Amblyseius andersoni Sachets for Mite Prevention
Andersoni predatory mite · Amblyseius andersoni
4.6 · 9 reviewsSlow-release paper sachets, each holding a breeding colony of Amblyseius andersoni predatory mites that walk out onto the plant over four to six weeks. Hung one every three to five linear feet, they guard against spider, broad, cyclamen and russet mites, especially in rooms where the temperature swings. They're prevention, not a rescue for an infestation already under way.
- Conditions
- 43–100°F, Above 40–50% RH
- Good to know
- Nothing to see at the sachet. It looks identical the whole time. The mites trickle out through the vent day after day, so leave it closed. What to expect
When to choose something else
Not for adult thrips, anything in the soil.
Shipping details
Shipping
| Est. ships | Est. arrives | |
|---|---|---|
| Standard | ||
| Overnight |
Raising a fresh batch for you? Add up to 7 days to both dates.
Estimates. Overnight speeds up the trip, not the packing: its one day on the truck starts once it ships.
- Monday to Thursday only. Nobody spends the weekend in a warehouse.
- Check your address at checkout. Bugs are brilliant at finding aphids and hopeless at finding a new front door.
Ordering with friends? Get group pricing
Everyone picks their own. It ships to you in one box.
Buying for a greenhouse, farm or shop? Ask about wholesale
Right for you?
Your pest, your growing space, how many you need
What it prevents
Prevention. Put it out on clean plants, before broad mites show up.
| Pest | Treats or prevents | Why |
|---|---|---|
| Broad mites | Prevents | Put out on clean plants, it's already there when they arrive, so they have a harder time building up. |
Start with a treatment instead:
Not for adult thrips, anything in the soil.
Or choose instead
When one of these fits your situation better than amblyseius andersoni slow-release prevention sachets.
-
Choose this instead
Amblyseius andersoni
If there is already webbing.
from $57
-
Choose this instead
Neoseiulus californicus Slow-Release Prevention Sachets
If the room is hot and dry.
$3.75
-
Choose this instead
Special Blend Slow-Release Prevention Sachets
If you want the widest cover.
$5
Conditions for releasing amblyseius andersoni slow-release prevention sachets
Amblyseius andersoni slow-release prevention sachets work best when the growing space stays 43–100°F, Above 40–50% RH. These are preferred conditions, not hard limits.
Best temperature43–100°F
That bar is not a mistake. Ideally 68–77°F, but it stays on shift across nearly the whole range — which is the entire argument for this species over a specialist.
Best humidityAbove 40–50% RH
More forgiving of dry air than persimilis, less drought-tolerant than californicus. Middle of the road, and unfussy about it.
CoverageOne per 3–5 linear feet
Size by the length of the shelf, row or bench, not the number of plants. A large plant can have one of its own. Two or three on a big specimen, hung at different heights.
Sachet life4–6 weeks
Then replace it. An empty sachet is paper, and the plant is unguarded from that point on.
RefrigerateBest not
They do best kept out of a kitchen fridge, where the air is too dry. If you need to wait, they're best kept cool, dark and not bone dry at 55–60°F — but they would always rather be hanging on a plant.
Releasing
What to do, and what you'll see
What to expect
- Nothing to see at the sachet. It looks identical the whole time. The mites trickle out through the vent day after day, so leave it closed.
- They settle in and wait. On a clean plant they live on pollen and patrol the tight new growth, through cold nights and warm afternoons.
- Uneventful growth is the win. New leaves open flat and full size, with no stippling or bronze. Swap the sachet at four to six weeks so the shield stays up.
The mites you can see are most likely feeder mites
Each sachet holds feeder mites alongside your predatory mites. They're food that keeps the colony breeding. Feeder mites are quite a bit bigger than predatory mites and much easier to see, so any mites you notice on or around the sachet, moving or still, are most likely feeder mites, not your predators.
Your predatory mites are far harder to spot, and that's normal. Fewer pests and clean new growth are how you know they're working.
How to release amblyseius andersoni slow-release prevention sachets
When to put out more
Each one works for a set time, then it's spent. A fresh one keeps the guard up.
Go by the calendar, not the plant: swap it on time, even when everything looks clean.
Put it on a schedule and the next sachet arrives on its own, 10% off the first and 50% off every one after. If it turns out you don't need it, pause or cancel anytime from your account.
Reviews
What growers say
What people say
4.6 out of 5, from 9 reviews.
Such an easy way to prevent pests! I am very impressed.
Shipping was very fast and packets were very effective.
Product didn’t work but this is more about the customer service. “With all due respect” Mia, figure it out.
And to the person saying my infestation was too much for the knock out. I culled 3 plants with any webbing and only treated six that had no visible signs. I also cleaned the tent and always clean my tools. Your product didn’t work. Mia has my complete response.
