Final report for FW23-418
Project Information
Crop losses due to certain key pests like cucumber beetles, aphids, thrips, lepidoptera larvae, fusarium and more have been persistent problems in the organic cut flower industry. Currently, there is a minimal amount of readily available and regionally-specific information regarding sustainable Integrated Pest Management (IPM) practices for organic cut flower farms that are effective and economical. The question our research project is answering is what IPM methods are cost-effective for reducing losses due to key pests. This project is utilizing monitoring, data collection, and analysis; followed by implementation, further monitoring and data collection, and additional refinement as needed.
During the monitoring phase, we identified key pests. During analysis, after identifying the highest pressure pests, establishing economic thresholds, and analyzing what the best sustainable management methods are, we implemented those methods, and continued to monitor and record pest pressure and efficacy of the implementation utilized.
The significance of this project was the development of research material on central coast pests on an organic cut flower farm that were and continue to be shared with the broader community, as well as decreasing pest pressure at Do Right Flower Farm. We have disseminated existing research, tools and techniques for monitoring, project results, and IPM methodologies to the wider agricultural community through social media postings, the ASCFG newsletter, two bilingual field days, and two off-site educational events, and a virtual final presentation that is recorded and available on youtube. This final research report should help inform other growers in the region on successful methods to control key pests, ideally giving other producers better information and methods to improve yields and profits across all central coast organic flower productions.
Research:
- Identify key pests affecting a Central Coast CA organic cut flower farm.
- Research and determine cost-effective sustainable IPM methods for suppressing key pests.
- Reduce losses from key pests.
Education:
- Share research findings (research data, economic impact, implementation strategies) with local Central Coast growers and farm educators in English and Spanish.
- Share tools and methods for monitoring so that they can be reproducible on other farms.
We've put together a GANTT chart for the project which should be viewable here: Timeline - Sheet1 (2)
Cooperators
- - Technical Advisor
Research
Do Right Flower Farm is a four-acre certified organic cut flower farm located approximately one mile inland from the central Pacific coast. The farm is oriented north-south on flat land between wooded hillsides recently burned in the CZU Complex fire of 2020. The farm is adjacent to Waddell Creek, just inland from Rancho Del Oso Nature and History Center, and includes plant communities including coastal strand, coastal scrub, riparian, meadow, marsh, Monterey pine forest, mixed evergreen forest, chaparral and redwood forest.
The climate of the farm is tempered due to its position in this valley and sees annual high temperatures of approximately 75 degrees in the summer months and annual lows in the high-40s in the winter months. The farm does not receive frost. Annual rainfall is approximately 14 inches, most of it accruing in February. The farm is located in Sunset Zone 17.
The farm is made up of a propagation greenhouse, four high tunnels and approximately 3.5 acres of open-field production. The farm produces certified organic cut flowers for florists and wholesale and retail markets.
The objective of our study was to determine proactive and cost effective integrated pest management (IPM) methods to reduce losses from key pests at Do Right Flower Farm.
Data on pest severity and crop volume was collected weekly using an established offline digital template in Google Sheets and all IPM methods used was documented as they were implemented.
The first year of the project included weekly monitoring and recording of pest severity and crop volume, including IPM methods implemented. After the first full season (April-October) of monitoring, pest severity was analyzed and additional IPM techniques and economic thresholds were identified to implement in the second year of the project.
The second year of the project included weekly monitoring of pest severity, crop volume and all IPM methods and economic thresholds implemented as a result of year one analysis. After the second full season (April-October) of monitoring, an analysis of the economic thresholds and IPM methods used has been conducted to determine the most effective IPM methods to reduce losses from key pests and maintain key pest pressure below thresholds.
The third year of the project included weekly monitoring of the pest severity and crop volume using the most effective IPM methods determined from year one and two to reduce losses from key pests and maintain thresholds.
Weekly monitoring of pest severity is being captured in a Google Sheet spreadsheet and analyzed using Pivot Tables and graphs. A mobile phone is being used to capture the data in the offline Google Sheet and capture photos.
The annual analyses was processed in Excel.
Materials used in the IPM methods are including various magnifying lenses, a phone-based camera, field knives, lab sample gathering tools (shovel, bags, markers, etc) and Google Sheets and Excel.
Comparison of IPM methods and resulting crop volume in years one, two, and three determined whether our objective has been achieved.
We measured and evaluated: IPM methods implemented, volume from weekly projections numbers, losses from pests reported using weekly projections report, and pest severity levels using the weekly scouting report.
