Final report for SW21-923
Project Information
Local strawberries are in high demand throughout the Intermountain West, but outdoor production to meet demand is risky due to late frosts which threaten yields. Previous research at Utah State University (USU) has shown that high tunnel strawberry production could potentially meet consumer demand and be highly profitable when compared to outdoor or low tunnel production. Despite grower interest, adoption of high tunnel strawberry production in the West is low due to uncertainties over cultivar performance and best management practices for soil fertility and diseases using organic methods. High tunnel growing conditions can promote grey mold (Botrytis cinerea) and powdery mildew (Podosphaera aphanis) epidemics, requiring weekly fungicide application, a practice that is not sustainable for small scale growers using organic or natural growing methods.
Compost is a cost-effective organic fertilizer with potential for enhancing disease suppression but yield response can vary due to challenges associated with predicting nutrient release and plant uptake, which often translates to growers over applying or eschewing the use of compost altogether. Indeed, our preliminary research has shown considerable variability in growth and nitrogen (N) uptake among strawberry cultivars when grown on slow-release organic sources of N like composts. Compost-mediated resistance can also be complemented through use of microbial biological control agents (mBCAs), which can be directly applied by growers or transferred to flowers by pollinators such as bumblebees. While strawberries are self-pollinating, pollinators and their foraging activity can have synergistic effects on grower outcomes through increasing berry size and yields, and by vectoring mBCAs.
This project will improve management options for sustainable strawberry production by harnessing synergies between season extension, cultivar identity, nutrient uptake on compost, and disease suppression by addressing the following objectives: 1) assess strawberry cultivars for nutrient uptake and growth on less readily available organic nutrient sources, 2) assess how mBCA effectiveness, both singly and in mixtures, varies with strawberry cultivar and compost use 3) evaluate use of bumblebee pollinators to enhance biological control and yield 4) assess market value and consumer preference for local strawberries, 5) improve grower and student understanding of high tunnel strawberry production through on-farm trials field days, training events, the development of new online resources and course material. The most promising cultivar/management combinations will be tested and showcased on five commercial farms, with results published in factsheets and videos. This research is unique in that it explores innovative and sustainable ways to solve common production problems. Recent data published by the National Agriculture Statistics Service shows strawberries are among the top selling organic crops. With improved management options, local farms could meet consumer demand, bolster local economies, and improve environmental impacts. The information generated will help growers to potentially transform their production systems, reduce or eliminate reliance on toxic chemicals, improve nutrient management and soil health, and meet market demand for local, sustainably produced strawberries.
The long-term goal of this project is to increase the production of strawberries for local markets, improve soil nutrient and disease management, and reduce reliance on purchased inputs through addressing the following specific, short-term objectives: 1) assess cultivars for nutrient uptake and growth on less readily available organic nutrient sources such as compost, 2) assess how mBCA effectiveness, both singly and in mixtures, varies with strawberry cultivar and compost use 3) explore the use of bee pollinators to enhance biological control and yield and 4) assess market value and customer preferences for local strawberries grown under various production schemes and 5) Improve grower and student understanding of high tunnel strawberry production through on-farm trials, field days, training events, the development of new online resources and course material. Initial selection of cultivars and mBCAs occurred in the greenhouse and laboratory in year one, with a subset field tested at the USU Student Organic Farm in years one through three. The most promising cultivar and management combinations will be tested and demonstrated on five commercial farms in years two and three. Five commercial growers and one student farm manager will advise the project through twice yearly meetings throughout. Results will be showcased in Utah and five neighboring states through on-farm tours and workshops, and published in factsheets, videos, and peer-reviewed publications
If funded, we will begin screening cultivars in the greenhouse in April 2021 in time for plug plant production in July 2021. The first trials will be planted in early September 2021 and harvested in the spring of 2022. The second trials will commence in early April 2022 for harvest in the late summer and fall of 2022. A second round of trials will commence on the same schedule but starting in the fall of 2022 and spring of 2023.
Amino acid uptake measurements and mBCA leaf bioassays will commence in the fall of 2021 and will be completed within a year. Bumblebee trials will commence in the spring and late summer of 2022 to coincide with blossom and fruit set. A second round of bumblebee trials will commence in the spring and late summer of 2023. Economic field experiments will take place in 2022.
Grower advisory meetings will be held in October and March of each year. A high tunnel construction workshop will be held on the USU Student Organic Farm in August 2021. Five additional high tunnel construction and strawberry management workshops will be held in neighboring states in years two and three. Field days will be held in April or May in years two and three of the project. Post-program evaluations will be conducted on site or online directly after all field days, workshops etc. Follow-up surveys to asses producer adoption will be conducted one and two years after each program.
