Our Top Andersoni for Spider Mite Control
Andersoni for Spider Mite Control
Wide-temperature predator of spider, russet, and broad mites — Amblyseius andersoni.
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What it targets
Amblyseius andersoni is a generalist phytoseiid that eats a wider span of mite prey than most specialists growers reach for. The vendor lists two-spotted spider mite (Tetranychus urticae), carmine mite (T. cinnabarinus), Lewis mite (Eotetranychus lewisi), Banks grass mite (Oligonychus pratensis), broad mite (Polyphagotarsonemus latus), the eriophyid russet/gall/rust mites, European and citrus red mite (Panonychus spp.), and young thrips larvae as accepted prey. It is reported as a predator of twospotted spider mites on heavily infested apple, peach, grape, and raspberry plantings, and as one of the first phytoseiids to recolonize orchards after acaricide programs wind down.
Use it as a preventive in fruit, ornamentals, hemp, and tree nurseries before mite pressure builds, and pair it with Neoseiulus californicus or Phytoseiulus persimilis when an outbreak is already underway and you need direct knock-down. Andersoni's flexibility — it can hold on pollen, honeydew, and fungi when prey is sparse — is what lets it stay resident in a crop weeks ahead of the first hot spot.
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How it works
Every mobile stage of Amblyseius andersoni — larva, two nymphal instars, adult — is predatory. They feed on eggs, juveniles, and adults of spider mites, and they will also take young thrips larvae, flower pollen, sugary excretions, and fungi. That alternate diet matters in practice: andersoni can be released into a flowering crop before prey is established and still hold a population while it waits.
The active temperature window is wide — 43°F to 104°F — which is why the species shows up in field, orchard, and indoor releases where temperature swings would stall Phytoseiulus persimilis. Adults live about three weeks, and a female lays 25–30 eggs over her lifetime. Egg-to-adult timing runs roughly 8–12 days in summer conditions. As day length shortens in early autumn, andersoni enters diapause and overwinters in the crop, becoming active again as early as January when temperature and prey allow.
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Crops, environments, and climate
Crops it supports
Soft fruits
Ornamental crops
Hemp / Cannabis
Tree nurseries
Environments
Greenhouses
Indoor facilities
Fields & orchards
Gardens
04
Storage
Keep out of direct sunlight. The product can be held at 50–60°F, but the vendor's working guidance is to release within 18 hours of receipt — live phytoseiids don't tolerate cold-chain layovers the way diapausing material does.
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Instructions of use
Mini sachets with hooks
Hang from plant branches, plant wires, or trellises. Keep them off heating pipes. Sachets handle short moisture exposure, but don't let the bottom touch a wet surface — wicking will kill the breeding population inside. A single sachet keeps producing predatory mites for four to five weeks; mark the deployment date so you know when to swap them.
Shaker tube (loose carrier)
Shake small quantities onto the crop near the flowers, where pollen and protected microhabitat are densest. You can also load Universal Release Boxes (URBs) — strategic placement points that mimic sachet behavior without carrier dust on the leaves. Use no more than about a third of a box per station, and hang where pressure is starting to build.
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Monitoring & advisories
Monitor for
- Stippling, webbing, or pale new growth — the earliest signs of spider-mite pressure.
- Empty webbing under leaves: a good sign predators are clearing pockets that were active a week ago.
- Fast-moving mites on the underside of leaves — most phytoseiids run, while spider mites stay put feeding.
- Falling pest counts after the release. Phytoseiids hide in foliage and ambush prey, so direct scouting of the predator itself is unreliable.
Advisories
- Release while mite numbers are low. Andersoni is built for prevention — it knocks down small colonies before they explode, not large infestations after the fact.
- Keep sachets out of direct sunlight for any extended period — heat inside the sachet kills the breeders.
- Pair with a specialist (P. persimilis for hot, webbing-heavy hot spots; N. californicus for moderate, lingering pressure) when an outbreak is already underway.
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Release rates — for conventional crops
| Scenario | Format | Rate & interval |
|---|---|---|
| Preventive routine | Shaker tube | 1–5 mites per 100 sq. ft., weekly |
| Hot spots step up | Shaker tube | 5–25 mites per 100 sq. ft., weekly |
| Sachet program slow-release | Mini sachets with hooks | 1 sachet per 6–10 sq. ft. of canopy |
| Trees orchard | Mini sachets with hooks | 1 sachet per tree |
| Rates above are vendor-published conventional guidance. Adjust for crop susceptibility, season, and the trend in your scouting counts. | ||
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Cannabis Alert
Conventional release rates are usually not sufficient for cannabis growers. We recommend you double the rate or contact us for personalized help.
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Life cycle
Andersoni runs egg → larva → protonymph → deutonymph → adult. Juvenile development typically wraps within 12 days of emergence; adults then live about three weeks and lay 25–30 eggs apiece.
1
Egg
2
Larva
3
Nymph (×2)
4
Adult
Disclosures
Live-product policy. Beneficial Insectary works to guarantee live delivery of fresh organisms. Replacements or credits are offered for compromised shipments when issues are reported within 24 hours of receipt — and before any organisms suspected of viability issues are released. Don't discard the product; you may be asked to return the shipment for analysis.
Establishment of biocontrol agents. Many variables — pesticide applications, watering practices, storage, cultural and physical controls — affect BCA and pest populations across crops. Some agents need a steady pest food source, others need alternate food (pollen, nectar), others have specific photoperiod requirements. Because of these variables, long- or short-term establishment of BCAs cannot be guaranteed after release, and refunds, discounts, or credits are not offered on products that have already been released.