Using regular and consistent crop monitoring to identify pest severity early and implement proactive IPM techniques allowed the grower to reduce losses from key pests and reduce costs from material applications and excessive labor. Establishing economic thresholds allowed the grower to effectively implement IPM methods before pest pressure became economically damaging. Analyzing the yield and demand of crops throughout the season allowed the grower to determine the cost-effectiveness of IPM techniques and prioritize the techniques used for the crops.
Cucumber Beetle in Dahlias
Exclusion Methods
During year one, after finding that vacuuming was not a realistic use of time, a popular exclusion method was attempted on sensitive varieties: blossom bagging. Quickly thrips filled the bags where they were protected from their natural predators, Orius (Minute Pirate Bug), pausing bagging as the primary control. Monitoring methods were adapted to include a weekly 10-flower sample count to track thrips activity in the dahlias. Once thrips pressure receded, blossom bagging commenced on sensitive varieties. While these bags did significantly reduce losses from cucumber beetle they were also very time consuming to apply and remove. On the farm, a wider mesh netting was used to protect entire beds of chrysanthemums from cucumber beetle. This netting was found to not result in additional thrips infestation and with less time taken per bloom so it was adopted as the primary exclusion method on dahlias.
In year two, the farmer started the dahlia season utilizing this wider gauge netting to cover entire rows of sensitive varieties. While Orius counts in Dahlia were less abundant in 2024 (due to the lack of exclusion in 2023), resulting in higher populations in the blooms, they were still present under nets in 2024 and active enough to suppress thrips populations and severity below damaging levels. Some damage from the netting was seen on the dahlia petals where the blooms touched the nets due to the zigzag planting of the dahlias in the rows.
In year three, the grower made changes to the design of the insect netting structure to reduce losses from the netting itself. Sensitive dahlias were planted in single rows providing ample space for plants to grow without risk of pressing against the net. The structure itself was be reinforced with "hoops" made of t-posts with PEX hose arches attached to posts with hose clamps. Arches were reinforced with a bailing twine purlin to ensure the netting can float above the blooms and secured at either end of the bed. Netting was secured with clamps at the base of posts. To harvest, one side of netting was gathered and clamped high on the posts, allowing easy access to the plants. The method reduced the labor time of an exclusion method per bloom greatly over blossom bagging and allowed the farmer to chose a mesh that was appropriate to allow for beneficial predators.
The refined approach for managing cucumber beetle and thrips in dahlias for 2024 included the new mechanical exclusion material to allow entry of thrips' natural enemies, an adjustment to our planting strategy for the sunflower trap crop to improve the stand, and a change to our method of cucumber beetle monitoring in the trap crop to protect natural enemies.
Trap Crop
During year one, a sunflower trap crop was planted in addition to sticky cards and lures as the biological method to reduce losses. Challenging weather at the start of season one resulted in delayed the timing of a direct seeded sunflower trap crop. Sticky tape was also found to catch beneficial insects in addition to predators so the grower opted to not include sticky cards in year two's design.
In year two, the grower adjusted the planting strategy for the sunflower trap crop from direct seeding, which resulted in skimpy stands in 2023, to greenhouse plug production in 2024, which resulted in full stands and successive rows of flowering sunflowers in time with the flowering of the dahlias. To reduce natural enemy losses in the sunflower trap crop to sticky traps around lures meant for cucumber beetles, the scouter did not use the sticky traps, used only lures (replaced during the season), and swept the sunflowers for cucumber beetle counts to monitor pressure levels. These methods were repeated in year three.
Assessing Effectiveness
In designing the project, the grower intended to use losses as a primary indicator of effectiveness of the changes being made. The grower initially estimated that losses from cucumber beetles before this research were $3,340. At that time, no formal monitoring system was in place, so that number was pure estimation. After attempting to track all losses in year one of this research, the grower found that losses had surpassed that estimation well over twofold, coming in at $8,895. The reasons for this are likely a combination of estimating 2022 losses without monitoring and shifts in growing conditions after significant el niño winter storms. The grower and technical advisor/crop scouter also hypothesize that given the multiple harvesters and the challenges of counting deadheads while also cutting to order, it was difficult to be sure that the deadhead count from cucumber beetle damage was accurate. Comparing losses but not accounting for increased production of sensitive varieties as the farm became more successful at reliably producing undamaged blooms was also an issue. As the project continued into it's last year (2025), the grower and crop scouter decided it was best to assess effectiveness of methods based on the scouter's ten flower per week sample rather than financial loss.
