Amblyseius Andersoni Slow-Release Prevention Sachets

Andersoni is a polyphagous predator, meaning it eats a wide variety of pests. It is particularly valuable for controlling microscopic mites that other predators miss.

• Primary Targets: Two-Spotted Spider Mites, Hemp Russet Mites, Broad Mites, and Cyclamen Mites.
• Secondary Targets: Whitefly eggs and pollen.
• Micro-Mite Control: Because Andersoni is slightly smaller than other predators, it is excellent at hunting the tiny Russet and Broad mites that hide in plant crevices.

This is the most adaptable mite in our lineup, thriving in conditions that would stress other species.

• Temperature: Active between 43°F - 100°F. Ideally 68°F - 77°F.
• Humidity: Requires moderate humidity (above 40–50% RH). It is more forgiving of dry air than Persimilis but less drought-tolerant than Californicus.
• Food Source: Can survive on pollen and fungal spores for weeks without prey, making it ideal for preventative sachets.

Andersoni sachets are back in stock. Here is how they compare to the other slow-release options.

• Andersoni vs. californicus: Choose californicus when the room is consistently hot and dry. Choose andersoni when it swings — it holds across a 43°F to 100°F span and is not affected by day length, so it keeps working through winter indoor grows.
• Andersoni vs. swirskii: Choose swirskii for a room that runs genuinely warm and where thrips and whitefly are the worry. Andersoni is the mite specialist of the two.
• Andersoni vs. Special Blend sachets: Special Blend now contains andersoni alongside californicus, swirskii and cucumeris. Choose the blend for the widest coverage in one hanger; choose andersoni alone when mites are the known risk and you want the whole sachet working on them.

The eriophyid job. Russet and rust mites are eriophyids — a different family from spider mites, and almost nothing else preys on them. This is the sachet for that problem.

Sachets are for prevention. If you already have webbed plants or a heavy infestation, a sachet is too slow. Use loose mites in a bottle for immediate knockdown.

Our sachets are mini-breeding systems that release fresh predators over 4–6 weeks.

• Placement: Hang 1 sachet every 3–5 linear feet along crop rows, or roughly 1 per large plant. Place them in the middle-to-upper canopy where pests are most likely to travel.
• DO NOT OPEN: Never tear or cut the sachet open. The paper packet is a breeding nursery designed to release mites slowly through the pre-punched hole. If you open it, you destroy the colony and lose the slow-release benefit.
• Handling: Hold the sachet by the cardboard hook or tab. Do not squeeze the belly of the sachet, or you will crush the mites inside.
• Maintenance: Do not spray water directly onto the paper sachet, as it can drown the colony. Mist the leaves around it instead.
• Timing: Replace sachets every 4 weeks to ensure continuous protection.

Packaging: Sold in boxes of paper sachets containing a bran/vermiculite carrier and a food source (feeder mites) to sustain the colony during transit.

Viability: You will not see massive movement inside the sachet immediately, as the population breeds inside.

Storage: Hang immediately. Do not refrigerate sachets, as the condensation can ruin the paper and kill the colony. Store at 55–60°F for no more than 24 hours if necessary.

Nope! Never tear open the sachet. The sachet is a nursery. The mites breed inside and slowly crawl out of the small pinhole over the course of 4–6 weeks. If you pour them out, you lose the "slow release" benefit.

Yes — Andersoni is one of the few commercially available predators with a real record against eriophyid mites, the group that includes russet and rust mites. While it is unavailable we do not have a substitute for that job. Californicus, cucumeris and swirskii — the species in our other sachets — have all been tested against eriophyids and none of them controlled the pest, so we are not going to point you at one and let you find out. For broad mites and cyclamen mites, which are a different family altogether, cucumeris is the one with the record. Because these pests are microscopic, use any of them preventatively or at the very first sign of damage.

Yes. Because they tolerate cooler temperatures and temperature fluctuations, Andersoni is excellent for outdoor gardens, fruit trees, and vineyards. Hang the sachets on branches where they are shaded from direct, scorching noon sun.

It is hard to see with the naked eye. If you look closely at the exit hole with a macro lens or loupe, you should see tiny mites exiting periodically. The best sign of success is a lack of pest damage on your new growth.

Yes, and that pairing still works with what is in stock. Use Persimilis to "put out the fire" (knock down active spider mites) and hang Special Blend sachets to "fireproof the building" (prevent them from coming back).

Californicus, because Andersoni is not available. It used to come down to temperature and pest type: colder nights or russet mites pointed to Andersoni, a hot dry room with spider mites pointed to Californicus. Californicus is now the closest single species we stock. For russet or rust mites specifically there is no substitute in stock — the Special Blend does not cover them either. If thrips are part of the picture, use the Special Blend.