Specialist · Thrips
Neoseiulus cucumeris
The budget thrips specialist. Eats the first-stage larvae before they can drop and pupate, and it is small enough to follow broad and cyclamen mites into the new growth where they hide.
$60.00
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How much, and how often
Two questions — how bad it is, and how many plants. You get a size and the dates to put it out.
How bad is it?
Pick the one that sounds like your room. If you are between two, take the higher.
How many plants?
Six-inch pots. Count a large specimen with a dense canopy as three or four.
Your size and schedule
More about this dose
The three things people ask once they have their size. Open any of them.
Am I light, moderate or heavy?
Light
- You had to go looking for it — one silvered streak on an older leaf.
- Tap a growing tip over white paper: nothing falls, or almost nothing.
- New growth is coming in clean.
- One or two plants. The rest of the shelf is fine.
Moderate
- You notice the silvering walking past, without stopping to inspect.
- The tap test drops something most times you try it.
- New growth is marked but not distorted.
- A few plants in the same area have it.
Heavy
- You saw it from across the room — silvering across whole leaves.
- The tap test drops several larvae from one growing tip.
- New growth is scarred or twisted.
- It has reached plants that were never touching.
Overshooting costs you very little — cucumeris holds on pollen when prey runs short, so a heavy dose on a light problem simply stays on as a standing guard. Under-dosing costs you the round.
Thrips are built to be underestimated:
- Damage is a record, not a reading. Silvering is scar tissue. It stays on the leaf long after the thrips that made it have gone.
- The stage this bottle targets is the one you cannot see. First-stage larvae are smaller than the adults you occasionally spot, and they are what the dose is counted against.
- It travels before it shows. Plants touching an obviously bad one are usually already carrying it.
Why more than one round?
Putting it out
- Rotate, don't shake. End over end, gently — cucumeris settle at the top or bottom in transit, and the tumble evens the mix back out.
- Target the growing tip. Thrips feed on the newest tissue, so that is where the larvae are and where the dose belongs.
- Undersides and joints. Work the leaf undersides and the crotches where branches meet the stem.
- Cups in a windy room. If you run strong fans, tip the material into small cups tucked in the foliage so the mites have time to crawl out onto the leaf.
Everything else is optional. Get these four and the release has done what it can.
A cleaner way
On a display plant, tip small piles into bio-boxes or paper cups hung in the branches instead of dusting the foliage. Same dose, nothing visible on the leaf.
The failure is forgetting. Very few programs fail because the mite underperformed. They fail in week five, when the plants look fine, the reorder does not happen, and the population holding the line ages out with nothing behind it.
A schedule is the same decision, made once. A bottle when it looks bad, then another when it looks bad again, is already a rhythm — just one you have to remember at the exact moment the plants look fine.
Change the size or the frequency, skip a box, pause or cancel from your account at any time.
Is this the right beneficial for your problem?
Five questions, in the order a grower actually asks them: what have you got, is this the answer to it, what will it eat, how does it do the killing, and will it survive your room.
Is this your pest?
Cucumeris treats three things, and all three are stages you cannot see. If none of these looks like your plant, the product you want is a different one.
Thrips rasp the leaf surface and leave silvery scarring with black frass specks, worst on the newest tissue. Broad and cyclamen mites leave nothing visible at all — you read them from new growth that comes in small, hardened and twisted.
Cucumeris takes thrips first-stage larvae — the crawlers, before they can drop to the medium and pupate — and it is small enough to follow broad and cyclamen mites into the tight new growth where they hide. It does not take adult thrips: that is Orius, and the soil stages are Sf nematodes.
Then: is cucumeris the right answer to it?
Choose this if
Choose cucumeris for a room that sits at moderate temperatures, and for treating a lot of plants at once — it is the most affordable way to put real predator numbers across a large collection. The bottle is all adults, which is the difference that matters: the ratio changes the day you open it, rather than building over the following month.
Choose something else if
Heat and dry air are the limits. Above about 80°F swirskii hunts harder, and below 50% RH cucumeris eggs may not hatch — it will still eat, but it will not build. It ignores whitefly entirely, so if whitefly is in the picture choose swirskii. And run only one loose generalist in a canopy: swirskii and limonicus prey on cucumeris juveniles.
What it kills, and what it won't
It also feeds on pollen, which is not a pest — it is how the population holds on a clean plant between outbreaks instead of starving out.
How it works
What it does to the pest, what it does on the plant, and what that leaves you looking at.
It eats the crawlers
Cucumeris is a predator — not a poison, not a repellent, nothing systemic. It walks the leaf, finds a first-stage thrips larva and feeds on it directly, which is the stage before a thrips can drop into the medium and pupate. There is no residue on the plant afterwards, and there is nothing here for a pest to become resistant to.
This one is a dose, not a colony
The bottle is adults. You are buying a spike in predator numbers on the day larvae are already on the plant, not a population that builds over a month. They will lay in a humid room, but the bottle's job is the ratio today — the sachet is the version that builds.
Pest numbers, not mites
You will rarely watch this happen. They are about half a millimetre, teardrop-shaped and almost the colour of the carrier. Judge it the way a grower does — new growth coming in clean, fewer adults on the cards week to week — rather than by how many predators you can find.
It is not a knockdown. The silvering already on a leaf is scar tissue and it stays there whatever happens next. The first thing that actually changes is the growth that comes after.
Will it work in your room?
If your room runs much above 80°F, swirskii does more for the money. And if whitefly is part of the problem, cucumeris will not touch it.
About cucumeris
A predatory mite about half a millimetre long that hunts on leaves. It has no interest in your plant and no interest in you — it eats other arthropods, and when there are none left it eats pollen until there are.
