Amblyseius andersoni - Wide-Temperature Spider & Russet Mite Prevention

Target Pests

Primarily targets:

• Spider mites, including two-spotted spider mites, carmine mites, Lewis mites and Banks grass mites
• European red mites and citrus red mites
• Russet and rust mites, including tomato russet mites and hemp russet mites
• Broad mites and cyclamen mites

Secondary/occasional prey

• Young thrips larvae
• Pollen, honeydew and fungi when prey is scarce

A. andersoni is not a thrips control. For thrips, use A. cucumeris in cooler conditions or A. swirskii in warm ones.

Pairing for Heavy Spider Mite Pressure

A. andersoni works best while mite numbers are low. It knocks back small colonies before they explode, but it isn't a stand-alone answer for a heavy infestation.

• For webbing-heavy hot spots, add Phytoseiulus persimilis, a spider mite specialist.
• For steady pressure in heat or drier air, add Neoseiulus californicus.
• Stethorus punctillum (Spider Mite Destroyer) is a predatory beetle with a big appetite for spider mites.
• Feltiella acarisuga flies to spider mite colonies other predators can't reach.

What Andersoni Mites Are

A. andersoni is a generalist predatory mite, less than 1 mm long, tear-shaped and beige to light brown. Its color shifts with what it has been eating. Because it can live on pollen when prey is scarce, it can be released before pests arrive and still hold on in the crop.

How It Works

Every stage after the egg hunts: larvae, both nymph stages and adults feed on spider mite eggs, young mites and adults. Females lay single eggs on leaf hairs on the undersides of leaves, near pest colonies. Eggs hatch in 2–3 days, and young mites reach adulthood in about 8–12 days in summer conditions. Adults live about 3 weeks and each female lays 25–30 eggs.

When to Use Andersoni

A. andersoni does its best work as a preventive release, placed early in the season before spider mites and russet mites build up. It handles a wider temperature swing than most predatory mites, so it suits outdoor gardens, orchards and greenhouses where temperatures rise and fall. As days shorten in early fall, andersoni can go dormant until conditions improve.

Where It Works

• Crops: strawberries, raspberries, blueberries, grapes, fruit trees, citrus, tomatoes and other vegetables, hemp, ornamentals and tree nurseries
• Settings: greenhouses, indoor grow rooms, gardens, orchards and fields
• Moves easily on hairy-leaved plants such as tomatoes, where many predators struggle

Andersoni or Persimilis?

Choose by the job.

• A. andersoni is a generalist. It eats several kinds of mites and pollen, handles 47–104°F, and stays put when prey is scarce, so it's built for prevention.
• Phytoseiulus persimilis is a spider mite specialist. It eats spider mites faster and works inside their webbing, but it needs spider mites to survive, so it's built for an active outbreak.

Many growers use both: andersoni for standing protection, persimilis for hot spots.

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

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: 2–5 mites per sq. ft.; every 1–2 weeks
• Heavy infestation: 5–7 mites per sq. ft.; every 1–2 weeks

For heavy infestations, don't rely on increasing the A. andersoni rate alone. Combine with a spider mite specialist 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: 47–104°F
Humidity: 60–90%

Keep sachets from drying 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. Lay the bottle on its side and gently roll it to mix the mites through the carrier.
5. Sprinkle the bottle contents directly onto plants, or use hanging boxes to keep predators concentrated in target zones.
6. Leave the open container in place for 72 hours so any remaining predators can disperse.
7. 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 on a stem at mid-height, inside the canopy and touching foliage so predators can walk directly onto the plant, and out of direct sunlight.
3. Keep the bottom of the sachet off wet surfaces, and avoid spots where it will 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.

Why use A. andersoni before I even see spider mites?
Spider mites multiply fast in warm weather, and by the time you see stippled leaves the colony is established. A. andersoni can live on pollen until mites arrive, so releasing early puts predators in place to catch the first colonies.

Will A. andersoni clear a heavy spider mite infestation on its own?
Usually not. It's built for prevention and small colonies. For heavy pressure or heavy webbing, add Phytoseiulus persimilis or Neoseiulus californicus and bring numbers down with an IPM approach.

Can I release A. andersoni in fall or winter?
As days shorten in early fall, A. andersoni can go dormant and stop hunting until temperatures and day length improve. For fall releases, a warm, well-lit greenhouse or grow room is the best fit.

Can I use A. andersoni 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. andersoni predatory mites safe for people, pets, and plants?
When used as directed, yes. A. andersoni 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.

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We do not provide recommendations on pesticide use. Products are sold for home use only, not commercial use.

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