Developing and Improving Weed Control Strategies for Ornamental Nurseries, Greenhouses and Christmas Tree Productions

DEVELOPING AND IMPROVING WEED CONTROL STRATEGIES FOR ORNAMENTAL NURSERIES, GREENHOUSES AND CHRISTMAS TREE PRODUCTIONS

Sponsoring Institution

National Institute of Food and Agriculture

Project Status

ACTIVE

Funding Source

HATCH

Reporting Frequency

Annual

Accession No.

1023081

Grant No.

(N/A)

Cumulative Award Amt.

(N/A)

Proposal No.

(N/A)

Multistate No.

(N/A)

Project Start Date

Aug 1, 2020

Project End Date

Jul 31, 2025

Grant Year

(N/A)

Program Code

[(N/A)]- (N/A)

Recipient Organization
MICHIGAN STATE UNIV
(N/A)
EAST LANSING,MI 48824

Performing Department
Horticulture

Non Technical Summary
Controlling weeds in nursery and greenhouse production is economically important as they compete with the ornamental plants for soil, nutrients, water, light, space, and air within the container, as well as in the field. Weed competition results in a decrease in the quality, aesthetics, market value of the ornamental plants, or even death with severe competition with heavy infestation of weed species. In Michigan, the total financial impact of nursery and landscape production, including backward linked industries, is $1.26 billion. The ornamentalindustries of Michigan directly employ 13,269 employees. So, a little improvement in weed control can help nursery and greenhouse operators to improve their overall profitability and thereby directly impact Michigan's billion-dollar green industry. The main limitation ofweed control for greenhouse production is lack of herbicides labeled for greenhouse use. In nursery container production, herbicides used at higher rates for weed control can cause phytotoxicity to sensitive ornamental plants and can have residual effects as well. Hand weeding is very laborious, time-consuming, and expensive. Hence this research project was planned which will be focusing on both non-chemical and chemical methods of weed control. Non-chemical practices including different types of organic mulch materials at different depths, altering fertilizer placements in containers, or using biopesticides can be utilized both in closed greenhouse structures and nursery container production. Generally, organic mulch materials have minimum phytotoxicity and hence can be a good option to control weeds without affecting ornamental plant growth. In addition to the non-chemical control strategies, judicious use of chemicals can also reduce the weed growth in nursery containers. The integration of two or more weed control methods can help to suppress weeds effectively. So, there is an urgent requirement to control weeds for Michigan's nursery and greenhouse crop production via both non-chemical and chemical methods which can be utilized both at greenhouses and nursery operations without affecting herbicide-sensitive ornamental plants. In Christmas tree production weeds also can interfere with tree growth at any stage as they compete with the trees for water, nutrients, and light. However, effective weed control is most important during the first three years after transplanting in the field to maintain tree quality and vigorous growth. Proper selection and application of herbicides during the establishment phase of Christmas tree plantations is crucial as there are chances of phytotoxic effects and tree injuries. Michigan Christmas tree growers rely largely on application of postemergence (POST) herbicides to control weeds. However, repeated applications of the same herbicides have resulted in herbicide-resistance among some of the weed species in Michigan. Common ragweed is one of the major problematic weed species in Christmas tree production fields. To control this weed species, growers have applied herbicides with same modes of action repeatedly over the years. As a result, there are recent reports on common ragweed resistance to clopyralid (Stinger), by some Michigan Christmas tree growers. This project will focus on developing new alternative strategies to control this herbicide-resistant ragweed and also to improve the general weed control method in Christmas tree productionby integratingcultural practices (using organic mulch) with the synthetic herbicide combinations. According to the Michigan Department of Agriculture and Rural Development (2019), Michigan ranks third in the nation for the number of Christmas trees harvested, supplying about two million fresh trees with an annual net value of $30-40 million on the national market each year. In Michigan there are more than 560 Christmas tree farms on a combined 37,000 acres. Hence, it is important to help Michigan Christmas tree growers to increase their success with weed management during the establishment phase of the Christmas tree.Growth of the Michigan Christmas tree sector is largely hampered by the laborious and problematic practices of weed control and the recalcitrant nature of field weeds. Improving the efficiency and profitability of this industry through improved weed control can further increase the economic sustainability supplied by this specialty crop sector and its job creation potential. Overall, this research project is planned to develop new effective and economicweed control strategies with an integrated approach and also to improve the existing weed management methods for the nursery growers, greenhouse operators, and Christmas tree producers. With theimproved weed control strategies, there can be a significant increase in the productivity and profitability of this billion-dollar green industry.

