Source: CONNECTICUT AGRICULTURAL EXPERIMENT STATION submitted to
INTEGRATED MANAGEMENT OF MUGWORT (ARTEMISIA VULGARIS L.): COMBINING CHEMICAL AND NONCHEMICAL CONTROL TACTICS, NITROGEN FERTILIZATION, AND OVERSEEDING
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
NEW
Funding Source
Reporting Frequency
Annual
Accession No.
1009011
Grant No.
(N/A)
Project No.
CONH00817
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Jan 13, 2016
Project End Date
Jan 10, 2019
Grant Year
(N/A)
Project Director
Aulakh, JA, S.
Recipient Organization
CONNECTICUT AGRICULTURAL EXPERIMENT STATION
PO BOX 1106
NEW HAVEN,CT 06504
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
0%
Research Effort Categories
Basic
10%
Applied
90%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2162300114090%
2131699107010%
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.

Progress 10/01/16 to 09/30/17

Outputs
Target Audience:Results from successful treatmentswere shared with the pasture and hayfield growers and land conservation trusts who wanted (called in) to know effective herbicide treatment for its control. Changes/Problems:Objective 2: "Evaluating the effect of mowing frequency, nitrogen, and overseeding perennial grasses on mugwort management" will be dropped: Two year nitrogen and mowing treatments did not show any improvement in mugwort control. Therefore, It is highly unlikely that future continuance of this approach will be successful for mugwort control. What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals?Objective 1: Evaluating the effect of nitrogen fertilization and herbicide rates on mugwort management: Nitrogen fertilization will be continued in all plots. Herbicide treatments (Clopyralid and aminopyralid)will continue for one more year. Data will be collected on various soil and plant variables under study. Results from the first year research data will be demonstrated (Field plot demonstration/poster presentation) at the CAES Plant Science day in August 2018. Objective 2: Evaluating the effect of mowing frequency, nitrogen, and overseeding perennial grasses on mugwort management: Since there was no improvement in mugwort control following aggressive mowing treatments for two consecutive years, this study (Objective 2) will be discontnued.

Impacts
What was accomplished under these goals? Objective 1: Evaluating the effect of nitrogen fertilization and herbicide rates on mugwort management. Two-years dataonmugwort rhizome and shoot biomass, percent cover, stem density, and plant height indicatethat various nitrogen fertilization and herbicide treatments have resulted in 75 to 98% mugwort control especially with different rates of glyphosate and aminopyralid. Lower ratesof glyphosate (0.55 kg ae/ha)and aminopyralid (0.061 kg ae/ha) also controlled mugwort75 to 85%. Nitrogen fertilization treatments seem to have improved the growth of cool-season grassesand their competitivenesswith mugwort but did not affect herbicides effectiveness against mugwort. So far, all rates of clopyralid have failed to satisfactorily control mugwort; mugwort control was less than 30% even with the highest (0.56 kg ae/ha) clopyralid rate tested. Mugwort plots treated with different rates of glyphosate have been overseeded with a mixture of cool-season grasses to reestablish pasture grasses and prevent reinvasion of mugwort. Aminopyralid treated plots have a good to excellent come back of cool-season grasses, so no overseeding was required. Objective 2: Evaluating the effect of mowing frequency, nitrogen,and overseeding on mugwort management. Two-years dataonmugwort rhizome and shoot biomass, percent cover, and stem density indicatethat mugwort is highly resistant to different mowing frequencies. No interaction between nitrogen rateand mowing frequency has been reported for reduction in rhizome growth parameters. Following an agrressive mowing schedule for two years, mugwort rhizome biomass was reduced only by18% (374 g/ sqm) compared to the unmowed control (461 g/sqm) witha 15 day mowing Interval (10mowings from June to October). Even the 7 day mowing interval (20mowings from June to October) over the last two years could not reduce mugwort rhizome biomass more than 20%.Therefore,mowing is not likely to providesatisfactory control of mugwort.

Publications


    Progress 01/13/16 to 09/30/16

    Outputs
    Target Audience: Nothing Reported Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals?Objective 1: Evaluating the effect of nitrogen fertilization and herbicide rates on mugwort management:Nitrogen fertilization and herbicide treatments will continue, data will be collected on various soil and plant variables under study. Results from the first year research data will be demonstrated (poster presentation) at the CAES Plant Science day in August 2017. Objective 2: Evaluating the effect of mowing frequency, nitrogen, and overseeding perennial grasses on mugwort management: Nitrogen fertilization and mowing treatments will continue, data will be collected on various soil and plant variables under study. Perennial grass overseeding will be conducted in the fall (Sept-Oct) 2017. Results from the first year research data will be demonstrated (poster presentation) at the CAES Plant Science day in August 2017.

    Impacts
    What was accomplished under these goals? Objective 1: Evaluating the effect of nitrogen fertilization and herbicide rates on mugwort management:A field experiment has been initiated at the Lockwood Research Farm of the Connecticut Agricultural Experiment Station in Hamden, CT. Baseline data have been collected- soil samples have been taken to determine nitrogen levels following different N fertilization treatments. Data have been collected on Initial mugwort rhizome and shoot biomass samples, percent cover, and native species diversity before herbicide treatments application. Nitrogen fertilization and herbicide treatments have been applied. Visual assessments on % mugwort control, height, percent cover following 30 and 60 days herbicide treatments have been conducted. Objective 2: Evaluating the effect of mowing frequency, nitrogen, and overseeding perennial grasses on mugwort management:A field experiment has been initiated at the Lockwood Research Farm of the Connecticut Agricultural Experiment Station in Hamden, CT. Baseline data have been collected- soil samples have been taken to determine nitrogen levels following different N fertilization treatments. Data have been collected on Initial mugwort rhizome and shoot biomass samples, percent cover, and native species diversity before herbicide treatments application. Nitrogen fertilization and mowing treatments have been applied. Data have been collected on mugwort control, height, and percent cover; and native species cover and diversity at 30 and 60 days following last mowing treatment. Overseeding treatments have been deferred until fall 2017 due to lack of satisfactory mugwort control following first year mowing treatments.

    Publications