Source: UNIVERSITY OF VERMONT submitted to
EVALUATION OF COMMON MILKWEED AS A NEW FIBER CROP AND NATIVE POLLINATOR ENHANCER
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
HATCH
Reporting Frequency
Annual
Accession No.
1010488
Grant No.
(N/A)
Project No.
VT-H02304
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Oct 1, 2016
Project End Date
Sep 30, 2020
Grant Year
(N/A)
Project Director
Darby, HE, MA.
Recipient Organization
UNIVERSITY OF VERMONT
(N/A)
BURLINGTON,VT 05405
Performing Department
Plant & Soil Science
Non Technical Summary
Many factors are challenging our food system today including climate change, increasing population, and loss of biodiversity. It is estimated that production of 35% of the world's most important food crops rely on insect pollination for productivity. In the last decade, severe declines in pollinator populations have been observed across the world which can be largely attributed to decreases in habitat and agricultural practices. One way of protecting our pollinators is by providing pollinator habitat. Milkweed has been a plant of focus as it is the sole food source for monarch butterfly larvae. Farmers in Vermont are not willing to convert acres of valuable crop land into milkweed for pollinators. However, a textile company in Quebec, Canada has developed a market for the milkweed floss and is looking for the acreage of commercial milkweed production to expand into Vermont. The opportunity would greatly benefit Vermont farmers as planting milkweed could be much more profitable than other row crops and, being a long lived perennial crop, could mitigate negative environmental impacts associated with tillage and nutrient runoff. This project aims to identify effective methods of establishing milkweed as a commercial crop and to investigate the pollinator community that utilizes milkweed in Vermont.
Animal Health Component
0%
Research Effort Categories
Basic
0%
Applied
100%
Developmental
0%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2051799106070%
1361599113020%
2132299114010%
Knowledge Area
136 - Conservation of Biological Diversity; 205 - Plant Management Systems; 213 - Weeds Affecting Plants;

Subject Of Investigation
1799 - Fiber crops, general/other; 2299 - Miscellaneous and new crops, general/other; 1599 - Grain crops, general/other;

