Evaluating Thrips Spray Programs in Florida Strawberry: Population Impacts and Fruit Quality

​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

• Application timings: 12/22, 12/31, 1/7

Assessment methods included:

1. Thrips counts on leaves (emerging trifoliate)
2. Thrips counts on blossoms (five blooms per plant; alcohol bath; microscope counts)
3. Fruit evaluations (% thrips damage on harvested fruit)

The rotation programs represented different scenarios (including conventional rotations, a multiple-MOA approach, and an organic program), framed around IRAC mode-of-action considerations.

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:

• Relatively low thrips populations in our plots despite our best efforts
• More thrips found in blossoms vs. foliage
• IGR’s provide better population control, but systemic products protect marketable yield better in early season conditions
• Continue to characterize population dynamics of thrips in real-world conditions and understand how IGR’s fit into management programs