Nitrogen and mowing treatments will be repeated for three consecutive years and observations will be recorded each year on mugwort, native vegetation and overseeded perennial grasses. Data on various response variables will be subjected to ANOVA using the PROC Glimmix procedure in SAS version 9.3 (SAS Institute Inc, Cary, NC). Nitrogen rates, mowing treatments and overseeding will be considered as fixed effects; while experimental year, replication and its interactions with fixed effects will be considered as random effects in the model.