Data on yields, input costs and revenue will be collected from grower participants during each spring or fall planted trial. Data will be used to update an existing peer reviewed strawberry production budgets in the final year of the project. Outreach and journal articles will also be finalized in the final year of the project.Gantt chart
Cooperators
- - Producer
- - Technical Advisor - Producer (Educator)
- - Technical Advisor - Producer
- - Technical Advisor - Producer
- - Technical Advisor - Producer
- - Producer
- - Producer
- - Producer
- - Technical Advisor - Producer (Educator and Researcher)
- - Technical Advisor - Producer (Educator)
- - Producer
- - Producer
- - Producer
Research
We hypothesize that there is a positive relationship between growth and amino acid uptake on compost in the greenhouse and growth and productivity on compost in the field.
We hypothesize that more diverse mBCA treatments will be more effective at preventing disease than those that are less diverse and that strawberry plants grown on compost will be most responsive to mBCA treatment.
We hypothesize that use of bumble bees in high tunnels will have synergistic effects on strawberry health and yield quality.
Objective 1) Assess strawberry cultivars for nutrient uptake and growth on less readily available organic nutrient sources such as composts.
(i) Rationale and Hypotheses. We built on preliminary data already collected that suggests strawberry cultivars show considerable variability in growth on slow-release organic sources of N like compost (Reeve et al. 2017) and take up organic molecules such as amino acids directly (Reeve et al. 2008). We used greenhouse trials to select strawberries with extreme differences in growth on compost and confirm these results in high tunnels. We hypothesized that there is a positive relationship between growth and amino acid uptake on compost in the greenhouse and growth and productivity on compost in the field.
(ii) Approach. Nineteen commercial cultivars were obtained from nurseries (e.g. Nourse Farms, Whately, MA). Eleven cultivars were propagated according to Rowley (2010) and planted in high tunnels at the USU Student Organic Farm in the fall of 2023. Ten cultivars were planted directly in high tunnels at the USU Student Organic farm in the spring of 2023 and harvested in the spring and fall of that year.
Fall and spring plantings of strawberries grown with compost (Millers Inc, Hyrum UT) with and without soluble N fertilizer (fish emulsion on organic farms) were established on the USU Student Organic Farm in Sept 2023 and March 2024. Steer manure compost was applied prior to planting at a rate of 120 lb total N per acre, assuming 25% N availability. One 70 x 14ft tunnel was dedicated to fall and one to spring production at the student farm. Eleven compost/cultivar treatment combinations (3ft. of bed per treatment with 6 plants per plot) with three replicate plots were established per high tunnel. Best performers selected in greenhouse trials as well as Chandler and Seascape that are expected to be poor were included to test the relationship between growth on compost and performance in the field. Plant survival, number of crowns, runners and leaf chlorophyl were recorded. Total and marketable berry yield, fruit size, plant growth, leaf chlorophyll, leaf N content and disease incidence were measured. Soil health indicators (organic matter, microbial biomass, available soil nutrients, pH and EC) were assessed at two points during the growing cycle according to Gavlak (2003) and Anderson and Domsch (1978). Data from fall and spring plantings was analyzed separately using a random complete block design with two factors (cultivar and compost) with harvest time as repeated measure. Common cultivars were compared across years and used to assess yield stability over time. Unique cultivars present in any given year only were compared by year.
Amino acid uptake was measured on four cultivars according to Reeve et al. (2008). Briefly, C14 labelled glycine were added to soil containing a rooted strawberry plant. The surface of the soil was sealed with wax to prevent atmospheric uptake and the plants placed in a vented manifold system. Glycine, nitrate, and ammonium uptake were determined after 24 hours. The presence of intact labelled amino acids in the plant tissue was confirmed by HPLC analysis.
Objective 2) Assess how mBCA effectiveness, both singly and in mixtures, varies with strawberry cultivar and compost use.
(i) Rationale and Hypotheses. Application of mBCAs represents a sustainable alternative for disease control. To date, a handful of mBCAs have been screened for use in limiting powdery mildew (Podosphaera aphanis) and grey mold (Botrytis cinerea) development in strawberry (Sylla et al. 2013). Though single and paired species mBCA treatments demonstrate promise, they remain subpar to fungicides (Pertot et al. 2008; Silla et al. 2013). Increasingly, it is recognized that a positive relationship exists between microbial community diversity and resistance to pathogen invasion (Santhanam et al. 2015). Thus, we hypothesize that more diverse mBCA treatments will be more effective at preventing disease than those that are less diverse and that strawberry plants grown on compost will be most responsive to mBCA treatment.