Field Of Science
1060 - Biology (whole systems); 1130 - Entomology and acarology; 1140 - Weed science;
Goals / Objectives
There is little agronomic research on how to establish and produce milkweed as a crop. In 2015, NWCS planted a pilot project and found how difficult it was to establish this crop. It is unclear what field preparation may be required, if milkweed can be established with no-till practices, what diseases and insect pests might exist, and which native pollinators will benefit. Although the market exists and there is a lot of interest from farmers to grow the crop, research is needed to understand all the aspects of milkweed cultivation if it is to be a successful crop in Vermont.The goal of this project is to develop a set of standards for successfully establishing milkweed from seed for commercial production.1. Determine the feasibility of planting milkweed using no-till production techniques into rolled and crimped stands of cover crops.We hypothesize that the rolling and crimping method will be effective at limiting weed pressure, allowing the milkweed to emerge without competition. In addition to reducing weed pressure, the use of cover crops over the winter will hold soil and nutrients that could otherwise be lost to the soil and become pollution in surface waters. By using a no-till system, soil structure and health are also preserved. 2. Determine the feasibility of using buckwheat as a nurse crop for establishing milkweed.The major barrier to establishing milkweed is weed pressure. The seed is very slow to germinate in the spring and consequently the plants emerge much after other weeds have had plenty of time to establish. In other perennial crop systems, such as hay production, a nurse or companion crop can be planted with the cash crop. The nurse crop will grow with the cash crop preventing the establishment of weeds. 3. Determine what pollinators and potential pests visit the milkweed crop throughout the growing season and how their visitation timing aligns with the crop management system.Since milkweed is such a critical source of food for the monarch butterfly and other pollinators, harvesting the plant material creates questions about the impact on the pollinators. Although we know that the harvest occurs late in the fall after most of the leaves on the plant have senesced and pollinators are no longer visiting the plant, we do not have in-season management guidelines yet developed for the crop.
Project Methods
Objective 1: Determine the feasibility of planting milkweed using no-till production techniques into rolled and crimped stands of cover crops.This research will take place at Borderview Research Farm in Alburgh, Vermont. To determine the feasibility of planting milkweed into killed cover crops using no-till methods, a field trial will be initiated in the fall of 2016 and repeated in 2017. The experimental design will be a randomized complete block with 4 replications. Treatments will include a winter rye cover crop terminated through tillage, a winter rye cover crop terminated with rolling and crimping, and standard tillage. A winter rye cover crop will be planted in the fall (150 lbs/acre) and allowed to continue growing into the spring of 2017. The cover crop will be terminated using a roller crimper or through traditional tillage techniques. The roller crimper implement is mounted on a tractor and driven over the cover crop. The metal ribs on the large cylinder apply pressure to the stems of the rye bending or "crimping" it as it is bent flat along the soil surface, creating a mat of dying vegetation. The crimped stem keeps the plant from standing back up and blocks water transport through the plant vasculature. This effectively kills the cover crop.In early June, a no-till drill will then be used to plant the milkweed (3 lbs/acre) into the soil through the dense mat of vegetation or into the tilled soil. Weed pressure and milkweed populations will be measured in 1m x 1m quadrates at 1, 2, 3, and 4 months following planting. Soil temperature and soil respiration will be measured at each collection. At the same time plots will be scouting using appropriate protocols for arthropod and disease incidence. At the end of the season total weed biomass will be collected from the 1m x 1m quadrats. During the following spring, the trials will be monitored again for time of bud emergence, winter survival, and populations. When follicles are produced, 20 random plants will be selected from the trial area. The number and length of the follicles on each of the 20 selected plants will be measured and recorded. A full harvest of the plots will occur and yields will be measured.Objective 2: Determine the feasibility of using buckwheat as a nurse crop for establishing milkweed.To determine the feasibility of using buckwheat as a nurse crop when establishing milkweed, a field trial will be initiated at Borderview Research Farm in Alburgh, VT in 2017 and repeated in 2018. The major barrier to establishing milkweed is weed pressure. The seed is very slow to germinate in the spring and consequently the plants emerge much after other weeds have had plenty of time to establish. In other perennial crop systems, such as hay production, a nurse or companion crop can be planted with the cash crop. The nurse crop will grow with the cash crop preventing the establishment of weeds. The nurse crop is typically an annual crop that will die with the onset of winter. By the following spring and summer, the perennial crop should then have had enough time and resources to establish its root system and will then be a much stronger competitor with any new weeds. We hypothesize that we can apply this concept to establishing milkweed using buckwheat as the nurse crop. We chose buckwheat due to its ability to germinate and establish a leaf canopy quickly. Buckwheat is commonly used as a smother crop, planted specifically to outcompete weeds prior to a cash crop. In addition, buckwheat itself has nectar producing flowers which will help provide pollinator habitat and food sources while the milkweed is establishing and not producing flowers.The experimental design will be a randomized complete block with 4 replications. The plots will be 10' x 30' in size. Treatments will include milkweed seeded alone, milkweed seeded with 25 lbs/acre of buckwheat, milkweed seeded with 10 lbs/acre of buckwheat. The experiment will be planted the second week of June. Milkweed will be seeded at 3 lbs/acre. Weed, buckwheat, and milkweed populations will be measured in 1m x 1m quadrates at 1, 2, 3, and 4 months following planting. At the same time plots will be scouting using appropriate protocols for arthropod and disease incidence. Buckwheat will be harvested at maturity (August). At the end of the season total weed biomass will be collected from the 1m x 1m quadrats. During the following spring, the trials will be monitored again for time of bud emergence, winter survival, and populations. When follicles are produced, 20 random plants will be selected from the trial area. The number and length of the follicles on each of the 20 selected plants will be measured and recorded. A full harvest of the plots will occur and yields will be measured.Objective 3: Determine what pollinators and potential pests visit the milkweed crop throughout the growing season and how their visitation timing aligns with the crop management system.Since milkweed is such a critical source of food for the monarch butterfly and other pollinators, harvesting the plant material creates questions about the impact on the pollinators. Milkweed is a perennial plant that emerges in early summer. The plant grows vegetative until about July when it begins to flower. This is about the same time that the adult monarch butterflies begin to seek out the milkweed for its nectar and a place to lay their eggs. The eggs hatch and the caterpillars feed on the milkweed. Once the flowers are pollinated, they will wilt and the plant begins to develop seed pods, called follicles, in their place. The contents of these pods(the white, fluffy floss) is what is ultimately wanted for harvest. The pods continue to develop into the fall. During September and October the pods will dry down, the leaves fall off the plant, and the pods crack open releasing the fluffy seeds to be carried off by the wind. It is at this time that the harvest would occur.Although we know that the harvest occurs late in the fall after most of the leaves on the plant have senesced and pollinators are no longer visiting the plant, we do not have in-season management guidelines yet developed for the crop. We have yet to determine how potential management activities during the season could overlap and interfere with pollinator activities. To better understand the pollinators' utilization of the milkweed plant throughout the entire season, the trials used in objectives 1 and 2 will be monitored for pollinator activity.Pollinator surveys will be conducted bi-weekly from July-October. The survey will include net sampling at five locations throughout the trial area each covering 2.32 m2 as well as plant foliar inspections at five randomly selected plants at each of the net sampling locations. Net sampling is a common method of surveying pollinators and was found to be more effective than destructive pan trap methods (Popic et al 2013). The contents of each net will be transferred into a clear holding container so that the insects can be visually identified and recorded before being released. The foliar inspections will take place on five randomly selected plants within each of the five net sampling locations in the trial area. The plant leaves, flowers, and pods will be inspected for insect damage as well as insects that were not captured in the nets, including monarch caterpillars. The stage of the milkweed will be recorded at each sampling. Sampling procedures will be modified as appropriate once preliminary data is collected.Data AnalysisMixed model analysis will be conducted using the mixed procedure of SAS (SAS Institute, 2008). All treatment factors in this experiment will be considered fixed with the exception of replicates. Mean separation among treatments will be obtained using the Least Significant Difference procedure when significant F-tests (P<0.10) are observed.