Fusarium in Lisianthus
The grower had experienced significant loss due to Fusarium in lisianthus before this research, but as a high-demand flower, it is appealing to research the potential for reducing those losses. In year one, cultural methods to increase drainage and airflow were implemented at the planting stage. Plugs were planted in tall beds with plugs planted high and reduced planting density from six inches to eight inches. A Trichoderma inoculant was intended to be used only at the plug stage but was added monthly through drip irrigation.
The much wetter than usual 2022-2023 winter in Central California delayed planting these plugs, leading to rootbound plants. Weekly rogue counts from rootbound plants were added to severity monitoring to better encapsulate the challenges Lisianthus faced in year one. Plants that did survive being rootbound were symptomatic of Fusarium despite these cultural and biological methods. Flowers were still sold selectively, but overall loss was still estimated at $568 due to fusarium. After loss from rootbound plants was estimated to be more than double that from fusarium ($1,256), it's fair to say that rootbound plants are another key pest of lisianthus and were addressed in year two.
To better identify the feasibility of growing lisianthus organically in this location, irrigation water was tested for Fusarium. A negative result determined that the last change the grower could make to reduce loss from Fusarium in year two was to plant in containers with clean media. Otherwise, the same preventative cultural methods used from the start would be implemented, along with the added monthly Trichoderma chemigation. To reduce loss from rootbound plugs, plants were to be inspected and planted within a few days of receiving them.
Year two was a significantly smaller planting of lisianthus due to the complexity and expense of container production versus field production and meant to test the economical and practical potential for disease-free lisianthus production. Purchased plugs were planted into sanitized bulb crates filled with new, clean media a few days after arrival. Trichoderma was applied 1 week via chemigation through the drip lines and again monthly during the warm growing season. The planting progressed normally until early symptoms of Fusarium began to express in July 2024. Tissue samples were taken to the lab and received a result for Fusarium avenaceum, a different species of Fusarium than was initially identified in 2022 by the Agriculture Commissioner's laboratory. The technical advisor has since learned that Fusarium contamination has been found in plugs ordered from nurseries, presenting a potential inoculum source.
Very few rootbound plants were discovered during the growing season, and we determined that this was not a significant key pest in 2024.
Overall, the planting performed similarly to previous in-ground plantings, expressing Fusarium symptoms and being generally unsaleable due to foliage and petal discoloration and uncertain shelf life. The grower and the technical advisor have concluded that it is not feasible to effectively manage Fusarium symptoms organically in lisianthus on this farm and that the likelihood of purchased plugs being infected is very high. Growing lisianthus from seed is extremely challenging and adding that to the already expensive nature of container planting, it has been determined that this portion of the research is prematurely complete. Year three did not include lisianthus in the study.
Bacterial Blight in Zinnias
While zinnias had been a successful crop for the grower, bacterial blight was a primary cause of the premature end to their growing season. This caused it to be identified as a key pest of zinnias, and cultural and biological methods were identified to research. Increasing drainage and airflow and a Trichoderma inoculant were the cultural and biological controls planned for year one. The grower would typically top zinnia beds with weed control fabric as they do with all annuals spaced at eight inches or wider. While useful for weed control, the fabric decreases airflow to the soil and can hide the pooling of water underneath due to gopher damage to drip lines, which was hypothesized to increase the proliferation of blight. Zinnia plants were planted at a wider one-foot density without fabric, although there was some variation in how many rows per bed were used due to inconsistencies in the bed top dimensions. Plants were dipped in a Trichoderma inoculant before planting as planned, and additional monthly inoculant through the drip irrigation was added as well.
As the season progressed, another pest emerged: Sclerotinia. Weekly severity monitoring was coupled with rogue counts to quantify losses to either pest. This rogue counting also clarified that two-row beds experienced a significantly lower rate of loss from both Blight and Sclerotinia (86 plants loss from a combination of the two pests in two-row beds and 647 plants lost in three-row beds). For year two, all beds were planted in two rows with one-foot spacing.
After seeing significant gains in our 2023 trials, the approach for 2024 was similar to 2023. Once again zinnias were planted in an area that had no prior zinnia planting, plugs planted high in tall beds with reduced plant density, treated with a biological soil inoculant at planting and monthly throughout the growing season. The refinements we made for 2024 were to plant in all 2-row beds to encourage additional airflow to discourage Blight and Sclerotinia in the crop and limit to a single planting of zinnias.