(ii) Approach. mBCA (single, Aureobasidium pullulans) effectiveness against grey mold (Botrytis cinerea) was evaluated across cultivars. The focus on A. pullulans was dictated by commercial availability of the mBCA for producers, as well as prior work showing its effectiveness against pathogens, including strawberry (Sylla et al. 2013; Iqbal et al. 2022). We also focused on grey mold, as powdery mildew has been less of a concern in our trials, and we wish to ensure post-harvest health of our berries for market. To test efficacy, we performed a detached strawberry leaf disk bioassay, following Sylla et al. (2013). Briefly, leaf disks [1 cm diameter, N = 30 per treatment (mBCA or control) per cultivar] were sourced from leaves of strawberry mother plants grown in the greenhouse for plug plant production. The control treatment consisted of leaf disks dipped in sterile Ringer solution, while the mBCA-treated disks were treated at a density of ~1 x 107 CFU/mL. Treated disks were incubated at 25°C (65% RH), with an alternating 12 hr. light/dark photoperiod. After 24 hr, leaf disks were challenged with B. cinerea conidia and incubated to allow for pathogen development. Leaf disks were processed to determine levels of conidia production, using microscopy and a Thoma counting chamber to determine the number of conidia per cm2 of leaf. These data will extend our previous dataset on cultivar-dependent performance of Aureobasidium, which has been performed with each round of cultivars purchased in spring for evaluation. A complementary assay was performed with leaf material stemming from the planted trials of cultivars grown on and off compost, to determine how Aureobasidium and compost-addition interacts to affect mold resistance.
Objective 3) Evaluate use of bee pollinators to enhance biological control and yield.
(i) Rationale and Hypotheses. Cross-pollination can significantly enhance strawberry yields, fruit quality, shelf-life, and commercial value (Klatt et al. 2014; Wietzke et al. 2018; MacInnis and Forrest 2019). Moreover, pollinators (e.g., bumble bees) naturally disperse microbes among flowers and can vector with considerable success (Yu and Sutton 1997; Kapongo et al. 2008; Russell et al. 2019). We hypothesize that use of bumble bees in high tunnels will have synergistic effects on strawberry health and yield quality.
(ii) Approach. Assessment of bee effectiveness for biocontrol, yield enhancement, and how this varies with soil background, was tested through cage trials, performed in a tunnel at the USU Student Organic Farm. Commercial bumble bee colonies (Bombus impatiens, Biobest Group) were obtained and fitted with an mBCA inoculum dispenser, following Yu and Sutton 1997; Al-mazra’awi (2004). Each cage (i.e., treatment) contained 18 strawberry plants. The RCBD experiment was replicated 4 times. Treatments consisted of control treatment with neither inoculum nor bees, mBCA inoculum sprayed alone, bees alone, and mBCA inoculum + bees. Three cultivars (AC Valley, Chandler, Galetta) were selected for this experiment and half of the plants were treated with either control or compost-amended soil as in Obj. 1.
After establishing caged arrays, we introduced the colonies to allow for bee foraging and dispersal of mBCA inoculum. Following a three-day period of bee activity, flowers and leaves of eight randomly selected plants per soil treatment were artificially inoculated with mold conidia. After six days, leaf and flower samples were harvested for disease assessment, with mBCA dispenser removed from colonies. After each tissue-sampling, remaining inoculum was dried and weighed to determine the amount delivered. Finally, we assessed fruit yield and quality by measuring fruit production, mass, shape (length:diameter ratio), soluble solids, titratable acidity and total phenolic compounds.
Objective 4) Assess market value and consumer preference for local strawberries.
A graduate student worked with growers to collect information to revise and update previously published cost of production budgets (Maughan et al., 2014). Pricing estimates ere based on current local pricing of strawberry cultivars produced collected from the USU farmers’ market and dining outlets (e.g., Luke’s Café), the Cache Valley Gardeners Market, Ogden and Salt Lake City farmers markets and also through interviews with local chefs and retail outlets. Cost estimates were based on inputs used during study trials and those provided by local vendors. Cost of production budgets were used to educate growers on production and marketing methods at Extension field days, workshops, webinars, and online. These budgets provide growers with good estimates of the potential profitability (by cultivar and production methods) of strawberries under reduced chemical and organic production systems, thus enabling growers to better assess and adopt study recommendations.