Progress 10/01/16 to 09/30/20

Outputs
Target Audience:The target audience are farmers in Vermont seeking alternative crops to improve the viability of their farm. The target audience of farmers is relatively broad because milkweed is a crop that could be implemented as an alternative crop on anyvariety of agricultural operation. Most of these farms would have at least 5 acres in production. Over the project period, we worked with farms currently growing milkweed as a commercial crop, new farmers that are ready to plant milkweed, as well as farmers that were interested in the crop. We also worked with 3 start-up businesses located in VT, NY, and WI that were interested in purchasing milkweed floss from local farmers. Lastly, we provided information to agricultural service providers that work with farmers to grow crops. This includes USDA, private crop consultants, and various nonprofits. The total target audience reached during the project period was over 500 farmers and closely related stakeholders. 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?Project results were disseminated to the target audience at 2 field days, 3 workshops, and 3 conferences held throughout the project period. Grower meetings to teach farmers about establishing and harvesting milkweed attracted over 50 attendees. The Annual Crop and Soil Field Day held in July of 2017, 2018, and 2019 attracted over 600 stakehodlers to learn about growing milkweed as a commerical crop. Winter grain conferences allowed researchers to delover information to over 300 members of theagriculturalcommunity in 2017, 2018, and 2019.Research reports were also distributed to online audiences (www.uvm.edu/extensions/nwcrops). What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? 1. Feasibility of no-till establishment of milkweed.To determine the impact of a rolled and crimped stand of winter rye on weed and milkweed establishment, a trial was initiated at Borderview Research Farm in 2017 and 2018. Treatments were winter rye cover crop terminated with a rollercrimper and no cover crop. Plots with the winter rye treatment were seeded using a Sunflower grain drill (Beloit, KS) in the fall of 2016 and 2017 at 110 lbs ac-1. Plots with no cover crop were lightly disked at this time to incorporate any weed biomass. Milkweed was planted at 6 lbs ac-1 . The plots were assessed for milkweed populations in late May. The no cover crop treatment averaged 0.289 plants ft-2 compared to 0.083 plants ft-2 in the rye treatment. However, this difference was not statistically significant. Despite the control treatment having approximately 3.5 times as much milkweed as the rye treatment, the populations were considerably lower than optimal in either treatment as our target population was 0.557 plants ft-2. These treatments were significantly different in terms of fall weed biomass. The rolled rye treatment significantly reduced weed pressure with only 0.574 tons ac-1 dry matter present by the end of the season compared to almost double that in the no cover treatment. 2. Nurse crops to establish milkweed.To determine the impact of adding a nurse crop to assist with milkweed establishment, a trial was initiated in Alburgh, VT in 2017 and 2018. Five nurse crops (annual ryegrass, oats, buckwheat, phacelia, red clover) at two seeding rates (high versus low) were planted with milkweed and compared to establishing milkweed, also at two seeding rates, without an additional nurse crop. The experimental design was a complete randomized block with four replications. The stand was assessed for milkweed populations and biomass, nurse crop biomass, and weed biomass in late-Sep and again in late-May. To do this, the vegetation growing within a 0.25m2 area in each plot was harvested to ground level. This sample was sorted into milkweed, nurse crop, and weed fractions and biomass recorded. The highest biomass producing nurse crop was buckwheat which produced 2.61 tons ac-1. This treatment also produced the lowest weed biomass which was also statistically similar to the oats in terms of weeds. However, no milkweed was found growing with the buckwheat, likely due to competition for sunlight as the buckwheat grew very quickly and to a height of approximately 24 inches. Interestingly, the clover treatment produced the lowest biomass and milkweed was found growing in both low and high seeding rate treatments. Also of interest was the performance of the two milkweed-only seeding rate treatments. The low seeding rate (3 lbs ac-1) is the rate that has been recommended by producers in Quebec, Canada. When seeded alone at this rate, fall milkweed populations of 0.0929 plants ft-2 were observed whereas when the higher seeding rate of 6 lbs ac-1 was used, fall milkweed populations of 0.557 plants ft-2 were observed. Target stand densities for establishment, according to early milkweed research conducted by Dr. Phippen of Western Illinois University, are 24,000 plants ac-1 or 0.550 plants ft-2. The only treatment that achieved this target density was the milkweed seeded alone at the high seeding rate. 3. Nitrogen and potassium fertilizer rates on milkweed production. The nitrogen and potassium rate trials were conducted in 2018 and 2019. Theexperimental design was a randomized complete block design with four replications. Plots 8' x 35' were imposed into an area of milkweed that was established in 2016. Fertilizer treatments ranging from 0 to 150 lbs of nitrogen or potassiumwere hand applied in early June. At the time fertilizer was applied, all milkweed plants were in vegetative stages ranging from one to four pairs of leaves. Plots in both trials were harvested mid-Sep. At harvest, the number of the plants that had pods, and the total number of pods were recorded as well. Plant height and pod length were recorded for 5 randomly selected plants out of the quadrat area. The pods from the 5 plants were then weighed and a subsample dried to determine moisture content. A subset of the pods from each plot were also separated into pod, floss, and seed fractions and weighed.Fertility treatments did not significantly affect yield or many of the other harvest characteristics in either trial. The number of pods per plant averaged 2.85 and 2.84 with 60.4% and 48.9% of plants having formed pods in the nitrogen and potassium trials respectively. The total pod yields, expressed on a dry matter basis, were 0.893 and 0.776 tons ac-1 for the nitrogen and potassium trials respectively. Treatments also did not differ significantly in terms of pod composition across either trial. The majority of the total pod weight is composed of external pod cover as this was found to be 59.9% and 60.2% for the nitrogen and potassium trials, respectively. The floss, as to be expected, accounted for the smallest fraction at only 17.4% and 16.9% of the total pod weight for the nitrogen and potassium trials, respectively. 4. Chemcial weed control in milkweed. To investigate the impact of chemical weed control on milkweed productivity, an herbicide trial was implemented in an establishedmilkweed stand. Prior to herbicide application, weed composition and ground cover were measured in each plot. This was done by visually identifying the weed species present in each plot and by using the beaded string method (Sloneker and Moldenhauer, 1977). In early-May a treatment of Roundup® was applied to treatment plots. Plots were 20' x 20' in area. Once the milkweed had emerged, plant populations were measured in each plot by counting the number of plants in two 0.25m2 quadrats. The trial was harvested on 16-Sep. Plots were harvested as described above. These data also suggest that one singular spring application of herbicide did not increase milkweed floss yield despite lowering weed pressure. These data are representative of only one location and year. Further investigation is needed to determine optimal and economical fertility rates and weed control methods for milkweed.Impact of herbicide use on milkweed stand productivity Weed control treatments did not significantly affect yield and most harvest characteristics. The number of pods per plant averaged 2.41 with 60.2% of plants on average having pods. Pods averaged 9.29cm in length and plants averaged 75.8cm in height at the time of harvest. The total pod yield, expressed on a dry matter basis, was 0.768 tons ac-1. 5. Pollinators and pests of milkweed.Overall, milkweed bloom lasted from 26-Jun to 10-Jul in 2018 and 10-Jul to 24-Jul in 2019. Phenology of milkweed bloom at Borderview was approximately one week before Dewing for both years. We observed monarch eggs, larvae and adults at both Dewing and Borderview sites throughout the sample period in both 2018 and 2019. In 2018, monarch presence waned significantly by the end of August. In 2019, monarch presence was observed through the first week of September. Due to annual differences in phenology, we suggest annual scouting for monarch presence prior to milkweed harvest through the first few weeks of September. In 2018 and 2019, we surveyed both sites weekly during milkweed bloom for pollinator presence with a focus on bees. During observational surveys in both years, honey bees (Apis mellifera) were the most predominant visitor of milkweed flowers followed by worker bumble bees (Bombus spp.).Based on pest scouting results, presence for all pests were below recommended threshold for treatment. Aphid presence peaked during the pre-bloom period. The average number of aphids across the entire sampling period was 0.20 aphids/8 inches of terminal growth (sd: 0.91).We did not observe any plants with aphid levels that would require further action.

