Evaluating Thrips Spray Programs in Florida Strawberry: Population Impacts and Fruit Quality1/20/2026
At the Florida Strawberry Growers Association’s Annual Tailgate in Dover, FL on January 14th, Dr. Jason Hamm of Florida Ag Research shared current findings from field work evaluating insecticide spray programs for chilli thrips management in Florida strawberry, with a focus on thrips populations, fruit quality, and practical sampling considerations.
Why early-season thrips management is a focal point
Chilli thrips populations can build quickly in the first third of the season. Early sprays do not always prevent damage to foliage, blossoms, and fruit, which is why the current strategy emphasizes early intervention—applications during the first month of establishment (before canopy closure) to improve coverage and delay population buildup. Field trials are currently underway at the Dover FSGA Research Site to refine early-season application methods under real-world conditions, including examining products and modes of action targeting oviposition, eggs, and immatures. Trial overview and what was evaluated In this study, ‘Ember’ strawberry was planted 10/20/2025, and five treatments were compared: four rotation programs plus an untreated check (UTC). 
Applications and Assessments
Assessment methods included:
Key findings (early-season conditions)
1. Population control vs. crop protection can diverge Across assessments focused on adults + larvae per flower, the data indicated that IGR-based approaches provided stronger thrips population reduction relative to systemic and contact products in this dataset. 
2. Fruit protection and marketable outcomes favored systemic programs in this early window
When looking at harvested fruit outcomes after three harvests, the presentation notes that a program with systemic products provided the best fruit protection under the early-season conditions observed. Marketable yield results were also summarized with an emphasis on early-season ROI dynamics, noting that systemic products can provide strong ROI compared to other rotations, though the untreated check performed similarly under these specific early-season conditions. 
3. Sampling location matters (flowers vs. foliage)
The work also addressed the practical question: Where should you sample, flowers or foliage? The dataset presented a comparison of adults + larvae per leaf and summarized percent control by program. Separately, the presentation’s conclusions noted more thrips found in blossoms vs. foliage in these plots.
Conclusions and Next Steps
The presentation closed with several clear takeaways:
 Florida Ag Research is launching a dedicated research program evaluating the efficacy of biostimulants in Central Florida strawberry production. Candidate products will be field assessed in small plot trials and larger demo plots for marketing support in the heart of the Southeast strawberry growing region. Biostimulant evaluation protocols will measure improvements in:
These investigations will detail effects of application rate, phenological timing, soil or foliar treatment, and almost any other specific product usage scenario for the manufacturer.
Using your protocol or ours, these studies begin at planting in October and continue through the fruiting season ending in March 2026. Plant growth rates, root development, flowering, and fruiting parameters are recorded on populations of treated plants compared to untreated ones. Complete materials and methods, statistical and graphical presentation of data, and interpretation of results are provided in the final report. Florida Ag Research has the capability to apply biostimulant products as a soil amendment, chemigation application, or foliar spray. To capture physiological responses, our trials incorporate advanced measurement tools including the LI-COR® LI-600 Chlorophyll Content Index sensor, NDVI/NDRE sensors, WinRHIZO™ root scanner, and experienced field technicians familiar with strawberry quality standards and measurement. These technologies and staff allow us to quantify crop growth patterns, stress response, and canopy health with repeatable precision. We welcome inquiries from product developers and invite you to connect with our team for more information on our biostimulant program. Chilli Thrips Control in Strawberry: Comparison of Conventional and Organic Treatment Efficacy5/13/2025
Justification: Chilli thrips are increasing in severity and distribution in Florida’s strawberry industry every year, and reports of severe crop injury are commonplace in all strawberry production districts statewide. In warm fall years, Chilli thrips can become established in strawberry plantings during plant setting periods of overhead irrigations when foliar insecticide spray applications are not possible. Within the first trimester of the crop, most strawberry plantings are infested with rapidly increasing populations of these pests, with injury to foliage, blossoms and fruit evident by mid-season. This occurs despite repeated insecticide sprays or inundative releases of hundreds of thousands of predatory mites and/or beneficial insects. One strategy proposed is to apply insecticides (conventional or organically approved) as early as possible before plant canopies are established and spray coverage limits control. If insecticide materials could be used during the first month of crop establishment, thrips populations could be delayed, and plant damage minimized later in the season. This project seeks to test insecticide application methodologies during the critical crop establishment period under actual field conditions at the Dover lab.  Photo 1. Close up of Chilli Thrips (Scirtothrips dorsalis) on strawberry leaf (left) and the feeding damage on infested strawberries rated a 5 on a 0-5 scale (right) Methodology: Three experiments were carried out on naturally infested Brilliance strawberries transplanted in October 2024 at the Dover research station. All three experiments include untreated check plots and a grower standard foliar insecticide rotation.
Treatments: Conventional systemic insecticides
Organic products (1-2 applications)
Data Collection: Thrips counts on ten blossoms per plot were reported weekly. Feeding damage on fruit was rated on a 0-5 scale, where 5 is severely damaged (see photo 1). Early Season Chilli Thrips Counts* on FlowersPre-Plant dips for Cyantranilprole and Imidacloprid had the fewest thrips on flowers in the pre-plant conventional program.
Post-plant Conventional treated strawberries saw the fewest Chilli thrips on standard tank mix program.
Strawberry blossoms treated with experimental organic programs saw higher average Chilli Thrips than the standard and untreated plants.
*Time weighted average count, six week total pressure. Larvae, adult and combined counts analyzed separately Average Fruit Damage % Control
Pre-Plant: Imidacloprid as a Preplant Dip controls fruit damage better than standard, statistically (p<0.05)
Post-Plant: Night sprays were significantly less effective than sprinkler or drip applications for experimental treatments (p<0.05)
Organic: No significant differences for standard rotation or experimentals  Results: The abnormally cool temps in November and December delayed Chilli thrips establishment until mid-January at Dover. As a result, foliar populations remained very low for the first 5 weeks of the season and comparison of insecticide efficacy during crop establishment was not possible on leaves alone. However, beginning weekly in December, blooms were sampled along with foliage and Chilli thrips were recovered in low but quantifiable densities to compare treatments after plants had set and irrigations stopped. Conclusions: Chilli Thrips populations were low in 2024, limiting the conclusiveness of insecticide efficacy data. However, evaluations based on Chilli thrips presence in blooms and fruit damage indicated that the systemic insecticides Imidacloprid and Cyantraniliprole demonstrated efficacy against both nymphs and adults. Although efficacy was demonstrated rates used for dip and drench treatments negatively impacted plant growth and delayed crop development. The use of insecticide plant dips and drip chemigation methods is not recommended currently due to potential phytotoxicity effects. None of the organic insecticides tested provided observable control under the conditions of this study. Further research is planned for Fall 2025 to determine safe and effective rates for soil-applied insecticides and to reassess efficacy under higher pest pressure.
Want to find out more, download the full PowerPoint Presentation.
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