Animal Health Component

70%

Research Effort Categories

Basic

Applied

70%

Developmental

30%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
213	2300	1140	100%

Knowledge Area
213 - Weeds Affecting Plants;

Subject Of Investigation
2300 - Weeds;

Field Of Science
1140 - Weed science;

Keywords

nursery container production

weed management

greenhouse operation

christmas tree production

non-chemical weed control

herbicides

herbicide-resistant weed species

integrated weed management

Goals / Objectives
The major objectives of this project are:1) Determine efficacy of chemical and non-chemical control options for problematic weed species in greenhouses and nurseries.2) Determine the phytotoxicity of ornamental herbicides alone and in different combinations for over the top applications to ornamental species in nurseries and different varieties of Christmas trees during their establishment stage.3) Improve upon established cultural control methods to reduce weed growth in ornamentals and Christmas tree production and develop integrated weed control strategies by combining cultural and chemical practices.4) Identify and characterize herbicide-resistant weed species in nurseries and Christmas tree production, and develop alternative strategies to control the herbicide-resistant weeds.

Project Methods
Objective 1.Greenhouse experiments.A series of greenhouse experiments will be conducted at the Horticulture Teaching and Research Center (HRTC), MSU, on liverwortcontrol. For the non-chemical control, organic mulch materials such as rice hulls, hardwood chips, cocoa hullsor pine barkwill be applied on top of the substrate in nursery containers at different depths of 0.25 to 2 inches. Gemmae of liverwort will be applied over the mulch materials. Percent of container surface covered by liverwort thalli will be visually estimated at 2, 4, 6, 8, 10, and 12 weeks after treatment (WAT). Fresh weight of the liverwort thalli will also be recorded at 12 WAT. For determining the chemical control options, different synthetic and organic herbicides will be evaluated on liverwort. Liverwort will be allowed to grow sufficiently and will be monitored at a regular basis to identify4 growth stages i.e. vegetative thalli stage, gemmae cup formation stage, antheridiophore formation stage, and archegoniophore formation stage. Then three organic and three inorganic/synthetic herbicides will be applied at their labeled rates.Percent postemergence control of each growth stage (visual estimation) will be recorded at 1, 3, 7, 14, 21, and 28 days after treatment (DAT). Percent of the substrate surface covered with liverwort will also be recorded at around 56 to 60 DAT. Data will be analyzed by ANOVA in SAS (9.4) and Fisher's LSDwill used to separate out the means.Nursery trials. Problematic weed species identified at nurseries includepurslane, kik, oxalis, various mustards, various thistles and pigweed species. Field experiments will be conducted atdifferent nurseries in Michigan. The liquid formulations of three new herbicides Tower, Pennant and Dimensionand three older/unevaluated herbicides Dacthal, Devrinol and Trifluralin will be applied at various rates either alone or in different combinations duringdormant and growing seasons of the ornamentals.Weed control ratings will be done by visual estimation based on a 0 to 100% scalemonthly for about 4-5 months. The best herbicide/herbicide combinations will be identified that will provide the highest control of these above-mentioned problematic weed species in nursery crop production. Data will be analyzed by ANOVA in SAS (9.4).Objective 2.Nursery trials. Field trials will be conducted atMichigan nurseries. The phytotoxic effects or the safety of liquid formulations of three new herbicides Tower, Pennantand Dimensionand three older/unevaluated herbicides Dacthal, Devrinoland Trifluralinwill be studied on several species, which will include Hosta, Hemerocallis, Salvia, Pervoskia and/or Hibiscus. These herbicides will be applied at various rates either alone or in combinations.Ornamental plants initial and final growth index [(plant height + plant width at widest point + plant width perpendicular to widest point)/3] will be recorded. Phytotoxicity ratings will be done by visual estimation based on a 0 to 100% scalemonthly for 4-5 months. Data will be analyzed by ANOVA in SAS (9.4).Christmas tree field trials. Field trials will be conducted on four different taxa of 2 to 3 years old Christmas trees. Weed control treatments of POST herbicides and organic mulch may include clopyralid (Stinger), glyphosate (Roundup), oxyfluorfen (GoalTender), oxyfluorfen + glyphosate, clopyralid + oxyfluorfen, organic mulch alone, organic mulch + GoalTender + Roundup, and organic mulch + Stinger + GoalTender.Treatments will be appliedduring establishment phase. A control will also be included which will have no herbicide and no mulch. Christmas tree initial and final growth index [(plant height + plant width at widest point + plant width perpendicular to widest point)/3] will be recorded. Tree injuryratings will be done by visual estimation based on a 0 to 100% scale monthly for about 4 months.Objective 3.Greenhouse experiments.Nursery containers will be filled with substrate. Controlled-release fertilizer will be applied to each of the nursery containers whichwill include four different locations: topdress, sub-dress, incorporation, and dibble.Ornamental plants will be obtained from nurseries based on their taxa availability and will be potted during the fertilizer placements incontainers. Control without fertilizer will be included as well.After2 days, gemmae of liverwort will be applied on top of the substrate in each container. All containers will receive irrigation dailyinside the greenhouse. There will be four replications per treatment in a completely randomized design. Percent of container surface covered by liverwort thalli will be visually estimated at 2, 4, 6, 8, 10, and 12 WAT. Fresh weight of the thalli will also be recorded at 12 WAT. Data will be analyzed by ANOVA in SAS (9.4) and Fisher's LSDtest will be used to separate out the means.Christmas tree field trials.Combining herbicides along with mulch materials will be evaluated for weed control efficacies in field trials on four different taxa of 2 to 3-year-old Christmas trees during their establishment stage. Weed control treatments of POST herbicides and organic mulch may include clopyralid, glyphosate, oxyfluorfen, oxyfluorfen + glyphosate, clopyralid + oxyfluorfen, organic mulch alone, organic mulch + GoalTender + Roundup, and organic mulch + Stinger + GoalTender.Controls will also be included which will have no herbicide and no mulch. Data collection will include weed control ratings on individual weed speciesby monthly visual estimation based on a 0 to 100% scale.All data will be analyzed by ANOVA in SAS (9.4) and Fisher's LSDtest will be used to separate the means.Objective 4.Ragweed container trial.An efficacy trial will be conducted at the HTRC, MSU in order to determine alternative control strategies for managing common ragweed. Resistantragweed seeds will be collected from different locations. In this trial nursery containerswill be filled with substrate and then common ragweed seedswill be sown. After the common ragweed has grownto 4 inches in height, weed control treatments [which may include clopyralid (Stinger), glyphosate (Roundup), oxyfluorfen (GoalTender), oxyfluorfen + glyphosate, clopyralid + oxyfluorfen, organic mulch alone, organic mulch + GoalTender + Roundup, and organic mulch + Stinger + GoalTender] will be applied. Control pots will also be included, which will have no herbicide and no mulch. Data collection will include visual estimation of percent coverage in container by ragweed species at 2, 4, 6, 8, 10, and 12 WAT and ragweed fresh weight at 12 WAT.All data will be analyzed by ANOVA in SAS (9.4).Other experiments will be conducted to identify new herbicide-resistant weed species in Christmas tree production.Efficacy trial followed by the dose-response trialwill be conducted to confirm the resistant biotypes. Further studies will be conducted to develop new alternative strategies to control the identified herbicide-resistant weed species.Nursery trials. Trials will be also conducted at different nurseries of Michigan to study nursery herbicide weed resistant species. In these trials different herbicide applicationswill be studied for tolerance to herbicides known to be present in common weed species in Midwest agriculture row crops, and to evaluate their existence in Michigan nursery fields.The results of each of these research trials will be submitted in peer-reviewedjournals such as HortTechnology, Weed Technology. Resultswill be also published in professional and trade journalssuch asMichigan LandscapeandGreat Lakes Christmas Tree journal. Research outcomes will also be publishedin MSUExtensionarticles and fact sheets. Presentations will be made at state, national and international scientific, professional and growers' meetings such as Great Lakes Trade Expo, American Society for Horticultural Sciences, Weed Science Society of America, and International Christmas Tree Research and Extension Conference.