Consumer preferences and willingness to pay for successful strawberry cultivars and production systems was evaluated through economic field experiments conducted with Northern Utah residents. Experiments include blind sensory analysis of strawberry cultivars followed by a survey including choice sets to determine consumer preferences and willingness-to-pay (WTP) based on strawberry product pricing, strawberry sensory and production attributes, as well as consumer psychographics and demographics (Barnes et al. 2014; Bosworth et al. 2015; Drugova et al. 2020). Field experiments were conducted at farmers’ markets (Logan, Ogden, and Salt Lake City), the USU campus, and local retail outlets. Market viability studies such as these are an important part of understanding consumer interest in new products/production methods such that product pricing, attributes, sales venues, and promotional messages are appropriate for the target market(s), which are also identified through this analysis. A study on consumer interest and WTP for eco-friendly and organic peaches found that reduced chemical and eco-friendly production methods are valued by consumers in Northern Utah (Curtis et al., 2020).
Objective 1) Assess strawberry cultivars for nutrient uptake and growth on less readily available organic nutrient sources such as composts.
Overall, crop yields of the June bearing strawberries in 2024 were low, likely due to early season blossom loss to freezing. Compost applied at planting was sufficient for June bearing strawberries. There was no significant effect of additional fertilizer either in the form of fish emulsion or feathermeal. In fact, there was a negative effect of added fertilizer on winter survival of some cultivars e.g. Flavorfest, Cabot, Cavendish and Archer suggesting that additional fertilizer negatively affected dormancy in some cultivars. Crown count and chlorophyll content measured in the fall prior to dormancy were most predictive of crop yield. Sparkle, Galetta, Cavendish, D’light, Dickens, AC Valley and Jewel were the top ranked June bearing cultivars across years.
Yields from the spring planted day neutral cultivars in 2024 were quite good, ranging from 350 – 425 g per plant and similar to yields for the 2022 and 2021 growing seasons. Cultivar ranking was Portola, Cabrillo, Monterey, Albion, Royal Royce Seascape and Charlotte. These same cultivars were among the top performing cultivars in previous years also, although the individual placement varied by year. As in previous years, there was no significant response to additional fertilizer applications, suggesting that pre-season compost when applied at recommended nitrogen rates and assuming a 25% total N availability was sufficient to meet the nutrient requirements of day neutral as well as June bearing strawberries. Annual additions of compost would likely need to be reduced to avoid over application of phosphorus and other salts. Soil tests on commercial high tunnels showed high soil fertility so all on-farm trials were planted without pre-plant compost applications.
Amino acid uptake was greatest in the coastal strawberry (Fragaria chiloensis), a similar finding to that reported by Reeve et al. 2008. There was also a threefold difference in amino acid uptake between Charlotte and Chandler (Fig 1) which correlated with their performance in the field. Greenhouse trials also showed that strawberries grew best on the complete nutrient solution but that there was considerable variability among commercial cultivars in their ability to grow on compost alone. There was no clear relationship between growth on compost in the greenhouse and amino acid uptake, however. This suggests a complex relationship between the ability of strawberries to grow on compost, organic nitrogen uptake and performance in the field. In fact, the tolerance of strawberry cultivars to high soil pH and their susceptibility to iron chlorosis appears to be the major driver of field productivity in our systems.
Fig. 1. Amino acid uptake by three domesticated strawberry cultivars compared to a wild strawberry species.
Objective 2) Assess how mBCA effectiveness, both singly and in mixtures, varies with strawberry cultivar and compost use.
Since the start of the project, 28 strawberry cultivars have been evaluated for their basal resistance to grey mold (Botrytis cinerea), as well as their response to Aureobasidium treatment and associated resistance against the disease. Among cultivars evaluated, D’light, Earliglow, Jewel, and Sparkle displayed the lowest levels of resistance against the pathogen, while Daraselect, Festival, Galetta, Keepsake, Seascape, and Stella had comparatively high levels of resistance. Treatment with Aureobasidium as an mBCA significantly limited B. cinerea growth across nearly all cultivars; however, its efficacy varied with cultivar background (p < 0.001). For a subset of cultivars, we also compared basal resistance and mBCA performance when plants were grown on and off compost, finding a negligible effect of the soil amendments.
