Progress 10/01/19 to 09/30/20
Outputs
Target Audience:Growers currently cultivating saffron and those who intend to in the future are the primary target audience. These growers represent a wide array of producers, including small diversified farmers, dairy farmers, nursery and greenhouse operators and new Americans. In addition, home gardeners, and future retirees who seek to supplement their social security with income from saffron. Extension personnel and researchers will be key to dissemination of information on saffron production and pest management practices. Changes/Problems:None What opportunities for training and professional development has the project provided?Continued effort has been expended by the investigators to maintain the Center's listserve, Saffronnet. This listserve has over 700 members. It continues to serve as an excellent tool to use for disseminating our research results and information about saffron production and pest management. Current and future saffron growers were the primary audience at multiple presentations. We gave over 10 presentations on saffron production, reaching over 1,000 growers and agricultural specialists and extension personnel. How have the results been disseminated to communities of interest?In addition to saffronnet, the listserve, a yearly workshop specifically dealing with all aspects of saffron production and marketing was held in March, 2020. Attendance at this worshop totaled >100 growers from all across the U.S. and Canada. Speakers were enlisted from throughout New England, and subjects included weed id and management, post-harvest handling, organic certification and the economics of saffron. A grower to grower session allowed seasoned growers participants to share their saffron production practices and problems. Information on rearing bulb mites was shared with other scientists who are working on this pest, and intend to adopt these methods, for their biological control research. Multiple presentations and factsheets were prepared and given on the value of habitat plantings, reaching at least 1,000 growers, many of whom have adopted this practice which benefits the environment by supporting beneficial arthropods. Presentations were held in several New England states to introduce growers to the potential of growing saffron. What do you plan to do during the next reporting period to accomplish the goals?We will continue to evaluate the efficacy of different plants within habitat strips to attract natural enemies and maintain thrips populations within saffron beds below damaging levels. The predator/prey experiment will be repeated in pot trials. Small mammal damage to corms and flower production will be assessed in July and trials repeated in the coming year. Results of these trials will be reported to growers at the 5th annual saffron workshop anticipated in March 2021. We will continue to maintain Saffronnet and our saffron website, produce factsheets and promote saffron production nationally.
Impacts
What was accomplished under these goals?
Since 2015, our research on production of saffron in Vermont has exploded on the national scene. For this project, our goal is to expand our work by developing strategies to minimize the negative impact of key arthropod and rodent pests on saffron yield and corm survival. We are focused on the following damaging agents: Arthropods: bulb mites and thrips, and Small Mammals: voles and rabbits. We recognize there are other factors impacting yield, including weeds, water relations, fertility and diseases, to name only a few. These are currently beyond the scope of this project but will be addressed in other extramural proposals. The arthropod work for this project links with past Hatch research using plant-mediated IPM systems. This work will further the emerging saffron industry in the US, a high-value crop that will strengthen the economic viability of small family farms, the backbone of our agriculture. Bulb mites, genus Rhizoglyphus (Family Acaridae), are pests of economically important plants including bulbs, corms, and tubers.Bulb mites were observed associated with diseased corms in UVM saffron research sites, confirming their pest status. A standard method to rear bulb mites to ensure a continual supply of test organisms is essential for testing. Over the last 3 years we established a bulb mite laboratory culture. Bulb mites were collected locally and separated by species. They were identified to species, and species identification was confirmed by a Canadian specialist. An innovative mite rearing method was developed and assessed for effectiveness. This involves growing them on potato dextrose agar (PDA) with