Publications

  • Type: Other Status: Published Year Published: 2017 Citation: Darby, Heather; Ziegler, Sara; Gervais, Amanda; Gupta, Abha; and Ruhl, Lindsey, "Milkweed Production Trials" (2017). Northwest Crops & Soils Program. 84. https://scholarworks.uvm.edu/nwcsp/84
  • Type: Other Status: Published Year Published: 2018 Citation: Darby, H., S. Ziegler, J. Bruce, A. Gupta, and L. Ruhl. 2018. 2018 Milkweed Production Trials. https://www.uvm.edu/sites/default/files/media/2018_Milkweed_Production_Trials_Combined_Rpt.pdf
  • Type: Other Status: Published Year Published: 2019 Citation: Darby, H., S. Ziegler, J. Bruce, I. Luke, and L. Ruhl. 2019. 2019 Milkweed Production Trials. https://www.uvm.edu/sites/default/files/media/2019_Combined_Milkweed_Report.pdf
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Alger, S. (2019, October 17) Pollinators and pests of commercially grown milkweed. [On-farm workshop presentation]. Beginning Milkweed: Cropping and Conservation Considerations, Brownsville, VT (research trial summary handout also created and distributed but not published online)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Nicholson, C. (2018, July 26) Presentation of research results and afternoon session on pollinators [Conference presentation]. 11th Annual Northwest Crops and Soils Field Day, Alburgh, VT, United States. https://www.uvm.edu/sites/default/files/media/Milkweed_RickettsLab.pdf
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Alger, S. (2019, March 28) Pollinator Decline [Conference presentation]. 15th Annual Grain Growers Conference, Essex, VT, United States.