To determine the mechanism of resistance and why this variability might exist, we also sampled tissues to measure beta-glucanase and chitinase activity, as previous work has shown that expression of these two defense-related enzymes may be enhanced following treatment with this mBCA. Analyses to date largely corroborate this pattern, revealing that Aureobasidium application does enhance expression of the genes responsible for these enzymatic products, but expression varies with cultivar background in ways that mirror results from our leaf disk assay. Cultivar resistance data to grey mold and the efficacy of Aureobasidium for treatment will be communicated to relevant stakeholders through both a USU Extension Fact Sheet and peer-reviewed publication. Both are currently in preparation, with anticipated submission early this summer.
Beyond disease, pests such as spider mites and aphids proved to be more of a challenge for our high tunnel strawberry plantings. Given these observations (also observed by our producer-collaborators in their plantings), we also took data on spider mite and aphid occurrence/densities across cultivars planted out at the USU Student Organic Farm. These data on pest preferences and cultivar resistance, along with recommendations for management under organic growing conditions, will be communicated to stakeholders in a companion USU Extension Fact Sheet to be developed spring and summer 2025. Mite specific data, including coupled assays on mite performance, will also be communicated in a future peer-reviewed publication.
Objective 3) Evaluate use of bee pollinators to enhance biological control and yield.
Bumblebee pollination
Akin to above, the fall 2022 planting at the USU Student Organic Farm for the first iteration of pollination trials was largely unsuccessful. Herbivory (voles) and winter kill substantially reduced samples sizes available for work. Moreover, vole tunneling made maintenance of pollination treatments challenging, as bumblebees deployed for the work could easily make their way to neighboring cages with relative ease under the plastic mulch covering. As a result, yields were very low and it was difficult to evaluate whether there was a positive effect of pollinators on production outcomes. Among the three cultivars screened however, Galetta performance was most consistent and is likely a good choice for producers given other management considerations.
As noted, this experiment was repeated in 2023-2024 given the challenges experienced the previous year. While winter survival significantly improved following addition of hay cover and an additional row cover, plants still suffered from low yields due to frost damage inflicted to flowers, making it a challenge again to evaluate the effect bumblebee pollinators had on production outcomes. Corroborating previous work, we found that bumblebees can effectively disperse the mBCA to flowers as they forage in the tunnels, with no difference observed among cultivars (AC Valley, Chandler, Galetta) in inoculum delivery. Galetta also continued to be the best performing/most consistent cultivar.
Solitary bee pollination
Given some of the challenges experienced working with bumblebees in the high tunnel environment, including the fact that a native Intermountain US species isn’t commercially available for purchase and use by producers, we’ve worked to evaluate alternative bee pollinators for effective berry pollination. Mason bees of the genus Osmia in particular are solitary cavity-nesting bees that have garnered increasing interest as alternative pollinators for berry pollination, given their propensity to nest in man-made structures, noted effective pollination of other crops, and low dispersal rates from sites of introduction. Despite this, barriers to wider adoption remain, including their inclinations toward specialization or generalization to other available floral resources in an agricultural landscape, along with concerns about potential performance in a closed agricultural environment.
More specifically, between 2023-2024, we tested the aptitude and fidelity of 3 Osmia species (Osmia lignaria, O. bruneri, and O. ribifloris) as pollinators of blueberries, strawberries, and currants. Pollen samples were collected at a selection of berry field sites (four blueberry, three strawberry, six raspberry, and one currant) in Corvallis, Oregon, and Paradise, Utah. Nesting rates and pollen provision samples from Osmia nests were analyzed. Samples were identified to determine visitation to the target crop, indicating pollination potential. To date, we’ve found
that Osmia lignaria pollinates strawberries in open-ended high tunnels and O. ribifloris seemingly collects pollen exclusively among blueberries. Interestingly, we observed the late summer bee, O. bruneri, collecting pollen on an early spring berry: currants. Bee nesting rates, however, were low for the three species. This may be due to mismatches in crop bloom with their natural phenology. Ongoing research will continue to investigate overwintering strategies that could optimize the timing of each species with their target crop.
Objective 4) Assess market value and consumer preference for local strawberries.
Due to the lack of project fruit available due to weather, pest, and other issues, Utah consumer preferences and willingness to pay for conventional, organic, locally grown, and GMO-free strawberries was assessed through an online survey administered through Qualtrics in the fall of 2023. A total of 384 responses were collected and analyzed. Initial results show that Utah consumers are willing to pay similar premiums for local and organic strawberries, but even higher premiums for strawberries with both labels (see Table 1). Organic was ranked ninth out of 18 attributes consumer respondents considered when purchasing fruit, locally grown ranked seven. Strawberries were ranked second (with bananas and after apples) in the fruits consumers consumed at least monthly, indicating strong preferences for strawberries. While respondents indicated they would pay more for local and organic products, they had little familiarity with specialized labeling programs and production methods. They agreed that locally grown products are fresher and purchasing supports local growers, and that organic products are healthier and safer, but are too expensive.