Choramophenical (antibiotic). The key to successful mite production was maintaining the agar medium at a moisture content of ~67%. Adequate supplies of bulb mites are now available for test purposes using this rearing method. Lab trials were conducted to assess the efficacy of a commercially available soil-dwelling predatory mite (Stratiolaelaps scimitus) to suppress bulb mite populations. Three predator/prey ratios (1:5, 1:10 and 1:15) with five S. scimitus to 25, 50 and 75 R. robini. Predation was assessed after 48 hours. The trial was conducted based on a completely random design (CRD) and the experiment was replicated six times on different dates. Results showed the 1:5 predator:prey ratio yielded mortality of 72.5%, which was significantly greater than the other treatments (1:10: 51.8%; 1:15: 38.2%) and controls (4.4-8.0%). We will replicate the laboratory trials in soil in the laboratory in the future with this rate. These trials will also offer options for managing mites in other crops, such as onions and garlic. Obj. 2. Assess the attractiveness of habitat plants to native natural enemies of thrips infesting saffron. We have found that a wide range of biological control agents known to attack thrips are lured into high tunnels when assemblages of pollen-producing plants (alyssum, dill, borage, etc.) are grown in clumps within the growing area. Two plant species, alyssum and marigolds were planted adjacent to saffron plots and arthropod biodiversity has been monitored over the summer and fall. The percentage of fractional green canopy cover (%FGCC) in the saffron beds will be measured in annually every July. Results will provide insights into the effect of habitat plants on insect pests on saffron and demonstrate the attractiveness of different flowering plants to beneficials. Obj. 3. Determine the efficacy of various IPM tactics for minimizing small mammal damage in saffron plantings. Trials were conducted to assess several approaches to reduce damage to saffron corms from voles and rabbits. Five treatments were tested, 1) crushed oyster sells applied around corms and on the soil surface at planting; 2) rodent repellent sprayed after harvest in the fall and 3 times in the spring; 3) rodent repellent and oyster shells combined; 4) no treatment; 5) hardware cloth around and under saffron beds. Data were collected on the number of flowers, size and number of corms and fractional green canopy cover in spring. Saffron corms were planted in Sept. 2018 and over the next 3 years, the number of flowers, mean % FGCC (leaf density index), number and size of secondary corms/mother corm will be recorded. Significantly more flowers were produced in the second season in all treatments, and no significant differences were observed among treatments. The density of saffron leaves was slightly higher in the oyster shell treatments than the others. No significant differences in the number of secondary corms/mother corm were observed, but significantly larger corms were produced in the oyster shell and spray treatment (8.5 cm circ.) than the other treatments. There were no differences in the number of flowers produced among treatments over the 2 study years. Corms in plots treated with oyster shells were significantly larger than those in control plots, and those in treatment 3 were significantly larger than those in the other treatments. Based on observations of the test plots, spreading crushed oyster shells on the soil surface appeared to reduce damage from both rabbits and voles. Further data to confirm efficacy will be taken in the summer and fall of 2020. Isolation and purification of bulb mites from infested saffron corms and identification. Maintenance of the bulb mite culture continued allowing for further testing. Improved culture medium for bulb mite rearing under laboratory conditions developed. Established predator/prey relationship between S. scimitus and R. robini Saffron corms were planted and the experiment was designed for the small mammal trial to be done over the next 3 years. At several workshops and conferences, specimens of bulb mites, saffron corm diseases, vole and rabbit damage were made available to attendees. Multiple presentations were given reaching over 1,000 attendees, that has led to hundreds of growers starting to produce saffron for the first time. Website updates and listserv reached thousands of growers and researchers involved in saffron production.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Ghalehgolabbehbahani, A., M. Skinner, B.L. Parker, A. Razavi, P. Reese & A. Davari. 2020. A standardized method for rearing Rhizoglyphus robini (Astigmata: Acaridae). J. Plant Dis. Protection.