Progress 08/01/20 to 09/30/20

Outputs
Target Audience:The target audience for this program includes nursery growers, greenhouse operators and production managers and others producing container and/or field grown ornamental plants, professional lawn care or pest management professionals in the landscape service industry, Christmas tree growers (both container/field grown), extension educators, extension faculty, scientific community, and even homeowners. Efforts include mostly extension and outreach activities. Four oral presentations were offered at extension related meetings in Michigan, out of which one was presented at the Great Lakes Trade Exposition, organized by Michigan Nursery and Landscape Association in Lansing, MI. One presentation was offered through webinar conducted by Michigan State University. Over ten phone calls and emails consultations answering questions on weed management in ornamentals were made. Visits to eleven different nurseries and greenhouse operations at different regions of Michigan were made in collaboration with the extension educators for consultations on weed management. Apart from extension and outreach, efforts also included formal educational programs. Three guest lecturing were offered at undergraduate level courses on weed management techniques in ornamental horticulture. Changes/Problems:Due to the COVID-19 pandemic outbreak, nursery field trials which were supposed to be conducted at three different nurseries of Michigan to achieve objectives 1 and 2 were cancelled. Instead an outdoor nursery container trial is now being conducted at the on-campus facility, HTRC, MSU for achieving these objectives. Travel to these nurseries were cancelled for the safety of our students and staff. What opportunities for training and professional development has the project provided?Manjot Kaur Sidhu (Ph.D. student), and Carolyn Fitzgibbon (BS, part-time technical aide) gained experience by setting up experiments, conducting and managing trials, and collecting data. They were provided training in greenhouses, nursery environments, and also in laboratory. Manjot Kaur Sidhu (Ph.D. student) participated in national conference, America Society for Horticultural Sciences to present the research results in form of poster and three-minute oral presentations. Manjot has also co-authored in two peer-reviewed journal articles and one extension article. Carolyn Fitzgibbon has co-authored one extension bulletin publication. How have the results been disseminated to communities of interest?In this one year period, results have been disseminated via three oral presentations made at extension related conferences/seminars, one presentation at the plant trial field day organized by Michigan State University, one presentation at the webinar organized by Michigan State University, and about eleven field consultations and ten phone/email consultations were conducted for growers in Michigan, United States. In these presentations, field days, webinar, and field/phone/email consultations information was shared from my research program on ways in which weed control can be more effective, environment-friendly, and less expensive in order to increase the ornamental crop productivity, marketability, and profit margins. Research results were also disseminated at professional meeting, American Society for Horticultural Sciences via oral as well as poster presentations. Results were also shared by means of peer-reviewed journal articles (2), extension articles (8), extension factsheet/bulletins (3), trade journal articles (6). What do you plan to do during the next reporting period to accomplish the goals?We plan to continue our work in each project objective area. Specific objectives for 2021 will be to 1) To determine the phytotoxicity and safety of herbicides alone and in combinations for over the top applications to different varieties of Christmas tree during establishment stage; 2) To improve cultural practices for weed control by altering strategic fertilizer placements in container ornamental production; 3) To improve cultural practices for weed control by organic mulch applications in Christmas tree production; 4) To develop alternative strategies to control clopyralid (Stinger) herbicide resistant ragweed for Christmas tree and nursery production.