Seven Extension factsheets have been published with one currently under peer review. One Ph.D. student is writing a dissertation based upon this research and three academic papers will result.
Table 1: Respondent WTP ($USD) by Label and Label Combinations
Economic experiments with purchased fruit were conducted in the summer of 2024. Lab experiments included blind sensory analysis of specialty labelled (organic, local, etc.) strawberries followed by a survey including choice sets to determine consumer preferences and willingness-to-pay (WTP) based on strawberry product pricing, sensory and production attributes, as well as consumer psychographics and demographics. A total of 116 consumers completed the experiment.
Pricing results are provided in Table 2. Results show that consumers were willing to pay the most on average for certified organic strawberries, followed by locally-grown strawberries. This mirrors the overall taste ratings for the berry samples (See Table 3 below). Intriguingly, though the “locally-grown” and “product origin unknown” strawberries came from the same farm on the same day, the strawberries that were labeled as being locally grown were valued $1.31 more than their unlabeled counterparts on average. The “product origin unknown” berries were valued the least.
Though the difference was not as wide a similar gap was observed for “certified organic” and “production type unknown,” with certified organic strawberries being valued $0.69 more on average despite the berries being produced the same way and purchased from the same store on the same day. The differences in price between the labeled and unlabeled strawberries demonstrate the higher value consumers place on attributes described in the labels and the influence that labels have on consumers’ perceptions. For every strawberry product, the “no information” group was willing to pay more for a one-pound package than the “yes information” group. Those that were more informed about fruit production methods prior to participating in the test may be willing to spend more on fruit products.
Table 2: Strawberry Bids ($/pound)
Table 3: Strawberry Taste Ratings (Scale of 1-7)
Due to various production issues (weather, pests, etc.) impacting trial yields, the financial feasibility of organic strawberry production was not possible. Strawberry production enterprise budgets, in which growers can enter their yield information to analyze the potential profitability of organic production on their farm will be provided to interested growers.
Two outreach presentations and one academic presentation were made on survey results in 2024. Seven Extension fact sheets were published, one Ph.D. dissertation chapter was written and has been submitted for journal review. A second academic paper will be written and submitted in 2025. In the summer of 2024, consumer taste studies were conducted in Utah. Two Extension fact sheets based on study results were drafted in 2024 and were submitted for review in early 2025. An academic paper will be drafted and submitted in 2025 on these results as well.
The extension fact sheets published in 2024 (7) have 192 total downloads (USU digital commons only) so far. A webpage for all publications, including Extension and outreach materials for this project can be found at: https://extension.usu.edu/apec/agribusiness-food/fresh-produce-sales-direct-pricing. This website had 209 views in 2024.
Research Outcomes
We are still in the process of synthesizing our data in order to provide recommendations to growers. Our assessment to date suggests that cultivars need to be selected carefully for adaptation to both cold and hot conditions, and for tolerance to high soil pH. Galletta, a June bearing cultivar developed in North Carolina appears to meet these diverse needs well. Compost applied at a rate of 120lb total N per acre was found to be sufficient for strawberry production with no trials or cultivars responding to additional side dress nitrogen. In fact, our on-farm trials made clear that pests such as spider mites, wood lice and ants are more problematic than soil fertility or disease issues under organic management systems and future research is needed in this area.
A graduate student on the project also published a review/perspective piece on the promise for managing the floral microbiome as a sustainable disease management option.
Burgess, E. C., & Schaeffer, R. N. (2022). The floral microbiome and its management in agroecosystems: a perspective. Journal of Agricultural and Food Chemistry, 70(32), 9819-9825.
Education and Outreach
Participation Summary:
Outreach
The USU Student Organic Farm was the only participating farm in trials this year as we were operating under the budget constraints of a no-cost extension that was granted to make up for failed trials in the 2023 growing season. A field day was held at the student farm in August which featured the strawberry research project and also included an opportunity for the participants to sample the different strawberries.