https://doi.org/10.1007/s41348-020-00381-3
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Progress 10/01/18 to 09/30/19
Outputs
Target Audience:Growers currently cultivating saffron and those who intend to in the future are the primary target audience. These growers represent a wide array of producers, including small diversified farmers, dairy farmers, nursery and greenhouse operators and new Americans. In addition, home gardeners, and future retirees who seek to supplement their social security with income from saffron. Extension personnel and researchers will be key to dissemination of information on saffron production and pest management practices. Changes/Problems:None What opportunities for training and professional development has the project provided?Continued effort has been expended by the authors to maintain the Center's listserve, Saffronnet. This listserve has over 650 members (62% increase from last year). It continues to serve as an excellent tool to use for disseminating our research results and information about saffron production and pest management. Current and future saffron growers were the primary audience at multiple presentations. We gave over 10 presentations on saffron production, reaching over 400 growers and agricultural specialists and extension personnel. How have the results been disseminated to communities of interest?In addition to saffronnet, the listserve, a yearly workshop specifically dealing with all aspects of saffron production and marketing was held in March. Attendance at this workshop totaled >100 growers from all across the U.S. and Canada. Speakers were enlisted from the Netherlands and other parts of Europe where saffron is produced. A grower to grower approach was successful and allowed participants to delve into problems commonly encountered. Information on rearing bulb mites was shared with other scientists who are working on this pest, and intend to adopt these methods, for their biological control research. Multiple presentations and factsheets were prepared and given on the value of habitat plantings, reaching at least 1,000 growers, many of whom have adopted this practice which benefits the environment by supporting beneficial arthropods. Presentations were held in several New England states to introduce growers to the potential of growing saffron. What do you plan to do during the next reporting period to accomplish the goals?We will test the efficacy of different plants within habitat strips to attract natural enemies and maintain thrips populations within saffron beds below damaging levels. The predator/prey experiment will be repeated in pot trials and the results will be reported during the next reporting period. Small mammal damage to corms and flower production will be assessed this spring and trials repeated in the coming year. Results of these trials will be reported to growers at the 4th annual saffron workshop scheduled for March 2020. We will continue to maintain Saffronnet and our saffron website, produce factsheets and promote saffron production nationally.
Impacts
What was accomplished under these goals?
Since 2015, our research on production of saffron in Vermont high tunnels has exploded on the national scene. For this Hatch research, our goal is to expand our work by developing strategies to minimize the negative impact of key arthropod and rodent pests on saffron yield and corm survival. We are focused on the following damaging agents: Arthropods: bulb mites and thrips, and Small Mammals: voles and rabbits. We recognize there are other factors impacting yield, including weeds, water relations, fertility and diseases, to name only a few. These are currently beyond the scope of this project but will be addressed in other extramural proposals. The arthropod work we propose links with past Hatch research using plant-mediated IPM systems. Obj. 1. Determine the efficacy of Stratiolaelaps scimitus, a commercially available soil-dwelling predatory mite, on bulb mites in saffron production. We continue to see bulb mites associated with diseased saffron corms in our VT trials, confirming their pest status in New England saffron. We continued to refine rearing of the Rhizoglyphus robini (bulb mite) colony established in 2018. Further trials were conducted showed that drying the Petri dishes filled with potato dextrose agar (PDA) under a laminar flow hood for 1 mo reduced the moisture content to 67%, which increased mite survival. It was also found that adding antibiotics or a fungicide to the medium had a negative effect on mite populations. Mite populations peaked between 10-20 days after introduction into the Petri dish. Lab trials in Petri dishes were conducted to assess predation of R. robini by Stratiolaelaps scimitus, and it was determined that the predatory mite consumed >30 thrips/day. Three predator/prey ratios (1:5, 1:10 and 1:15) with 5 S. scimitus to 25, 50 and 75 R. robini. Predation was assessed after 48 hours. Results showed the 1:5 predator:prey ratio yielded mortality of 72.47%, which was statistically greater than the other treatments and control. This ratio will be used for the next stage, which is trials with saffron corms in pots, to which predatory and bulb mites are added. Obj. 2. Assess the attractiveness of habitat plants to native natural enemies of thrips infesting saffron. We have found that a wide range of biological control agents known to attack thrips are lured into high tunnels when assemblages of pollen-producing plants (alyssum, dill, borage, etc.) are grown in clumps within the growing area. Over 37% of natural enemies observed in summer were on alyssum, 28% on borage, and 16% on dill. Parasitic wasps were most commonly present. Compared to other plants, alyssum was the least attractive to aphids. We also evaluated habitat strips containing a variety of flowering annuals, including marigolds, coreopsis, Indian blanket, blue cornflower, sunflower, alyssum, zinnia and cosmos. Natural enemies of thrips were observed most often on sunflower, alyssum, zinnia and cosmos. Obj. 3. Determine the efficacy of various IPM tactics for minimizing small mammal damage in saffron plantings. Preliminary trials were conducted with several non-conventional approaches to reduce damage to saffron corms from voles and rabbits. Five treatments were tested, 1) crushed oyster sells applied around corms and on the soil surface at planting; 2) rodent repellent sprayed after harvest in the fall and 3 times in the spring; 3) rodent repellent and oyster shells combined; 4) no treatment; 5 hardware cloth around and under saffron beds. Data number of flowers, size and number of corms and fractional green canopy cover in spring. There were no differences in the number of flowers produced among treatments over the 2 study years. Corms in plots treated with oyster shells were significantly larger than those in control plots, and those in treatment 3 were significantly larger than those in the other treatments. Based on observations of the test plots, spreading crushed oyster shells on the soil surface appeared to reduce damage from both rabbits and voles. Further data to confirm efficacy will be taken in the spring, 2020.