Impacts
What was accomplished under these goals? Impact:The major impact of this project objectives was to develop and improve the weed management techniques for the nursery growers, greenhouse operators, and Christmas tree producers. With the improvement in weed control techniques, the growers can improve the productivity, quality, and market value of their ornamental crops. The billion-dollar green industry can improve and have a better profit margins with the improvement in weed control strategies. Major activities completed: Greenhouse trial: A greenhouse experiment is going on at the Horticulture Teaching and Research Center (HTRC), Michigan State University (MSU) to achieve objectives 1 &2. In this experiment 1gallon nursery containers were filled up with standard substrate and was amended with Osmocote controlled release fertilizer. Ornamental plants, Hosta sp were potted immediately. Hostas were obtained from a cooperating liner nursery, Walter Gardens, MI. Two varieties of Hosta sp namely, Curly fries and Pandora box were used in this experiment. For the first round of experiment, Hosta sp. Curly fries variety were potted and for the second round Hosta sp. Pandora box variety were potted. After potting the Hostas, either rice hull (RH) or hardwood chips (HW) or cocoa hull (CH) or pine bark (PB) were applied on top of the substrate in each container at a depth of either 0.25 or 0.5 or 1 or 2 inches. Control set without any mulch materials was included as well. Containers were irrigated 0.4 inches of irrigation via overhead sprinkles inside the greenhouse daily. After 2 days, gemmae of common liverwort (Marchantia polymorpha) were applied over the mulch materials and the substrate (for control set up) in each container. Further application of gemmae is being continued at bi-weekly basis to each container. Gemmae were collected by first scaping gemmae cups of vigorous common liverwort stock plants and releasing the gemmae into a 250 ml bowl of tap water where they will separate out from their clumps. A plastic spoon was used to apply approximately 5 ml (1 tsp) water from the bowl, which contained the gemmae, across the surface of each container. All containers are receiving irrigation daily of approximately 0.4 inches via overhead sprinkler inside the greenhouse. There are four replication per mulch material and depth consisting of a complete randomize design. Currently, data collection is going on which will include visual estimation of liverwort thalli on 2, 4, 6, 8, 10, and 12 weeks after treatment (WAT) and fresh weight of liverwort on 12 WAT. Growth indices of the Hosta sp will be recorded at the beginning and at 12 WAT to determine the phytotoxicity. Manjot Kaur Sidhu (graduate student) has been working to set up the experiment and is also collecting the data by visual estimation of liverwort coverage in each container and Carolyn Fitzgibbon (part-time technical aide) has been helping in setting up the experiment by filling containers and potting up Hostas and maintaining general cleanliness of the greenhouse. The greenhouse experiment is expected to be completed by mid-fall and then data analysis will be done in SAS (9.4). A laboratory experiment to measure the percent moisture retention by four different mulch materials will be conducted towards the end of Fall 2020 or early Spring 2021 to achieve objective 1. Outdoor nursery trial: An outdoor nursery container trial is going on at the HTRC, MSU to achieve objective 1. One and half gallon nursery containers were filled with standard bark-based substrate amended with Osmocote controlled release fertilizer. Then 25 seeds of either Large crabgrass (Digitaria sanguinalis) or common ragweed (Ambrosia artemisiifolia) were sown.These two weed species were selected as they are common problematic weeds in nurseries. After sowing the weed seeds, preemergence herbicides including liquid formulations of three new herbicides Tower (dimethenamid-P), Pennant (s-metolachlor) and Dimension(dithiopyr) and three older/unevaluated herbicides Dacthal (DCPA dimethyl tetrachloroterephthalate), Devrinol (napropamide) and Trifluralin (trifluralin) were applied at various rates either alone or in different combinations via backpack sprayer. All the containers were placed in an outdoor condition where they are receiving irrigation of 0.5 inches via overhead sprinklers daily. There are four replication per treatment consisting of a complete randomize design. Currently, data collection is going on which includes weed counts at 2, 4, 6, 8, 10, and 12 WAT and the weed fresh weight will be recorded at 12 WAT as well. Manjot Kaur Sidhu and Carolyn Fitzgibbon have been working on this experiment. This outdoor nursery container trial is expected to be completed by end of Fall 2020. Then data analysis will be done in SAS (9.4). Initially, the above-mentioned outdoor nursery trial was planned to be conducted at three different nurseries of Michigan. However, Due to COVID-19 pandemic outbreak, the travel plan was cancelled, and we are currently conducting the trial at on-campus HTRC, MSU, facility for the safety of our students and staff. This is the progress report of first year when we have started our trials and experiments in the middle of the COVID-19 pandemic outbreak. Both trials were initiated to achieve objectives 1 and 2 and are still going on. As the project progresses, we will be able to complete data collection and analyze the data to come to a definite conclusion or outcome. In this progress report we are mostly focusing on reporting major activities completed and in our later progress reports or in the final report of this project we will emphasize in reporting accomplishments and key outcomes.