Presentations to grower and industry audiences
We organized two half-day workshops on high tunnel management in 2024. One in the Southwest part of the state (held in Iron County), and one in the northeast corner (Uintah County). The workshops featured a full program of topics related to high tunnels, including soil management, fertility, temperature management, and cropping options (fruit, vegetables and cut flowers). Both of these workshops had enrollment caps based on the space available to hold the meetings. Both of them maxed out their enrollment caps (and in one case exceeded it slightly)
Following are the presentations made at each of those workshops. The “fruit options” talks focused heavily on the results from this research, but also talked briefly about raspberry and blackberry systems
Summary of Outreach activities/presentations.
Project Outputs
Educational Opportunities
- One Extension intern, undergraduate
- One MS student gained experience in high tunnel organic strawberry management, research design, data collection and analysis, writing and presenting.
- One MS student gained experience in pollinator selection and management for high tunnel berry crops, including research design, data collection and analysis, writing and presenting.
- One undergraduate research assistant experience in high tunnel organic strawberry management, research design, and data collection.
- Six undergraduate student farm interns gained experience in high tunnel organic strawberry management, research design and data collection.
Key Areas Taught
- Strawberry disease management in controlled environments (e.g., high tunnels) was showcased to USU students through lectures, site visits to the USU Student Organic Farm, and laboratory exercises performed in the cross-listed undergraduate and graduate course Introduction to Plant Pathology, taught by co-PI Schaeffer each fall. This course typically has an enrollment of ~48 students each semester.
Outreach Presentations
- Black, B. “High Tunnel Design Considerations and Site Selection”, and “High Tunnel Berry Basics.” Eastern Idaho High Tunnel Workshop, Caldwell, Idaho, 6 April 2023 (21 in person).
- Curtis, K., M. Pignatari, and M. Langford. “Consumer Preferences for Utah Fruit Products.” Presented at the 2024 Utah State Horticultural Association Annual Meeting, Spanish Fork, UT, January 26. 75 attendees.
- Black, B. “High Tunnel Design and Management: Common mistakes of first-time high tunnel farmers and how to avoid them.” Harvest and Hearth Conference. Ada Soil and Water Conservation District. Boise, Idaho, 9 Feb 2024 (40 participants).
- Black B. “Selecting Crops for Your High Tunnel.” Harvest and Hearth Conference. Ada Soil and Water Conservation District. Boise, Idaho, 9 Feb 2024 (46 participants).
- Curtis, K., M. Pignatari, and M. Langford. “Utah Consumer Preferences for Local and Organic Fruit.” Presented at the 2024 Utah Urban and Small Farms Conference, Online, February 21. 82 attendees.
- Black, B. “High tunnel Management: Temperature, Water and Soil.” Southern Utah High Tunnel Workshop, Cedar City, UT, 16 Mar 2024 (47 participants).
- Black, B. “High tunnel cropping options: Fruit.” Southern Utah High Tunnel Workshop, Cedar City, UT, 16 Mar 2024 (47 participant).
- Black, B. “High tunnel cropping options: Fruit.” Uintah Basin High Tunnel Workshop, Vernal, UT 12, Oct 24 (28 participants).
- Black, B. “High tunnel Management: Temperature, Water and Soil.” Uintah Basin High Tunnel Workshop, Vernal, UT, 12 Oct 24 (28 participants).
Outreach Publications (Under Review)
- Langford, M., and K. Curtis. “Fruit Consumption Indicators: Who Consumes More Fruit in Utah?” Draft USU Extension Fact Sheet.
Outreach Publications (Published)
- Langford, M., K. Curtis, and M. Pignatari (2024). “Consumer Perceptions and Preferences for Utah Fresh and Packaged Fruit.” USU Extension Fact Sheet, Applied Economics/2024-04pr.
- Langford, M., K. Curtis, and M. Pignatari (2024). “Utah Consumer Preferences and Willingness to Pay for Specialty Labeled Fruit Products.” USU Extension Fact Sheet, Applied Economics/2024-05pr.
- Langford, M., and K. Curtis (2024). “Fruit Consumption Indicators: Who Consumes More Fruit in Utah?” USU Extension Fact Sheet, Applied Economics/2024-01pr.
- Langford, M., and K. Curtis (2024). “Fruit Production and Opportunities for Growers in Utah.” USU Extension Fact Sheet, Applied Economics/2024-02pr.
- Langford, M., and K. Curtis (2024). “Utah Fruit Grower Assessment Results.” USU Extension Fact Sheet, Applied Economics/2024-03pr.
- Curtis, K., M. Langford, and T. King (2024). “Target Consumers for Locally Grown Fruit in Utah.” USU Extension Fact Sheet, Applied Economics/2024-09pr.