In 2024, the farm benefited from a shorter rainy season that allowed beds to be built and plants to be installed without rain or other delays. The bed residue was insignificant enough to minimize bed destruction during weeding. The crew kept the zinnias clear of weeds throughout the main harvest season. The high planting helped encourage drainage and kept water from pooling at the base of the stems. As the plants grew, their height and the high planting caused some plants to fall into the furrows. Tricoderma was applied to the zinnias every month for three months. This was one treatment more than 2023. This was meant to inoculate the soil with beneficial bacteria that may protect the plants' roots from Blight during increased pressure from high temperatures.
Overall, there were fewer losses to Blight and Sclerotinia in 2024. However, 2-row planting may have increased losses to fallen plants due to lack of stability from other surrounding plants. Plants were not trellised, and some losses were associated with fallen plants.
For 2025, the grower continued to plant the zinnias in 2-row beds, planting plugs high in tall beds, using a biological soil inoculant treatment at planting and monthly throughout the growing season, and rotating into an area not previously planted in Zinnias. The grower opted to not trellis the zinnias due to the large quantity of plants and strain on labor during the summer months.
Research outcomes
Cucumber Beetles in Dahlias
After trial and error, the grower found that exclusion was the most effective method for reducing loss from cucumber beetle using netting over the entire row of sensitive plants. In order to help and not harm the dahlias, it is crucial that the netting allows for entry of Orius or Minute Pirate Bug, a natural predators, so as to not inadvertently create a haven for thrips. It's also important that the netting does not touch the blooms. Dahlias planted under netting should be planted single-file to reduce the width of plants in the bed. To reduce drooping, the structure must include vertical posts and hoops, along with a horizontal purlin connecting hoops.
Planting a sunflower trap crop adjacent to the dahlia patch is an effective way to attract cucumber beetles elsewhere and presumably reduce their impact on the dahlias. While it was hard to prove this quantitatively, it was observed that cucumber beetles were present on the trap crop.
With the combination of excluding cucumber beetles from sensitive plants and attracting them to a trap crop, the grower has been able to increase production of sensitive varieties, producing a reliable supply of dahlias for their florist customers including hard-to-grow white varieties.
Blight (and Sclerotinia) in Zinnias
Loss from blight and Sclerotinia in zinnias can be effectively reduced through cultural changes to planting conditions. The farmer significantly reduced planting density to two lines at one foot spacing on uncovered tall beds irrigated through drip lines and found a noticeable decrease in losses from blight and Sclerotinia over the natural growing season of zinnias in their area. In order to grow without weed fabric at the scale of the farm's typical zinnia production (around 6,000 plants) it's crucial to implement other weed prevention methods typical in organic farming. Flame wedding prior to planting and tractor cultivation are both helpful so that reduced losses from disease are not met with increased labor cost from hand weeding.
Zinnia plant health was also supported through application of regular Trichoderma inoculant but due to the nature of the research, it's unclear the exact effect of this treatment.
Fusarium in Lisianthus
Unfortunately, this research showed that it is not currently possible to organically and effectively reduce losses from Fusarium in lisianthus if the conditions support the disease. Cultural changes to growing practices that increase airflow, an experimental attempt to grow in purchased medium and a regular Trichoderma inoculant still resulted in significant losses. The opinion of the testing lab and the grower's experience suggests that purchased plugs may be infected with Fusarium at the time of arrival so even significant measures to control for contamination between native soil and the plants aren't helpful. Rootbound is also a significant factor in the success of lisianthus and plants can demonstrate similar symptoms to Fusarium if rootbound at planting.
While disappointing, this result was ultimately helpful in clearly demonstrating a cost saving decision: to stop trying to grow something that will likely never be successful.
Education and Outreach
Participation summary:
Research findings have been shared through five events. The first event was an on-farm event attended by 30+ other growers. Grower Kelly Brown and technical advisor Jessica Vaughan discussed the project in English and Spanish with the actual crops present for view and led an engaged discussion. The second event was held off the farm at nearby Cabrillo College Horticulture Department using a slides presentation. Fifty growers, including twenty-five of the ALBA (Agriculture and Land-based Training Association) students, attended with simultaneous translation into Spanish. The third event was a an on-farm event attended by 28 growers and educators, introducing the approach to year two's research. The forth event took a slightly different approach, framing the research in the broader concept of the Pest Triangle, adapted from The Disease Triangle (Agrios 2005). Then, the project's approaches to ecological integrated pest management for each crop were described in terms of the three sides of the triangle: host, pest, environment. This event was once again held at Cabrillo College using a slides presentation and attended by 18 growers and educators. The final event was a virtual presentation comprised of a slide presentation and talk by Kelly Brown and Jessica Vaughan. This presentation was recorded and is available on YouTube for future viewing. All events included handouts and follow-ups with information about monitoring techniques.