Publications

Type: Journal Articles Status: Published Year Published: 2020 Citation: Sidhu, M.K., R. Lopez, S. Chaudhari, and D. Saha. 2020. A review on common liverwort control in nurseries and greenhouses. HortTechnology https://journals.ashs.org/horttech/view/journals/horttech/aop/article-10.21273-HORTTECH04652-20/article-10.21273-HORTTECH04652-20.xml
Type: Journal Articles Status: Published Year Published: 2020 Citation: Saha, D., H. Lindberg, and M.K. Sidhu*. 2020. Weed ID: Learn how to manage liverwort in nurseries and greenhouses. Nursery Management http://magazine.nurserymag.com/article/august-2020/weed-control-managing-liverwort-weed-id.aspx.
Type: Journal Articles Status: Published Year Published: 2020 Citation: Saha, D. 2020. Top Three Problematic Weeds of Michigan Nursery Container Production. The Michigan Landscape 63 (3):25-28.
Type: Journal Articles Status: Published Year Published: 2020 Citation: Saha, D. 2020. Managing birdeye pearlwort in Michigans nursery container production. The Michigan Landscape 63 (2):48-51.
Type: Journal Articles Status: Published Year Published: 2020 Citation: Saha, D. 2020. Chemical weed control strategies for nurseries and landscapes: Part II. The Michigan Landscape 63 (1):44-46.
Type: Journal Articles Status: Published Year Published: 2020 Citation: Saha, D. 2019.Nonchemical weed control strategies for nurseries and landscapes: Part I. The Michigan Landscape 62 (6):39-41.
Type: Journal Articles Status: Published Year Published: 2020 Citation: Saha, D. 2019. Top three problematic weeds of Christmas tree plantations in great lake regions. Great Lakes Christmas Tree Journal 15 (4): 28-30.
Type: Books Status: Under Review Year Published: 2020 Citation: Saha, D. and J. Landis. 2020. An IPM pocket guide for weed identification in nurseries and landscapes. Michigan State University Extension.
Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Saha, D. 2020. How to manage weeds in ornamental crop production? Plant Trial Field Day. Virtual online session, August 4. (Oral presentation)
Type: Conference Papers and Presentations Status: Awaiting Publication Year Published: 2020 Citation: Saha, D. 2020. Current methods of liverwort control for Michigan nursery growers. MSU Extension Winter Nursery Meeting. (Webinar presentation)
Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Saha, D. 2020. Controlling problem and invasive weeds. Michigan Christmas Tree Association Winter Meeting. Mt. Pleasant, MI, March 6. (Oral presentation)
Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Saha, D. 2020. Glyphosate risk and use. Michigan Christmas Tree Association Winter Meeting. Mt. Pleasant, MI, March 6. (Oral presentation)
Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Saha, D. 2020. Influence of physical and chemical properties of common landscape mulch on weed control efficacy. Great Lake Trade Exposition by Michigan Nursery and Landscape Association. Lansing, MI, January 28. (Oral presentation)
Type: Conference Papers and Presentations Status: Awaiting Publication Year Published: 2020 Citation: Saha, D., C. Marble, N. Boyd, and S. Steed. 2020. How preemergence herbicide formulation can impact weed control efficacy and cost in nursery container production? American Society for Horticultural Sciences, virtual online session, August 13. (Oral presentation)