- Curtis, K., M. Langford, and T. King (2024). “Target Consumers for Organically Grown Fruit in Utah.” USU Extension Fact Sheet, Applied Economics/2024-10pr.
Outreach Publications – Drafted
- Langford, M., and K. Curtis. “Consumer Preferences for Specialty Labeled Strawberries. USU Extension Fact Sheet.
- Langford, M., and K. Curtis. “Intermountain Consumer Attitudes toward Locally Grown Strawberries. USU Extension Fact Sheet.
- Jones, M., K.K. Graham, R.N. Schaeffer and B.L. Black. Pollinator Management for High Tunnels. USU Extension Fact Sheet.
- Organic Fertility Management for Small Acreage Farms (this arose directly from feedback we received at the Iron County workshop)
- Iron Chlorosis in Strawberries.
- Irrigation Management for High Tunnel Strawberry Production (also arose from workshop participants
Academic Publications
Burgess, E. C., & Schaeffer, R. N. (2022). The floral microbiome and its management in agroecosystems: a perspective. Journal of Agricultural and Food Chemistry, 70(32), 9819-9825.
Five academic papers will result from the strawberry lab experiments and Mark’s thesis on cultivar selection and nutrient management in organic high tunnel strawberries.
Five additional academic papers will stem from Emily Burgess’ and Miranda Jones’ research on strawberry disease and pest management, as well as on berry pollination using bumblebees and solitary bees. We anticipate submitting one this summer on cultivar-dependent resistance to grey mold and the efficacy of Aureobasidium for biological control. The others are on track for fall 2025 submission.
Academic Presentations
- Kindred, M., R. Reeve, B. Black, R. Schaeffer. Early season nitrogen availability in high tunnel strawberries. ASA, CSSA & SSSA Annual Meeting, Oct 29th – Nov 1st 2023. St. Louis, MO. Poster.
- Pignatari, M., and K. Curtis. “Consumer Preferences for Fresh and Processed Fruit Products: An Economic Experiment.” Selected paper to be presented at the Western Agricultural Economics Association Annual Meeting, San Francisco, CA, June 2024.
- Kindred, M., R. Reeve, B. Black, R. Schaeffer. Nitrogen Utilization from Compost in Organic Strawberries. ASHA Annual Meeting, Sep 23rd – 27th 2024. Honolulu, HI. Poster.
- De LaTorre, E. K. Paule, M. Kindred, R. Reeve, B. Black, R. Schaeffer. Strawberry response to compost versus inorganic nitrogen. ASHA Annual Meeting, Sep 23rd – 27th 2024. Honolulu, HI. Poster.
- Vaughan, H, Z. Smutko, E. Burgess, S. Jadhav, M. Borghi, M. Kindred, J. Reeve, R. Schaeffer. Is microbe-assisted resistance to grey mold in strawberry cultivar-dependent? Northeaster Natural History Conference, Albany, NH, April 2024.
- Jones, M, KK Graham, and RN Schaeffer. 2025. Annual Meeting of the Entomological Society of America – Pacific Branch (Salt Lake City, UT). To berry or not to berry: Recognizing mason bees as loyal berry pollinators using pollen ID. Poster Presentation.
- Jones, M, KK Graham, and RN Schaeffer. 2024. Annual Meeting of the Entomological Society of America (Phoenix, AZ). Evaluating 3 species of mason bees for berry crop pollination. M Jones, KK Graham, and RN Schaeffer. Oral Presentation.
- Jones, M, KK Graham, and RN Schaeffer. 2024. Annual Meeting of the Entomological Society of America – Pacific Branch (Waikoloa Beach, Hawaii). Investigating the aptitude of 4 mason bee species for pollination of berry crops in varied agricultural settings. M Jones, KK Graham, and RN Schaeffer. Oral Presentation.
Education and Outreach Outcomes
There continues to be a strong interest in high tunnel management and production of berries and other crops in Utah and the surrounding states. Many of our workshops were filled to capacity. Continuing education and outreach in high tunnel production will be important to meet the growing needs of the future.
- Strawberry disease management in controlled environments (e.g., high tunnels) was showcased to USU students through lectures, site visits to the USU Student Organic Farm, and laboratory exercises performed in the cross-listed undergraduate and graduate course Introduction to Plant Pathology, taught by co-PI Schaeffer each fall. This course typically has an enrollment of ~48 students each semester.
Improved understanding of high tunnel temperature management
Improved understanding of the importance of cultivar selection when growing strawberries
Improved understanding of organic fertility and soil health management strategies