Progress 10/01/18 to 09/30/19

Outputs
Target Audience:The target audience are farmers in Vermont seeking alternative crops to improve the viability of their farm. The target audience of farmers is relatively broad because milkweed is a crop that could be implemented as an alternative crop on any variety of agricultural operation. Most of these farms would have at least 5 acres in production. This project period we worked with farms currently growing milkweed as a commercial crop, new farmers that are ready to plant milkweed,as well as farmers that were interested in the crop. The total target audience reached during the reporting period was 225farmers and closely related industry representatives. 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?Project results were disseminated to the target audience at the University of Vermont Annual Crop and Soil Field Day held in July of 2019 and a Introduction to Growing Milkweed held in Novermber of 2019. The research results were distributed to over 225 attendees at these events. Attendees were able to tour research plots and hear about the preliminary results available. A grower meeting was held in November of 2019 to learn about growing techniques. Research reports were also distributed to online audiences (www.uvm.edu/extensions/nwcrops). What do you plan to do during the next reporting period to accomplish the goals?Project results from the 2019growing season will be compiled and results will be presented at a professional meeting. A publication is being compiled for submission in 2020.

Impacts
What was accomplished under these goals? Milkweed fertility trials-nitrogen and potassium The experimental design in each trial was a randomized complete block design with four replications. Plots 8' x 35' were imposed into an area of milkweed that was established in 2016. Fertilizer treatments were hand applied on 7-Jun in both trials. At the time fertilizer was applied, all milkweed plants were in vegetative stages ranging from one to four pairs of leaves. Plots were also assessed for milkweed populations, height, and flowering status at the time the fertilizer treatments were implemented and again at harvest. The nitrogen was applied in the form of urea (46-0-0) while potassium was applied in the form of muriate of potash (0-0-60). Plots in both trials were harvested on 16-Sep. At harvest, milkweed populations were determined by counting the number of plants within a 0.25m2 quadrat. The number of the plants that had pods, and the total number of pods were recorded as well. Plant height and pod length were recorded for 5 randomly selected plants out of the quadrat area. The pods from the 5 plants were then weighed and a subsample dried to determine moisture content. A subset of the pods from each plot were also separated into pod, floss, and seed fractions and weighed. Impact of herbicide use on milkweed stand productivity To investigate the impact of chemical weed control on milkweed productivity, an herbicide trial was implemented in a milkweed stand that was established in 2016. Prior to herbicide application, weed composition and ground cover were measured in each plot. This was done by visually identifying the weed species present in each plot and by using the beaded string method (Sloneker and Moldenhauer, 1977). On the 7-May a treatment of Roundup® was applied to treatment plots. Plots were 20' x 20' in area. Once the milkweed had emerged, plant populations were measured in each plot by counting the number of plants in two 0.25m2 quadrats. The trial was harvested on 16-Sep. Plots were harvested as described above. Milkweed fertility trials-nitrogen and potassium Fertility treatments did not significantly affect yield or many of the other harvest characteristics in either trial. The number of pods per plant averaged 2.85 and 2.84 with 60.4% and 48.9% of plants having formed pods in the nitrogen and potassium trials respectively. Pods averaged 9.49 and 9.86 cm in length and 57.7% and 58.8% moisture content at the time of harvest for the nitrogen and potassium trials respectively. The total pod yields, expressed on a dry matter basis, were 0.893 and 0.776 tons ac-1 for the nitrogen and potassium trials respectively.Treatments also did not differ significantly in terms of pod composition across either trial. The majority of the total pod weight is composed of external pod cover as this was found to be 59.9% and 60.2% for the nitrogen and potassium trials, respectively. The floss, as to be expected, accounted for the smallest fraction at only 17.4% and 16.9% of the total pod weight for the nitrogen and potassium trials, respectively. Impact of herbicide use on milkweed stand productivity Weed control treatments did not significantly affect yield and most harvest characteristics. The number of pods per plant averaged 2.41 with 60.2% of plants on average having pods. Pods averaged 9.29cm in length and plants averaged 75.8cm in height at the time of harvest. The total pod yield, expressed on a dry matter basis, was 0.768 tons ac-1. These preliminary data suggest that additional nitrogen or potassium fertilizer at rates between 0-100 and 0-150 lbs ac-1 respectively do not increase milkweed floss yield. The soil test results from the test field indicated levels of soil K considered optimum for most field crops and therefore, fields with very low soil test levels of K may experience a greater yield response to additional fertility applications. In terms of nitrogen, lack of moisture throughout the season likely contributed to lower nitrogen availability in the soil. Lastly, it would be important to evaluate timing of fertility applications to milkweed. Like most crops, greater amounts of nutrients are required as the plant builds biomass and shifts to the reproductive stage. Later applications of nutrients might have a larger impact on milkweed pod yields more so than early spring applications. These data also suggest that one singular spring application of herbicide did not increase milkweed floss yield despite lowering weed pressure. These data are representative of only one location and year. Further investigation is needed to determine optimal and economical fertility rates and weed control methods for milkweed. ?