This customer expressed his displeasure that this review was removed. It was initially hidden by our review team because of the attack on an employee. I am posting it in hopes that perhaps he will read the review reply. There is no crossover between the team that manages the reviews, and the customer service team. The review team actually has no access to personal information or the orders. What that means is that when you reach out to the customer service team, they’re finding out about your challenges for the first time then. Mia was trying to understand what your complaint was as well as gather your order number so that she could help you. If you would like to provide us with your order number or your name, we would be able to find it or at least narrow it down.
These were on a hibiscus tree when we bought it last year and keep all pests away the whole summer. Worked great!
Happy with my sachets!
came on time as promised. They seem effective for sure. Thanks
You can see the little mite mites crawling around if the light is bright and you wear strong readers! They crawl all over and there has been no sign of spider mites on my little lime tree or its neighbors since
product arrived just as stated. The pre delivery instructions were point on.
Excited to have them! Thank you! Need more 😂
lol Already? Let us know how we can help. Appreciate you!!
Pairs well with
Small things that help them work
-
Add alongside
Horiver Professional Sticky Traps
Most pest problems are found on a card a week or two before they are found on a leaf.
from $11
-
Add alongside
Breeder’s Blend
Keeps the population fed through the lull when prey gets scarce.
from $10
-
Add alongside
Root Network
For the roots: mycorrhizae and microbes that help roots take up water and nutrients. Use at repotting, then a monthly drench.
from $15
More to know
Ways to buy, questions and reading
Ways to buy
Once, on a schedule, with friends, or mixed with other predators.
- One time
- A single sachet, this once. Free shipping on orders of $30 or more, $15 under that.
- On a schedule
- 10% off your first box, 50% off every box after. Skip, move, pause or cancel from your account.
- Group order
- Friends each pick what they want, and it ships to you in one box.
- Mix and match
- Buy several predators together and they get cheaper.
For the curious
Everything else we know about them. Tap a topic to open it.
Is this your pest?
This is the sachet for mites, and particularly for the microscopic ones few other predators take on.
Two-spotted spider mites leave fine pale stippling that spreads across a leaf, and webbing once it is serious. Broad and cyclamen mites leave nothing visible at all — you read them from new growth that comes in small, hardened, cupped and twisted while the older leaves look perfectly fine. Russet and rust mites are the same story: the damage is all you get.
Andersoni is polyphagous, which is a long word for unfussy, and it hunts in the tight crevices of new growth where broad and russet mites hide. Whitefly eggs and pollen round out the diet.
Then: is an andersoni sachet the right answer to it?
Choose this if
Choose andersoni when the room swings. It holds across a 43 to 100°F span — wider than any other predatory mite we carry — and it is not affected by day length, so it keeps working through a winter indoor grow and through a garage where the night is cold and the afternoon is hot. It is also the eriophyid answer: russet and rust mites are a different family from spider mites and few predators take them on, and this is the one we reach for. It survives on pollen and fungal spores for weeks without prey, which is what makes a preventative sachet worth hanging on a clean plant.
Choose something else if
If the room is consistently hot and dry, californicus is the more comfortable specialist. If thrips and whitefly are the worry rather than mites, swirskii is the better generalist. And if you already have webbed plants or a heavy infestation, a sachet is too slow — that wants loose mites in a bottle for immediate knockdown.
What it kills, and what it won't
The eriophyid job is the one worth spelling out. Russet and rust mites are a different family from spider mites, and few predators in biological control take them on. If that is what you have, this is the sachet.
How a sachet works
What is actually inside it, how the mites get out, and what that buys you over a bottle.
A breeding colony, not packaging
The sachet is a nursery. Inside is a bran medium, a founding population of predators and a food source that keeps them laying for weeks. It is not a bag of mites waiting to be tipped out, which is why the one instruction that matters is do not open it.
Through a vent already built in
Every sachet has an exit hole in the seam. The mites leave through it at their own pace, a few at a time, day after day. That trickle is the whole point: a bottle gives you one wave and a sachet gives you a standing population.
A clean leaf, and nothing else
Because the mites walk out and the medium stays in the paper, there is no bran or vermiculite left on your foliage or in your flowers. If you have ever picked carrier out of a leaf sheath, that difference is worth something on its own.
Prevention, not rescue. A sachet releases over weeks, which is exactly the wrong speed for an infestation that is already running. Bottles are the knockdown; sachets are what holds the line afterwards.
About andersoni sachets
The all-weather generalist. Andersoni works across a wider span of conditions than any other predatory mite we carry, and when the room swings and the specialists stall, this is the one still on shift.
New to sachets?
Five things that catch almost everyone the first time.
What arrives
Sachets of paper, each one a live breeding colony on a bran medium with a food source sealed in beside it.
Nothing about the outside tells you anything. There is no window, no movement to look for, and no test you can run — the mites are half a millimeter and they are inside.