Publications
- Type:
Other
Status:
Published
Year Published:
2019
Citation:
Sullivan, C. Frank & Skinner, M. 2019. Habitat Plantings Harbor Happy Beneficial Bugs. VT Vegetable & Berry Newsletter compiled by V. Grubinger, March, 2019 http://www.uvm.edu/vtvegandberry/Pubs/HabitatPlants.pdf
- Type:
Websites
Status:
Published
Year Published:
2019
Citation:
North American Center for Saffron Research and Development. http://www.uvm.edu/~saffron/
- Type:
Websites
Status:
Published
Year Published:
2019
Citation:
University of Vermont Entomology Research Laboratory, https://www.uvm.edu/~entlab/Landscape%20IPM/LandscapeIPM.html
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Progress 10/05/17 to 09/30/18
Outputs
Target Audience:Growers currently cultivating saffron and those who intend to in the future are the primary target audience. These growers represent a wide array of producers, including small diversified farmers, dairy farmers, nursery and greenhouse operators and new Americans. In addition, home gardeners, and future retirees who seek to supplement their social security with income from saffron. Extension personnel and researchers will be key to dissemination of information on saffron production and pest management practices. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Continued efforts have been expended by the PIs to maintain and support the Saffron Center's listserve, Saffronnet. This listserve has over 400 members and serves as an excellent tool to use for training and development of saffron production methods. The saffron website also provides a source for educational materials produced by the PIs and by others. Hands-on training sessions have been held for growers at the UVM Saffron Center to demonstrate corm planting methods and drying procedures. Several presentations for stakeholders have been given at conferences and workshops. Press releases have been prepared which led to articles in local and national media outlets regarding the potential of saffron as a high value specialty crop. The habitat hedges tested in this project not only attracted lots of beneficials, they also provided several educational opportunities for inquiring customers and students. High school students and graduate students visiting from the American University of Beirut, Lebanon learned firsthand the benefits of these eco-niches. All were taught how to create these bug-friendly habitats and distinguish the good bugs from the bad ones. The Lebanese students, who took part in an IPM training course at the UVM Entomology Research Lab, brought this knowledge back to Lebanon to help farmers reduce their reliance on chemical pesticides and adopt more sustainable agricultural practices. How have the results been disseminated to communities of interest?In addition to Saffronnet, and the Saffron Center website, for the past two years a workshop specifically dealing with aspects of saffron production and marketing has been held in March. Attendance at the 2018 workshop was attended by >100 growers from all across the U.S. and Canada. Speakers were enlisted from the Netherlands where saffron is produced. A grower to grower approach has been successful and allowed participants to delve into problems commonly encountered. Attendees were very satisfied with the program, and encouraged us to continue to hold the event. Several presentations for stakeholders have been given at conferences and workshops. Press releases have been prepared which led to articles in local and national media outlets. What do you plan to do during the next reporting period to accomplish the goals?Obj. 1. Determine the efficacy of Stratiolaelaps scimitus, a commercially available soil-dwelling predatory mite, on bulb mites in saffron production. Now that we have a ready supply of bulb mites for test purposes and have skill handling these small arthropods, the next step is to assess the efficacy of the predatory mite. Replicated trial will be conducted for this to determine the ratio of predators and prey to achieve successful pest suppression. Obj. 2. Assess the attractiveness of habitat plants to native natural enemies of thrips infesting saffron. Field beds of saffron have been established at the University of Vermont Horticultural Research Center. This site will serve as the location for planting habitat bands of annual and perennial flowering plants in 2019. Habitat hedgerows including flowering annuals and perennial plants will be established adjacent to saffron beds to test their efficacy to attract natural enemies and maintain thrips populations within saffron beds below damaging levels. These plantings will serve as attractive environments for pollinators and natural enemies that could contribute to reducing bulb mite and/or thrips populations. Obj. 3. Determine the efficacy of various IPM tactics for minimizing small mammal damage in saffron plantings. Several conventional and non-conventional biological approaches will be tested to determine the most cost effective IPM approach to adopt. For example, oyster shells incorporated to the soil surface and chili pepper suspensions at the side of the beds to discourage voles and rabbits, respectively. Saffron corms were planted early September 2018 at the rate of 8 corms/sq.ft, 6 inches deep at UVM Horticultural Research Farm. The experiment was designed as a randomized complete block design with 5 treatments and 5 replications. Saffron flowers were harvested every two days over the flowering season (October and November). Corms will be sampled in the spring to assess the treatment effects in terms of protecting them from small mammal damage.