Publications


    Progress 10/01/17 to 09/30/18

    Outputs
    Target Audience:The target audience are farmers in Vermont seeking alternative crops to improve the viability of their farm. The target audience of farmers is relatively broad because milkweed is a crop that could be implemented as an alternative crop on any variety of agricultural operation. Most of these farms would have at least 25 acres in production. This project period we worked with farms currently growing milkweed as a commercial crop as well as farmers that were interested in the crop. The total target audience reached during the reporting period was 365 farmers and closely related industry representatives. 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?Project results were disseminated to the target audience at the Annual Northern Grain Growers Association Meeting held in March of 2018 and also at the University of Vermont Annual Crop and Soil Field Day held in July of 2018. The research results were distributed to over 365 attendees at these event. Attendees were able to tour research plots and hear about the preliminary results available. A grower meeting was held in September of 2018 to evaluate harvesting techniques. Ther were over 30 attendees from Canada and the USA. Research reports were also distributed. What do you plan to do during the next reporting period to accomplish the goals?Project results from the 2018 growing season will be compiled and results will be summarized in a short research report. The report will be distributed to the agricultural community during the winter of 2018. Studies will be repeated in 2019.

    Impacts
    What was accomplished under these goals? 1. Determine the feasibility of planting milkweed using no-till production techniques into rolled and crimped stands of cover crop To determine the impact of adding a nurse crop to assist with milkweed establishment, a trial was initiated in Alburgh, VT in 2017 and 2018. Five nurse crops (annual ryegrass, oats, buckwheat, phacelia, red clover) at two seeding rates (high versus low) were planted with milkweed and compared to establishing milkweed, also at two seeding rates, without an additional nurse crop. The experimental design was a complete randomized block with four replications. Due to complications in securing the milkweed seed from Monark Cooperative, the trial was planted later than anticipated in 2017 on 23- Jul using a Great Plains Grain Cone Seeder. The stand was assessed for milkweed populations and biomass, nurse crop biomass, and weed biomass on 29-Sep and were again assessed for milkweed populations 22- May 2018. To do this, the vegetation growing within a 0.25m2 area in each plot was harvested to ground level. This sample was sorted into milkweed, nurse crop, and weed fractions. The number of milkweed plants was recorded. The biomass of the milkweed, nurse crop, and weed fractions were also recorded. In the spring the populations were so low that the number of plants was recorded for the entire plot area instead of the individual quadrat areas. On 29-Sep, 68 days after planting, biomass and populations of nurse crops, weeds, and milkweed were evaluated. The highest biomass producing nurse crop was buckwheat which produced 2.61 tons ac-1. This treatment also produced the lowest weed biomass which was also statistically similar to the oats in terms of weeds. However, no milkweed was found growing with the buckwheat, likely due to competition for sunlight as the buckwheat grew very quickly and to a height of approximately 24 inches. Interestingly, the clover treatment produced the lowest biomass and milkweed was found growing in both low and high seeding rate treatments. Also of interest was the performance of the two milkweed-only seeding rate treatments. The low seeding rate (3 lbs ac-1) is the rate that has been recommended by producers in Quebec, Canada. When seeded alone at this rate, fall milkweed populations of 0.0929 plants ft-2 were observed whereas when the higher seeding rate of 6 lbs ac-1 was used, fall milkweed populations of 0.557 plants ft-2 were observed. Target stand densities for establishment, according to early milkweed research conducted by Dr. Phippen of Western Illinois University, are 24,000 plants ac-1 or 0.550 plants ft-2. The only treatment that achieved this target density was the milkweed seeded alone at the high seeding rate. 2. Determine the feasibility of using buckwheat as a nurse crop for establishing milkweed. To determine the impact of a rolled and crimped stand of winter rye on weed and milkweed establishment, a trial was initiated at Borderview Research Farm in 2017 and repeated in 2018. Treatments were winter rye cover crop terminated with a roller-crimper and no cover crop. Plots with the winter rye treatment were seeded using a Sunflower grain drill (Beloit, KS) in the fall of 2016 and 2017 at 110 lbs ac-1. The winter rye was terminated using an I&J Roller Crimper (Gordonville, PA). Plots with no cover crop were lightly disked at this time to incorporate any weed biomass. Due to a delay in securing milkweed seed from Monark Cooperative, the milkweed was planted much later than anticipated on 31-Jul using a Sunflower grain drill (Beloit, KS). Milkweed was planted at 6 lbs ac-1. The plots were assessed for milkweed populations on 26-Sep 2017. This was done by counting the number of milkweed plants present in two 0.25m2 quadrats in each plot. These quadrat areas were revisited on 3-Oct 2017 to assess weed populations and collect weed biomass, and milkweed populations were assessed again in 22-May 2018. In the spring, due to very low populations, the number of plants in the entire plot area was measured instead of the individual quadrat areas. At 57 days after planting, the no cover crop treatment averaged 0.289 plants ft-2 compared to 0.083 plants ft-2 in the rye treatment. However, this difference was not statistically significant. Despite the control treatment having approximately 3.5 times as much milkweed as the rye treatment, the populations were considerably lower than optimal in either treatment as our target population was 0.557 plants ft-2. These treatments were significantly different in terms of fall weed biomass. The rolled rye treatment significantly reduced weed pressure with only 0.574 tons ac-1 dry matter present by the end of the season compared to almost double that in the no cover treatment. 3. Determine what pollinators and potential pests visit the milkweed crop throughout the growing season and how their visitation timing aligns with the crop management system. In order to develop in-season management recommendations for established milkweed stands, we need to understand what pollinators are utilizing milkweed plants throughout the season. To begin to investigate this matter, two milkweed fields established in 2015 and 2016, were surveyed for pollinators 3 times between 3-Jul and 11-Jul. At each sampling, the plants at four locations throughout each field, which had open flowers present, were watched for 10 minutes each. During this time the number of individuals and flower visits for eight morphospecies of pollinators were noted: Apis, Bombus (queens), Bombus (workers), big black bees, slender black bees, tiny black bees, Lepidoptera, wasps, flies, and beetles. Prior to moving to another observation area, the number of open flowers was recorded as well as weather conditions including temperature, wind speed, relative humidity, and sky condition. The flowering status of both milkweed and weeds were also noted by rating on a 0-3 scale where 0 indicated no flowers present and 3 indicated full bloom. An approximate 10m transect was then walked in each field for 10 minutes collecting insects with an insect net. If honey bees were collected with the net the timer was stopped to allow for time to remove the honey bees. After 10 minutes, the insects collected in the net were transferred to a glass kill-jar for preservation and later identification. Finally, to understand bee pollination efficacy of milkweed, a 20m transect was walked for 1 hour or until 20 bees visiting milkweed flowers were located. The bees were collected, identified, and placed in a non-kill glass jar for inspection. The number of pollinia, milkweed pollen structures, stuck to each bee was recorded. The bees were released after data was collected. The timer was stopped while bees were transferred and data was collected. During scouting visits, bees belonging to six different genera were collected through net collections. Of these, honeybees, Apis mellifera were the most abundant, accounting for >95% of witnessed flower visits. This was not surprising given the proximity of these milkweed stands to managed honeybee hives. Additional insects, including butterflies, beetles, flies, and lacewings, visited milkweed flowers but in significantly lower abundance than honeybees. Furthermore, honeybees were the dominant bee species found to be carrying milkweed pollinia. On average, honeybees were carrying 2.25 pollinia. These pollinia were most often found to be attached to the front legs of the bees. The number of honeybees and flower visits in early July peaked at 28.1 individual bees and 112 flower visits. With the decreased number of flowers available in mid-July, the number of honey bees decreased to 2.43 and flower visits to 12.5.

