Amblyseius cucumeris - Thrips & Mite Preventative Control

Target Pests

Primarily targets:

• Young thrips larvae across many species including:
  • Western flower thrips
  • Eastern flower thrips
  • Onion thrips
  • Greenhouse thrips
  • Melon thrips

Secondary/occasional prey

• Broad mites
• Cyclamen mites
• Tomato russet mites
• Some other plant-feeding mites

A. cucumeris may also feed on spider mites, but it isn't a spider mite control. For an established infestation, use a specialist such as Phytoseiulus persimilis or Neoseiulus californicus.

Pairing for Complete Thrips Control

A. cucumeris is primarily a predator of first-instar thrips larvae. It is not a stand-alone solution for a heavy infestation containing large larvae and adults.

• Adding Sf beneficial nematodes will help with soil dwelling stages of thrips.
• For heavy thrips pressure, Orius insidiosus (Minute Pirate Bug) brings in a generalist predator that also takes on adult thrips.
• Once temperatures climb past 80°F, switching to or adding A. swirskii keeps coverage going through the summer.

What Cucumeris Mites Are

A. cucumeris is a generalist predatory mite that feeds primarily on small prey such as thrips larvae and can also survive on pollen or other food sources when prey is scarce. It stays active at lower temperatures than most predatory mites, so it can be working before pest pressure builds with the heat.

How It Works

Females tuck their eggs onto the fine hairs along leaf veins on the undersides of leaves, the same zone where thrips larvae feed. The eggs hatch and the young mites begin hunting and keep feeding until they reach adulthood. At 66–80°F and suitable humidity, eggs hatch in a few days and young mites reach adulthood in about 10 days. Adults live 4–5 weeks, so feeding and egg-laying overlap continuously. With suitable food, temperature, humidity, and habitat, populations can reproduce and provide continuing protection. Preventive releases and periodic reintroductions may still be needed.

When to Use Cucumeris

A. cucumeris does its best work as a preventive release, placed early in the season before thrips and spider mite populations have a chance to establish. A. cucumeris tolerates cooler conditions better than many biological-control predators, making it useful for early-season and cool-growing environments. Development and reproduction are strongest at 66–80°F.

How to Choose Between Cucumeris and Swirskii

Choose based on your space's temperature.

• A. cucumeris covers the cooler end, 54–80°F.
• A. swirskii takes over from 68°F up to the mid-90s and adds whitefly control.

As temperatures rise, consider transitioning from A. cucumeris to A. swirskii. A. swirskii performs better under warmer conditions and also adds whitefly eggs and young nymphs to its prey range.

Safe, Sustainable Pest Management

• No synthetic pesticides
• Safe around people and pets when used as directed
• Safe for use on edible crops when used as directed
• Fits seamlessly into existing IPM programs

Release Methods

Bottled Predators: Fast Coverage

• Delivers a concentrated dose of predators in a carrier you sprinkle directly onto foliage
• Works indoors or out: houseplants, gardens, greenhouses, and larger growing operations
• Re-introduce every 1–2 weeks as needed

Slow-Release Sachets: Prevention & Maintenance

• A small breeding colony inside each sachet releases predators gradually over 2–4 weeks
• Low-effort way to maintain standing protection between active treatments
• Hang it and let it work, with no repeated handling for weeks at a time

Each sachet also holds tiny feeder mites. They're harmless and don't eat plants; they're there as an instant food source for the young predatory mites developing inside.

Pro Tips

Good Bug Supplemental Diet

When pest numbers are low, hang Good Bug Supplemental Diet tabs near your release so predators still have food and stay on your plants. Contains shellfish (Artemia).

Hanging Boxes for Bottled Mites

Pour bottled mites into hanging release boxes to keep them where the pests are and keep the carrier dry. Sachets already hang on their own.

Chemical Compatibility

Sprayed recently? Some pesticides harm predatory mites for days or weeks after they dry. Check which chemicals are safe for predatory mites and how long to wait before releasing.

Application Rates

These are general starting points. Adjust based on pest species, plant type, and infestation severity, and monitor pest and predator populations regularly to gauge how the program is working.

Bottled Mite Release: Fast Coverage

• Light infestation: 5–10 mites per sq. ft.; every 1–2 weeks
• Heavy infestation: 10–15 mites per sq. ft.; every 1–2 weeks

For heavy infestations, don't rely on increasing the A. cucumeris rate alone. Combine with other compatible controls and reduce the pest population through an IPM approach.

Slow-Release Sachets: Prevention & Maintenance

Sachets are a preventive tool, so one rate covers most situations:

• Plants touching: hang 1 sachet per 3–6 sq. ft.
• Plants not touching: hang 1 sachet per plant.
• Replace every 2–4 weeks.

Temperature & Humidity Range

Effective range: 54–80°F (best 66–80°F)
Humidity: 65–72%

A. cucumeris eggs are sensitive to dry air. Maintain adequate humidity, especially around sachets and young plants. Avoid allowing sachets to dry out completely, but don't keep foliage continuously wet.

Application Instructions

Bottled Release

1. Release in the early morning, in the evening, or when lights are off.
2. Clear away any webbing on infested foliage first.
3. Mist leaves lightly before releasing.
4. Sprinkle the bottle contents directly onto plants, or use hanging boxes to keep predators concentrated in target zones.
5. Leave the open container in place for 72 hours so any remaining predators can disperse.
6. Repeat every 1–2 weeks until the infestation is under control.

Sachet Release

1. Choose the plants where you want standing protection.
2. Hang each sachet within the canopy, touching foliage so predators can walk directly onto the plant, and out of direct sunlight.
3. Keep sachets from drying out completely, but avoid spots where they'll stay soaked, since constant dampness can encourage mold.
4. Replace every 2–4 weeks.

For best results, release as soon as your order arrives. If you need to wait, hold them for no more than 8 hours at 55–65°F, out of direct sunlight. Don't refrigerate them, and keep sachets out of coolers and air-conditioned rooms, which dry them out.

Is it too cold to release A. cucumeris in early spring?
A. cucumeris can remain active in relatively cool conditions, but development and reproduction slow as temperatures fall. For best establishment, aim for 66–80°F when you can.

Why use A. cucumeris before I even see thrips?
Thrips hide in buds and leaf folds, so damage usually appears after the population is established. A. cucumeris can live on pollen until thrips arrive, so releasing early puts predators in place to catch the first larvae before they multiply.

Can I use A. cucumeris with neem oil or insecticidal soap?
Not while predators are present. These products can kill predatory mites through direct contact, and some treatments may remain harmful after the spray has dried. Check which chemicals are safe for predatory mites and observe the recommended re-entry/release interval before introducing predators.

Are A. cucumeris predatory mites safe for people, pets, and plants?
When used as directed, yes. A. cucumeris isn't known to bite people or pets, and it doesn't feed on plants. It eats small pests and pollen, and its numbers fall once food runs out.

What are the other tiny mites in my sachets?
Those are feeder mites. They're harmless and don't eat plants. They're packed in with the cucumeris as an instant food source, so young predatory mites have something to eat while they develop.

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