Impacts
What was accomplished under these goals?
Since 2015, our research on production of saffron in Vermont high tunnels has exploded on the national scene. For this Hatch research, our goal is to expand our work by developing strategies to minimize the negative impact of key arthropod and rodent pests on saffron yield and corm survival. We will focus on the following damaging agents: Arthropods: bulb mites and thrips, and Small Mammals: voles and rabbits. We recognize there are other factors impacting yield, including weeds, water relations, fertility and diseases, to name only a few. These are currently beyond the scope of this project but will be addressed in other extramural proposals. The arthropod work we propose links with past Hatch research using plant-mediated IPM systems. Obj. 1. Determine the efficacy of Stratiolaelaps scimitus, a commercially available soil-dwelling predatory mite, on bulb mites in saffron production. The first critical step for a successful augmentation program is to identify the pest organism. We located an infestation of bulb mites in saffron grown in a high tunnel in Vermont. Three different species of bulb mites were identified by an acarologist from the Univ. of Michigan (Dr. Barry O'Connor). They were Rhizoglyphus robini, Sancassania anomala and Carpoglyphus lactis. Because R. robini was the most commonly occurring species, we are focusing on this one rather than the other two. To assess the suitability of an augmentative release program using a soil dwelling predatory arthropod, it was necessary to establish a lab colony of the target pest. A rearing method using potato dextrose agar (PDA) was evaluated. Initially we found that high moisture content in the PDA (~82%) trapped the bulb mites. This problem was avoided when the Petri dishes of PDA were allowed to dry until moisture levels of <70% were achieved. Microbial contamination of the PDA also reduced bulb mite populations. We tested PDA alone, PDA with an antibiotic and PDA with an antibiotic and a fungicide. Bulb mites grew best on PDA with an antibiotic. Specifically when 12 mites were placed in a Petri dish with PDA and an antibiotic, within 2 weeks the population increased to 135 mites, an 11-fold increase. Populations decreased in weeks 3 and 4. The reason for the rapid decrease is under investigation. Our ultimate goal is to maintain a culture of the mites for test purposes. Obj. 2. Assess the attractiveness of habitat plants to native natural enemies of thrips infesting saffron. Scientists at the University of Vermont, Entomology Research Laboratory have been working with growers across the state to establish habitat hedges that encourage beneficial arthropods. The suitability of different types of plants in terms of their flowering patterns and ability to attract beneficials were evaluated. These hedges consisted of a variety of annuals, including alyssum, coreopsis, blue cornflower, Indian blanket, cosmos, sunflowers and zinnias. These plants were started from seed or as transplants in late spring. The hedges provided a diversity of floral shapes, sizes and heights throughout the season. A wide range of pest-fighting pollinators and other natural enemies were observed visiting these plantings. Many of these are well-known natural enemies of a broad range of pests, including bulb mites and thrips. Syrphid flies were the most commonly observed beneficial on habitat strips in 2018 (>40%). These are those insects that look like bees, but tend to flap their wings and hover in one place. As adults, these flies are important pollinators in many settings, visiting lots of flowers to feed on pollen and nectar. As immatures, the larvae (maggots) of many species are voracious predators of soft-bodied insects, including thrips. When growers provide flowering plants early during the growing season, these beneficials become established in time to take on their pest prey. Flowers late in the year supply the syrphids with food in the fall that helps them survive over the winter. Results from this work will be used to select suitable plants to include in habitat plantings associated with saffron to combat bulb mites and or thrips. Obj. 3. Determine the efficacy of various IPM tactics for minimizing small mammal damage in saffron plantings. Work on this will begin in Year 2.
