Amblyseius andersoni - Warm-Season Spider & Russet Mite Control
How to Say It: am-blih-SY-us an-der-SOH-nye
Built for hot days and cool nights, with steady mite control all season.
Spider mites, broad mites and russet mites spread quickly once they get started. By the time you notice stippled leaves or fine webbing, the infestation is usually well established. Amblyseius andersoni is biological spider mite control that works ahead of the problem. This hardy generalist predator patrols your plants before pests build up and keeps working through the temperature swings that slow other predatory mites down.
It works well in gardens, greenhouses and grow rooms, and it moves easily across crops where many other predators have trouble getting around.
Meet Amblyseius andersoni
A. andersoni is a predatory mite used in integrated pest management (IPM) programs to keep plant-feeding mites in check. It is a Type II generalist: when pest mites are scarce, it can live on pollen and stay in your crop instead of dying off. Where pollen is limited, as in grow rooms, on houseplants or in crops that aren’t flowering, Good Bug Supplemental Diet Cards give it an Artemia-based food source between outbreaks. That staying power makes it a natural choice for preventive, season-long coverage. Its working range of 47°F to 104°F is one of the broadest among predatory mites, so it holds up in outdoor beds, unheated greenhouses and grow rooms alike.
Pests It Controls
Primary targets:
- Two-spotted spider mite
- Carmine mite
- Lewis mite
- Banks mite
- Grass mite
- European red mite
- Citrus red mite
- Broad mites
- Russet mite
- Rust mite
- Gall mites
- Hemp russet mite
Secondary targets:
- Cyclamen mites
- Thrips larvae
Amblyseius andersoni vs. Phytoseiulus persimilis
Both control spider mites, but they work in very different ways:
- A. andersoni is a Type II generalist. It can survive on pollen between outbreaks and tolerates a wide range of temperatures and humidity. It is best suited to preventive, standing protection.
- P. persimilis is a Type I specialist. It hunts only inside spider mite webbing and needs consistently high humidity (around 70% in the canopy) to reproduce. Where those conditions are right, it clears infestations faster.
Choose P. persimilis to clear an active hot spot in a humid greenhouse. Choose A. andersoni for steady, low-maintenance coverage all season.
How A. andersoni Controls Pest Mites
Females lay clear eggs on the undersides of leaves, close to pest activity. The eggs hatch in about 2–3 days. The young mites start feeding right away and reach adulthood in roughly 8–12 days in warm conditions. Every mobile stage feeds on pest mite eggs, juveniles and adults. Adults keep hunting for about three weeks, so each application builds a resident population that keeps working after the first knockdown.
When to Use It
A. andersoni does the most good when it goes on early, before pest mites take hold. Good times are at planting, after transplanting, or at the first sign of stippled leaves. Because it can live on pollen, it stays established through quiet stretches when there is little prey. For an infestation that is already active, start with bottled material at the heavy rate, or pair it with P. persimilis. Then switch to sachets for ongoing maintenance. As days shorten in late summer and early fall, A. andersoni can become less active and enter dormancy, so plan your fall coverage with that in mind.
Choosing Bottles or Sachets
Bottled: for existing infestations
- A concentrated dose applied directly where pests are feeding.
- Best for bringing an existing infestation under control.
- Suitable for houseplants, garden beds, greenhouses and larger growing areas.
- Reapply weekly or every other week as needed.
Slow-release sachets: for prevention and maintenance
- Each sachet holds mixed life stages and provides steady output for 2–4 weeks.
- Ideal for ongoing prevention rather than active infestations.
- Hang them once and leave them in place until it’s time to replace them.
- Keep sachets out of direct sun and away from standing water or heavy spray.
Application Rates
These are general starting points — actual application should be adjusted based on pest pressure/species, plant type, and infestation severity.
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 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
Temperature: 47°F – 104°F
Humidity: 60–90%
Application Instructions
Bottled
- Apply in the morning, in the evening, or while grow lights are off.
- Remove heavy webbing from the affected leaves.
- Lightly mist the foliage.
- Sprinkle the contents directly onto infested leaves, or use Hanging Boxes to place the predators in the canopy near pest activity.
- Leave the open container among the plants for up to 72 hours so all of the product reaches the foliage.
- Reapply weekly or every other week until pest mites are under control, then switch to sachets for maintenance.
Sachets
- Choose the plants where prevention is the goal.
- Hang one sachet per plant, or one per 3–6 sq. ft. where plants touch.
- Place it on a shaded stem, out of direct sun.
- Replace sachets every 2–4 weeks for continuous coverage.
Pairing for Heavier Mite Pressure
For stubborn spider mite infestations, combine A. andersoni with other mite predators to build layers of control:
- Phytoseiulus persimilis: a fast-acting specialist for humid hot spots.
- Stethorus punctillum: a spider mite–feeding beetle that targets dense colonies.
- Feltiella acarisuga: a flying predator whose larvae feed on spider mites, reaching colonies on upper leaves.
- Hang Good Bug Supplemental Diet Cards nearby to give A. andersoni an Artemia-based food source when pest mites and pollen are scarce.
Safe, Sustainable Pest Management
- No synthetic pesticides or spray residue
- Safe around people and pets when used as directed
- Suitable for edible crops when used as directed
- Works alongside existing IPM programs
- No protective equipment required
Storage
For best results, use the same day you receive it. If you have to wait, keep the container out of direct sun and use it within 18 hours. Do not refrigerate or freeze.
FAQs
How many A. andersoni do I need?
For bottled material, start at 2–5 mites per sq. ft. for light pest pressure. Use 5–7 per sq. ft. where pest mites are already established, and reapply weekly or every other week. For sachets, hang one per plant when plants aren’t touching, or one per 3–6 sq. ft. when they are, and replace them every 2–4 weeks. Adjust from there based on what you see on the leaves.
Should I choose bottles or sachets?
Choose bottles when pest mites are already feeding, because you can put a concentrated dose right where the problem is. Choose sachets for prevention and upkeep, since they give steady coverage for weeks without reapplying. Many growers start with bottles to bring an infestation down, then switch to sachets to keep it from coming back.
Can I use A. andersoni indoors?
Yes. It works in grow rooms, greenhouses and on houseplants as well as in outdoor gardens. Indoors, keep humidity within its 60–90% range for best results.
Can I use neem oil or insecticidal soap with A. andersoni?
Not at the same time. Both sprays can harm predatory mites on contact. If you need to spray first, let it dry completely and wait before adding A. andersoni. Avoid spraying plants where sachets are hanging.
Should I use A. andersoni or P. persimilis?
It depends on the job. A. andersoni is the better pick for preventive, season-long coverage, especially where temperatures and humidity swing. P. persimilis is a spider mite specialist that clears active infestations faster, but it needs high humidity and plenty of spider mites to keep going. Many growers use both: A. andersoni for standing protection and P. persimilis for hot spots.
What happens when the pest mites are gone?
Because A. andersoni is a generalist, it can live on pollen when prey runs low. That means it can stay in your crop and catch new pest mites as they show up. In late summer and early fall, shorter days can send it into dormancy, so plan your fall coverage around that.
Is it safe around kids, pets and food crops?
Yes, when used as directed. It’s a natural, pesticide-free option, it’s suitable for edible crops, and it doesn’t require protective equipment to apply.
When will I see a difference?
A. andersoni builds control gradually as it feeds and reproduces on your plants. It isn’t an instant knockdown. Check the undersides of leaves weekly. Fewer pest mite eggs and less new stippling are good signs it’s working. For a heavy infestation, use the higher bottled rate or pair it with P. persimilis.