    Publications

    • Type: Other Status: Published Year Published: 2018 Citation: Darby, H. and S. Ziegler. 2018. Milkweed Production Trial. University of Vermont Extension Research Report. http://www.uvm.edu/extension/cropsoil/wp-content/uploads/2017-Milkweed-Production-Trial.pdf


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

    Outputs
    Target Audience:The target audience are farmers in Vermont seeking alternative crops to improve the viability of their farm. The target audience of farmers is relatively broad because milkweed is a crop that could be implemented as an alternative crop on any variety of agricultural operation. Most of these farms would have at least 25 acres in production. This project period we worked with farms currently growing milkweed as a commercial crop as well as farmers that were interested in the crop. The total target audience reached during the reporting period was 350 farmers and closely related industry representatives. 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?Project results were disseminated to the target audience at the Annual Northern Grain Growers Association Meeting held in March of 2018 and also at the University of Vermont Annual Crop and Soil Field Day held in July of 2018. The research results were distributed to over 350 attendees at these event. Attendees were able to tour research plots and hear about the preliminary results available. Research reports were also distributed. What do you plan to do during the next reporting period to accomplish the goals?Project results from the 2018 growing season will be compiled and results will be summarized in a short research report. The report will be distributed to the agricultural community during the winter of 2018. Studies will be repeated in 2019.