Publications
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2018
Citation:
Skinner, M. & A. Ghalehgolabbehbahani. 2018. Saffron: A Golden Opportunity for Small Diversified Farmers. Herb Society of America, Annual Meeting Tarrytown, NY, June 1, 2018. Oral presentation.
- Type:
Other
Status:
Other
Year Published:
2018
Citation:
Skinner, M. & A. Ghalehgolabbehbahani. 2018. Saffron: A Golden Opportunity for Small Diversified Farmers. Herb Society of America, Annual Meeting Tarrytown, NY, June 1, 2018. Poster presentation.
- Type:
Other
Status:
Other
Year Published:
2018
Citation:
Skinner, M. B.L. Parker & A. Ghalehgolabbehbahani. 2018. Saffron production: Life Cycle of Saffron (Crocus sativus). The North American Center for Saffron Research & Development. Univ. of Vermont, Burlington, VT USA. Fact sheet
- Type:
Other
Status:
Other
Year Published:
2017
Citation:
Skinner, M. B.L. Parker & A. Ghalehgolabbehbahani. 2017. Where to buy corms. The North American Center for Saffron Research & Development. Univ. of Vermont, Burlington, VT USA. Fact Sheet
- Type:
Other
Status:
Other
Year Published:
2018
Citation:
Skinner, M. B.L. Parker, C.F. Sullivan, L. Sisco & A. Ghalehgolabbehbahani. 2018. Survey of Needs and Priorities for Saffron Research and Development. The North American Center for Saffron Research & Development. Univ. of Vermont, Burlington, VT USA. https://www.uvm.edu/~saffron/Resources/Factsheets/Saffron%20Needs%20Survey%202018.pdf
- Type:
Other
Status:
Other
Year Published:
2018
Citation:
Davari, A. & BM. Skinner. 2018. Cooking with Saffron. The North American Center for Saffron Research & Development. Univ. of Vermont, Burlington, VT USA.
- Type:
Other
Status:
Published
Year Published:
2018
Citation:
Skinner, M. B.L. Parker & A. Ghalehgolabbehbahani. 2018. Summer Sampling of your Saffron Bed for Corm Survival. The North American Center for Saffron Research & Development. Univ. of Vermont, Burlington, VT USA. Fact sheet
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2018
Citation:
Ghalehgolabbehbahani, A. 2018. Saffron Biology and Production in Cold Climates. Saffron: From Production to Processing. 16 March 2018, Burlington, VT USA Presentation
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2018
Citation:
Davari, A. 2018. The Culture of Saffron. Saffron: From Production to Processing. Saffron workshop, 16 March 2018, Burlington, VT USA Presentation
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2018
Citation:
Skinner, M. & B.L. Parker. 2018. How does your saffron grow? Round Table Discussion. Saffron: From Production to Processing. 16 March 2018, Burlington, VT USA Presentation
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2018
Citation:
Ghalehgolabbehbahani, A. & H. Rotteveel. 2018. Drying and Storing Saffron. Saffron: From Production to Processing. 16 March 2018, Burlington, VT USA Presentation
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2018
Citation:
Davari, A. & K. Mirza. 2018. Saffron Extraction and How to Use It. Saffron: From Production to Processing. Saffron workshop, 16 March 2018, Burlington, VT USA Presentation
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