Kelly Brown and Jessica Vaughan co-authored an article for the Cut Flower Quarterly, a publication of the Association of Specialty Cut Flower Growers. This article, as well as an interview with Kelly Brown about the grant process, appeared in the Summer 2024 issue. Brown wrote a second article, printed in the Summer 2025 issue, for the Cut Flower Quarterly using the Pest Triangle framework to explain the research.
Research has also been shared through Instagram posts. With nearly 5000 followers, many of whom are also flower growers, this is a helpful tool for connecting with growers at a distance as well as promoting events.
Holding two events during the first year, one on farm and one off proved to be a convenient point of comparison in regards to what demographics are able to participate. The farm is located on the opposite side of the Santa Cruz County from the southeastern area more densely populated with a large Latino farm worker community. This hour drive may have been an important factor in less BIPOC representation at the on-farm event held in June 2023. The off-farm event in February 2024 on the other hand was held at Cabrillo College, a short fifteen minute drive from the primary agricultural area of Santa Cruz County, was half Spanish-speaking Latino farmers participating in the ALBA, Agriculture and Land-Based Training Association program. The Cabrillo Horticulture Department coupled the event with a tour of their educational farm providing information about their classes. In this sense the event acted as a bridge between the ALBA students and further agricultural education available to them. Holding events both on and off the farm encouraged the research to reach a broader range of farmers, especially those Latino workers who have been traditionally excluded from educational settings while providing a majority of the farm labor.
In 2024, more educators attended events as word spread that this research was taking place. After Christof Bernau of the UC Santa Cruz Center for Agroecology attended an on-farm event, he brought current ALBA, Agriculture and Land-Based Training Association, farmers to a special farm tour and presentation by Kelly Brown. That same year, Brown was also approached by Ellie Andrews who serves vegetable & cut flower growers in Sonoma, Marin, and Napa Counties as the UC Cooperative Extension Specialty Crops Advisor to contribute to a presentation about cucumber beetle prevention. Andrews found this grant research through the Western SARE database. Screenshots of the Instagram info graphics produced in 2024 were included in the presentation along with a summary of findings provided by Kelly Brown. In the Spring of 2026, Adrienne Frisbee, an attendee taught the Pest Triangle using the perspective and findings of the 2024 Cabrillo event to her horticulture students at Cabrillo College. After the final virtual event in 2026, Katharina Ullman, who provides technical support to organic growers through University of California, shared finding with other providers.
Information about the research shared through the Cut Flower Quarterly reaches English-speaking farm owners as the publication is only shared to dues-paying members of the Association of Specialty Cut Flower Growers. Through Instagram, posts are engaged with in English by other growers. This forum is essentially a question and answer format with opportunity for crowdsourcing among other account holders.
Education and Outreach Outcomes
The overarching recommendation about effectively disseminating agricultural research results is the importance of multiple modes of communication, greater geographical access, time flexibility, and multiple languages. Especially since Do Right is at the very north tip of Santa Cruz County, offering events that were more centrally located as well as on farm helped share with more people based in different locales which resulted in bringing in a more racially and socioeconomically diverse demographic of people. Offering a virtual recorded event was a way to decrease all geographical and time barriers. By making an effort to provide bilingual access, the project was available to nearly twice as many local farmers.
The cut flower industry is far behind other agricultural sectors in terms of sustainable agriculture. Besides the overall reach, the project help spread the conversation of Integrated Pest Management including the usefulness of field scouting into the cut flower world. The project highlighted IPM in the major North American publication for cut flower growers, where organic growing is definitely not the norm. The project also tranformed the very specific question of reducing losses at Do Right and expanded it to illuminate broader concept of the Pest Triangle so that other growers and educators can apply this perspective elsewhere. The project provided practical insight into how to identify pests and disease, first-hand accounts of a farmer's struggle and walked through practical solutions including when to stop growing a crop.