    Impacts
    What was accomplished under these goals? 1. Determine the feasibility of planting milkweed using no-till production techniques into rolled and crimped stands of cover crop To determine the impact of adding a nurse crop to assist with milkweed establishment, a trial was initiated in Alburgh, VT in 2017. Five nurse crops (annual ryegrass, oats, buckwheat, phacelia, red clover) at two seeding rates (high versus low) were planted with milkweed and compared to establishing milkweed, also at two seeding rates, without an additional nurse crop. The experimental design was a complete randomized block with four replications. Due to complications in securing the milkweed seed from Monark Cooperative, the trial was planted later than anticipated on 23- Jul using a Great Plains Grain Cone Seeder. The stand was assessed for milkweed populations and biomass, nurse crop biomass, and weed biomass on 29-Sep and were again assessed for milkweed populations 22- May 2018. To do this, the vegetation growing within a 0.25m2 area in each plot was harvested to ground level. This sample was sorted into milkweed, nurse crop, and weed fractions. The number of milkweed plants was recorded. The biomass of the milkweed, nurse crop, and weed fractions were also recorded. In the spring the populations were so low that the number of plants was recorded for the entire plot area instead of the individual quadrat areas. On 29-Sep, 68 days after planting, biomass and populations of nurse crops, weeds, and milkweed were evaluated. The highest biomass producing nurse crop was buckwheat which produced 2.61 tons ac-1. This treatment also produced the lowest weed biomass which was also statistically similar to the oats in terms of weeds. However, no milkweed was found growing with the buckwheat, likely due to competition for sunlight as the buckwheat grew very quickly and to a height of approximately 24 inches. Interestingly, the clover treatment produced the lowest biomass and milkweed was found growing in both low and high seeding rate treatments. Also of interest was the performance of the two milkweed-only seeding rate treatments. The low seeding rate (3 lbs ac-1) is the rate that has been recommended by producers in Quebec, Canada. When seeded alone at this rate, fall milkweed populations of 0.0929 plants ft-2 were observed whereas when the higher seeding rate of 6 lbs ac-1 was used, fall milkweed populations of 0.557 plants ft-2 were observed. Target stand densities for establishment, according to early milkweed research conducted by Dr. Phippen of Western Illinois University, are 24,000 plants ac-1 or 0.550 plants ft-2. The only treatment that achieved this target density was the milkweed seeded alone at the high seeding rate. 2. Determine the feasibility of using buckwheat as a nurse crop for establishing milkweed. To determine the impact of a rolled and crimped stand of winter rye on weed and milkweed establishment, a trial was initiated at Borderview Research Farm in 2017. Treatments were winter rye cover crop terminated with a roller-crimper and no cover crop. Plots with the winter rye treatment were seeded using a Sunflower grain drill (Beloit, KS) in the fall of 2016 at 110 lbs ac-1. The winter rye was terminated using an I&J Roller Crimper (Gordonville, PA). Plots with no cover crop were lightly disked at this time to incorporate any weed biomass. Due to a delay in securing milkweed seed from Monark Cooperative, the milkweed was planted much later than anticipated on 31-Jul using a Sunflower grain drill (Beloit, KS). Milkweed was planted at 6 lbs ac-1. The plots were assessed for milkweed populations on 26-Sep 2017. This was done by counting the number of milkweed plants present in two 0.25m2 quadrats in each plot. These quadrat areas were revisited on 3-Oct 2017 to assess weed populations and collect weed biomass, and milkweed populations were assessed again in 22-May 2018. In the spring, due to very low populations, the number of plants in the entire plot area was measured instead of the individual quadrat areas. At 57 days after planting, the no cover crop treatment averaged 0.289 plants ft-2 compared to 0.083 plants ft-2 in the rye treatment. However, this difference was not statistically significant. Despite the control treatment having approximately 3.5 times as much milkweed as the rye treatment, the populations were considerably lower than optimal in either treatment as our target population was 0.557 plants ft-2. These treatments were significantly different in terms of fall weed biomass. The rolled rye treatment significantly reduced weed pressure with only 0.574 tons ac-1 dry matter present by the end of the season compared to almost double that in the no cover treatment. 3. Determine what pollinators and potential pests visit the milkweed crop throughout the growing season and how their visitation timing aligns with the crop management system. In order to develop in-season management recommendations for established milkweed stands, we need to understand what pollinators are utilizing milkweed plants throughout the season. To begin to investigate this matter, two milkweed fields established in 2015 and 2016, were surveyed for pollinators 3 times between 3-Jul and 11-Jul. At each sampling, the plants at four locations (Figure 3) throughout each field, which had open flowers present, were watched for 10 minutes each. During this time the number of individuals and flower visits for eight morphospecies of pollinators were noted: Apis, Bombus (queens), Bombus (workers), big black bees, slender black bees, tiny black bees, Lepidoptera, wasps, flies, and beetles. Prior to moving to another observation area, the number of open flowers was recorded as well as weather conditions including temperature, wind speed, relative humidity, and sky condition. The flowering status of both milkweed and weeds were also noted by rating on a 0-3 scale where 0 indicated no flowers present and 3 indicated full bloom. An approximate 10m transect was then walked in each field for 10 minutes collecting insects with an insect net. If honey bees were collected with the net the timer was stopped to allow for time to remove the honey bees. After 10 minutes, the insects collected in the net were transferred to a glass kill-jar for preservation and later identification. Finally, to understand bee pollination efficacy of milkweed, a 20m transect was walked for 1 hour or until 20 bees visiting milkweed flowers were located. The bees were collected, identified, and placed in a non-kill glass jar for inspection. The number of pollinia, milkweed pollen structures, stuck to each bee was recorded. The bees were released after data was collected. The timer was stopped while bees were transferred and data was collected. During scouting visits, bees belonging to six different genera were collected through net collections. Of these, honeybees, Apis mellifera were the most abundant, accounting for >95% of witnessed flower visits. This was not surprising given the proximity of these milkweed stands to managed honeybee hives. Additional insects, including butterflies, beetles, flies, and lacewings, visited milkweed flowers but in significantly lower abundance than honeybees. Furthermore, honeybees were the dominant bee species found to be carrying milkweed pollinia. On average, honeybees were carrying 2.25 pollinia. These pollinia were most often found to be attached to the front legs of the bees. The number of honeybees and flower visits in early July peaked at 28.1 individual bees and 112 flower visits. With the decreased number of flowers available in mid-July, the number of honey bees decreased to 2.43 and flower visits to 12.5.

    Publications