How do I use Amblyseius cucumeris to control thrips in glasshouse?

Release Amblyseius cucumeris as a biological control agent. Typical rate: 50–100 mites/m² or 1–2 sachets/m². Repeat Top up every 3–4 weeks. Best performance is usually between 18–32°C.

How do I use Amblyseius montdorensis to control thrips in glasshouse?

Release Amblyseius montdorensis as a biological control agent. Typical rate: 50–100 mites/m². Repeat Repeat after 2–3 weeks in high pressure. Best performance is usually between 20–32°C.

How do I use Orius laevigatus to control thrips in glasshouse?

Release Orius laevigatus as a biological control agent. Typical rate: 0.5–2 bugs/m². Repeat Re-release after 2–3 weeks. Best performance is usually between 20–32°C.

How do I use Amblyseius cucumeris to control thrips in tunnel?

Release Amblyseius cucumeris as a biological control agent. Typical rate: 50–100 mites/m². Repeat Monthly top-ups during season. Best performance is usually between 18–32°C.

How do I use Steinernema feltiae to control thrips in glasshouse?

Release Steinernema feltiae as a biological control agent. Typical rate: 250k–500k nematodes/m² (media drench). Repeat Repeat every 2–4 weeks. Best performance is usually between 12–28°C.

Thrips

Orius + Amblyseius swirskii systems.

Thrips damage flowers and foliage. Swirskii + Orius provide season-long suppression...

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About Thrips

Thrips are small, fast-moving pests that feed by rasping and sucking plant tissue. In UK horticulture the main species of concern are the western flower thrips (Frankliniella occidentalis) and onion thrips (Thrips tabaci). These pests cause silvery scarring, distorted growth and can transmit plant viruses such as TSV and INSV, making early detection and biological control essential.

Symptoms of Thrips Damage

Silvery scarring on leaves, flowers or fruits
Small black faecal spots (“tar spots”)
Distorted growth and flecking on young tissue
Flower deformation and poor fruit set
Presence of tiny, slender insects when tapping foliage

Why Biological Control Works

Thrips have vulnerable larval stages that spend time on the plant surface or drop to the compost, making them ideal targets for predators and soil-dwelling beneficials. Two of the most effective agents are Orius laevigatus, a robust predatory bug that feeds on all thrips stages including adults, and Amblyseius swirskii or Amblyseius cucumeris, which target first-instar larvae.

Common UK Thrips Species

Frankliniella occidentalis — Western flower thrips (WFT)
Thrips tabaci — Onion thrips
Chaetanaphothrips signipennis — Banana thrips (occasionally encountered)

IPM Recommendations

Introduce Amblyseius predators early, before thrips adults establish
Use Orius for control of adults and to clean up flower hotspots
Place blue sticky traps to monitor incoming thrips pressure
Improve hygiene and remove old flowers where larvae hide
Mist lightly or raise humidity to disrupt thrips development
Maintain a preventative population of predators through the whole season

Preventative vs Curative Strategy

Preventative: Slow-release sachets of Amblyseius cucumeris or Amblyseius swirskii should be placed early in the crop, especially in propagation and young plants.

Curative: When adult thrips are abundant or when flower damage is visible, introduce Orius laevigatus for fast knockdown. Orius is particularly valuable in summer crops where thrips pressure spikes.

Environmental Notes

Amblyseius cucumeris performs well in cooler UK conditions
Amblyseius swirskii excels in warm summer crops and heated glass
Orius requires higher light levels to thrive—early introductions help
Low humidity and high temperatures accelerate thrips reproduction

Biological Controls for Thrips

The species below are examples of beneficial organisms commonly used against thrips. Recommendations are based on published biological control information and practical IPM experience. Always confirm suitability for your crop, growing system and local conditions before use.