Type: Conference Papers and Presentations Status: Awaiting Publication Year Published: 2020 Citation: Sidhu, M.K. and D. Saha. 2020. Controlling liverwort (Marchantia polymorpha) in ornamental crop production: A potential research area. American Society for Horticultural Sciences, virtual online session, August 11. (Poster)
Type: Other Status: Published Year Published: 2020 Citation: Saha, D. and C. Fitzgibbon. 2020. Identifying and managing common groundsel (Senecio vulgaris L.) in nurseries and greenhouses. Michigan State University Extension bulletin E3440.
Type: Other Status: Published Year Published: 2020 Citation: Saha, D. and H. Lindberg. 2020. Identifying and Managing Yellow Woodsorrel (Oxalis stricta L.) in Nurseries and Greenhouses. Michigan State University Extension bulletin E3440.
Type: Other Status: Published Year Published: 2020 Citation: Saha, D., H. Lindberg, and M.K. Sidhu*. 2020. Identifying and managing liverwort in Michigan nurseries and greenhouses. Michigan State University Extension https://www.canr.msu.edu/resources/identifying-and-managing-liverwort-in-michigan-nurseries-and-greenhouses
Type: Other Status: Published Year Published: 2020 Citation: Saha, D. 2020. How to identify and manage common groundsel in nurseries and greenhouses. Michigan State University Extension. https://www.canr.msu.edu/news/identify-and-manage-common-groundsel-in-nurseries-and-greenhouses
Type: Other Status: Published Year Published: 2020 Citation: Saha, D. 2020. How to manage field bindweed in Christmas tree production-Part 2. Michigan State University Extension. https://www.canr.msu.edu/news/how-to-manage-field-bindweed-in-christmas-tree-production-part-2
Type: Other Status: Published Year Published: 2020 Citation: Saha, D. 2020. How to identify field bindweed in Christmas tree production-Part 1. Michigan State University Extension. https://www.canr.msu.edu/news/how-to-identify-field-bindweed-in-christmas-tree-production-part-1
Type: Other Status: Published Year Published: 2020 Citation: Saha, D., and E. Hill. 2020. Weed management strategies in greenhouses- Part 2: Chemical weed control strategies. Michigan State University Extension. https://www.canr.msu.edu/news/weed-management-strategies-in-greenhouses-part-2
Type: Other Status: Published Year Published: 2020 Citation: Saha, D., E. Hill, and H. Lindberg. 2020. Weed management strategies in greenhouses- Part 1: Non-chemical weed control strategies. Michigan State University Extension. https://www.canr.msu.edu/news/weed-management-strategies-in-greenhouses-part-1
Type: Other Status: Published Year Published: 2020 Citation: Saha, D. and H. Lindberg. 2020. How to identify and manage yellow woodsorrel in nurseries and greenhouses. Michigan State University Extension https://www.canr.msu.edu/news/how-to-identify-and-manage-yellow-woodsorrel-in-nurseries-and-greenhouses
Type: Other Status: Published Year Published: 2020 Citation: Saha, D., H. Lindberg, and M.K. Sidhu*. 2020. How to identify and manage liverwort in nurseries and greenhouses. Michigan State University Extension https://www.canr.msu.edu/news/how-to-identify-and-manage-liverwort-in-nurseries-and-greenhouses
Type: Other Status: Published Year Published: 2020 Citation: Saha, D. 2019. Birdeye pearlwort in conifer seedling nurseries in Michigan. https://www.canr.msu.edu/news/birdeye-pearlwort-in-conifer-seedling-nurseries-in-michigan