Hang them the day they arrive. These are living colonies rather than shelf stock, and every day in the box is a day off the release window you paid for.
When it ships, and when it lands
Shipping
We ship when they're ready to travel. Live orders go out Monday to Thursday. If a colony needs a beat to peak, or we're propagating a fresh batch, yours might hold up to a week. All mites and insects ship 2-day or Overnight depending on what's best for them.
When it lands
Unpack and hang the same day. One every three to five linear feet. On a stem in the middle of the foliage, in shade, above the soil line — not in a hot spot of direct light, and not where watering will soak it. Then leave it alone for four to six weeks.
Why we pack extra
Two days in a van is a long trip for something this small, so we send more than you paid for.
A predatory mite is the size of a grain of table salt, and a sachet is a breeding colony in a paper packet, in a van, for two days.
A trip like that is hard on anything this small, so we price it in: the founding population gets counted out, and then roughly 15% more goes in on top as a cushion.
Your sachet leaves here holding more than the label says — and unlike a bottle, the mites in a sachet keep breeding, so the number that matters is the one a week from now.
If you can see them
Ladybugs, lacewing larvae, Orius — the minute pirate bug — and the beetles. These are the ones big enough to see.
Cold insects are very good at sitting still. That's normal. Release them as this page says, and watch the pest instead.
Something look wrong? Email info@fgmnnursery.com with your order number.
If you can't see them
Mites, nematodes, eggs — and sachets more than any of them. A sealed paper packet looks the same from the outside the whole time it is working, so there is nothing for you to check or photograph.
Email info@fgmnnursery.com and our entomologist takes you through the diagnostic instead — where the box sat, what your room was doing, whether the paper arrived damp, and then what the pest is doing about ten days later.
Please do not open a sachet to check. Opening it ends the colony, and we cannot replace it afterwards.
Seventy-two hours from delivery, either way, with your order number. Replacement or store credit, your pick.
Questions about amblyseius andersoni slow-release prevention sachets
Will I have bugs flying around my house?
No. They stay on the plants, where their food is.
Do I need to open the sachet?
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.
Will they eat Russet Mites?
Yes — andersoni feeds on eriophyid mites, the group that includes russet and rust mites, which is why it's the sachet we reach for there. Research on hemp russet mite in particular is still young, so hang it early, before damage builds, rather than waiting for a problem. 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.
Can I use them outdoors?
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. Rain is fine — the paper sheds it and the colony carries on. What to avoid is standing water: do not let a sachet sit where run-off collects or where an irrigation head hits it directly.
How do I know if the sachet is working?
They're hard to see with the naked eye, and you don't need to see them. The best sign it's working is the pest: fewer of them week on week, and no new damage on fresh growth.
Can I use these with Persimilis?
Yes. Use persimilis to "put out the fire" (knock down active spider mites) and hang andersoni sachets to "fireproof the building" (help keep them from coming back).
Andersoni or Californicus?
It comes down to temperature and pest type. Colder nights, a room that will not sit still, or russet mites point to Andersoni. A hot, dry room with spider mites points to Californicus. For russet or rust mites specifically, Andersoni is the one with the record. If thrips are part of the picture, use the Special Blend.
Can I hang sachets after spraying?
It depends on what you sprayed, because there's no single waiting period for every spray. Neem and horticultural oil are safe once dry; insecticidal soap needs a day; sulfur needs 21 days; slower-breaking synthetic sprays such as pyrethroids need weeks longer. If the label says longer, the label wins. Not sure what you used? Email info@fgmnnursery.com with the product name and we'll tell you when to hang them.
How many sachets do I need?
Sachets are sized by length, not by plant count:
- Measure the shelf, bench or row. Hang one sachet every 3 to 5 linear feet. A large plant can have one of its own, and a big specimen can take two or three at different heights.
- Adjust for risk. If mites have hit this space before, use the closer spacing (one every 3 feet); for a lower-risk spot, one every 5 feet.
- It's prevention. If you already have webbing or a heavy infestation, sachets alone are too slow: release andersoni bottles first and hang the sachets behind them.
- Replace on a schedule. Each sachet releases for 4 to 6 weeks. Check the new growth at about 4 weeks and keep replacing every 4 to 6 weeks while the season is active.
Keep reading
Field Notes from the FGMN Nursery team.
No Webbing. No Warning. No Fun.
Broad mites are microscopic pest mites that cause twisted, bronzed new growth on peppers, cannabis, hoyas, and dozens…
What’s Really Inside a Predatory Mite Sachet?
Predatory mite sachets may look empty at first glance, but inside is a carefully balanced ecosystem of carrier…
Four Mites Apply for the Thrips Job
Compare cucumeris, swirskii, limonicus, and andersoni by the job they need to do on your plants—not just how…
Sources
Published guidance from university extension services. The release tips on this page also draw on what we see shipping these every week.