Thrips parvispinus, also known as pepper thrips or Taiwanese flower thrips, has emerged as a significant pest in U.S. greenhouses since its first detection in Florida in 2020. Michigan growers have reported infestations since 2023, raising concerns about crop losses similar to those seen in Thailand, where this pest severely impacts pepper production. Unlike western flower thrips (Frankliniella occidentalis), T. parvispinus causes extreme leaf deformation, scarring, and stunted growth, often rendering plants unsellable.
Identification and Damage
T. parvispinus is distinguishable by its dark head, beige thorax, black abdomen, and yellow legs. Females exhibit a two-toned appearance, while males are smaller and uniformly yellow-brown. Their feeding damage resembles broad mite injury, with brittle, puckered foliage and distorted flowers (Photo 1).
Key Hosts:
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Ornamentals: Mandevilla, Gardenia, Anthurium, Hoya, Schefflera, orchids, Ficus, Gerbera, Poinsettia
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Vegetables & Fruits: Peppers, citrus, eggplant, strawberries
Life Cycle and Behavior
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Development: 13–14 days (slower than western flower thrips).
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Eggs: ~15 per female, laid in bract leaves, leaving brown spots.
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Pupation: Occurs in soil (~1 inch deep).
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Survival: Cannot withstand sustained temperatures below 50°F, making outdoor overwintering unlikely in Michigan.
Current Research and Management Strategies
Dr. Alexandra Revynthi (University of Florida) leads research on T. parvispinus control, evaluating chemical, biological, and cultural methods.
1. Chemical Control
12 Most Effective Conventional Insecticides:
| Trade Name | Active Ingredient | MoA Group |
|---|---|---|
| Avid | Abamectin | 6 |
| Conserve | Spinosad | 5 |
| Hachi-Hachi SC | Tolfenpyrad | 21A |
| Mainspring GNL | Cyantraniliprole | 28 |
| Orthene 97 | Acephate | 1B |
| Overture | Pyridalyl | Unknown |
Top Biopesticides:
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M-Pede (potassium salts of fatty acids)
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Sesame oil (Bee Safe 3-in-1)
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Ultra-Fine oil (mineral oil)
2. Microbial Insecticides (Entomopathogenic Fungi)
Promising results from lab tests (pending greenhouse validation):
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Wettable Powders: Isarid, Ancora, Bioceres
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Liquid Formulations: Lalguard M52, Velifer, BotaniGard ES
3. Beneficial Nematodes
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Heterorhabditis bacteriophora (50% mortality in lab)
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Steinernema riobrave & S. carpocapsae (effective in greenhouse trials)
4. Biological Control Agents
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Predatory Mites:
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Amblyseius swirskii (4 larvae/day)
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A. degenerans (6 larvae/day)
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Anystis baccarum (14 thrips/day)
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Minute Pirate Bugs: Effective against larvae & adults
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Lacewings: Strong against early instars
Future Research Directions
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USDA & University Studies: Investigating overwintering potential in U.S. fields.
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Ongoing Trials: Refining biopesticide and biocontrol efficacy under real-world conditions.
Thrips parvispinus poses a unique challenge due to its severe damage and resistance to some conventional controls. An integrated pest management (IPM) approach—combining chemical, biological, and cultural strategies—is essential. Early detection, proper scouting, and rotating control methods will be critical for Michigan growers facing this emerging pest.
Key Takeaways:
Monitor new growth for early signs of damage.
Rotate insecticides to prevent resistance.
Combine biocontrols (predatory mites, nematodes) with chemical treatments.
Stay updated on ongoing research for new solutions.