New to beneficials?
Five things that catch almost everyone the first time.
After you release it
What actually changes, how fast, and the three things this one does not reach.
How you'll know it's working
Existing damage does not heal. A leaf that was silvered stays silvered after every thrips on it is dead, because that is scar tissue and not an infestation.
So judge by three things instead: fewer live larvae when you tap a growing tip over white paper, no fresh silvering on new leaves, and falling counts on a dated blue card.
Reinspect at 7–10 days. Adult thrips still landing on cards while new growth improves means the larvae are being handled and the adults are not — that is an Orius problem, not a cucumeris failure.
Getting it to you
What is in the bottle, how it travels, and what happens if it arrives wrong.
What arrives
Adult mites in a vermiculite carrier. They are beige, fast and about half a millimetre, so the honest expectation is that you will see pale grains and nothing else. The carrier goes onto the plant with them.
You are unlikely to see movement, and that is normal at this size against a pale carrier. It is not a sign that anything is wrong.
Release on arrival. Adults in a bottle have no shelf life worth using — 55–60°F in the dark for a few hours at most, and never the freezer.
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
Open it that day. Rotate the bottle gently first, then dust a pinch onto each plant, working over the new growth and the crotches where branches meet the stem.
About the ones that don't make it
Some of them die on the way. That is why we send more than you paid for.
A predatory mite is the size of a grain of table salt. It ships in a bottle, in a van, for two days.
Roughly 15% will not survive that. We cannot prevent it, so we price it in: the number on the label gets counted out, and then the cushion goes in on top of it.
Your 1,250-mite bottle leaves here holding more than 1,250. The dead ones are already paid for.
If you can see them
Ladybugs, lacewing larvae, Orius — the minute pirate bug — and the beetles. Tip a few onto white paper and give them twenty minutes at room temperature before you judge anybody.
Cold insects are genuinely good at playing dead. The deceased have been known to get up and walk off the counter.
Still more than about one in seven not moving? Photograph them and file a report.
The photo is not us doubting you. It is how we tell a bad batch from a bad courier day from a mailbox that hit 104°F.
If you can't see them
Mites, nematodes, eggs — most of what we sell, this one included. A bottle of carrier looks the same whether it holds 1,250 live mites or none, and no photograph settles that. So we don't ask you to take one.
You file the report and our entomologist takes you through the diagnostic instead — the tap test on dark paper, where the box sat, what your room was doing, and then what the pest is doing about ten days later.
Seventy-two hours from delivery, either way, with your order number. Replacement or store credit, your pick.
What it does not reach
Three gaps this page has already named, and the beneficial that closes each one.
Orius insidiosus
Cucumeris will not touch an adult thrips. If adults keep landing on your blue cards while new growth improves, the larvae are being handled and the adults are not — and that is what Orius is for. It hunts them in the flowers where they feed and lay.
Sf Nematodes
Thrips drop off the leaf to pupate in the top inch of the medium. Cucumeris never goes there, so that generation completes underneath a working foliar release. Nematodes are what reach it.
Cucumeris sachets
This bottle is a dose, not a colony — adults, released at once, to change the ratio today. A sachet is a breeding population that keeps arriving for weeks, which is what holds the plant after the bottle's generation ages out.
Two cheap things that make the rest work harder. Blue cards give you the dated count this page keeps asking you to read. Breeder's Blend is pollen and Artemia; it keeps the population fed through the lull when prey gets scarce.
Questions
What's the difference between the bottle and the sachets?
Different tools for different situations. The bottle is a one-time treatment: you open it, release the adults, and the population does its work against an active infestation. There's no ongoing release — once deployed, that's it.
The sachet is a 30-day slow-release system with a pollen-based breeding medium. A resident predator population sustains itself on the plant regardless of whether a pest outbreak is in progress. It's the prevention tool; the bottle is the treatment.
Most growers use both in sequence: bottle to knock down an active colony, sachets to maintain coverage afterward. If you don't have an active problem and want ongoing protection, start with sachets directly.
I think I have broad mites. Will the cucumeris bottle actually work on them?
Yes — and the bottle format is particularly well suited for established broad mite colonies. Polyphagotarsonemus latus shelters in bud tissue and furled new growth where contact sprays can't reach. A high-density adult release gets cucumeris into those same microhabitats immediately, rather than waiting weeks for a sachet population to build.
Broad mites are frequently misdiagnosed — their damage mimics overwatering, calcium deficiency, or viral infection. If your plants have unexplained distorted new growth, especially in aroids, peppers, or begonias, deploy cucumeris while you investigate further. The cost of a bottle is trivial compared to losing a choice plant to an undetected colony.
For very heavy infestations, a repeat bottle release 2–3 weeks after the first can accelerate control. Follow with sachets to prevent recurrence.
How do I know which bottle size to get?
Match bottle size to the number of plants you're treating and the severity of the infestation. Smaller sizes cover a few plants or a small grow tent. Mid-size bottles handle a moderately infested collection of 10–30 plants. Larger bottles suit greenhouse bays or commercial spaces.
If you're unsure, err toward more rather than less. Releasing more predators than strictly necessary has no downside — excess adults simply disperse and decline naturally when the pest population is suppressed. Under-releasing means the pest can outpace the predators.
For large-scale or ongoing commercial needs, contact us directly for volume pricing and release schedule recommendations.
I used neem oil last week. Is it safe to release cucumeris now?
Yes — neem is a contact killer and nothing else. Once the spray has dried it leaves nothing behind that will harm cucumeris, so a week out you are well clear. Rinsing leaf surfaces first is a reasonable precaution, not a requirement.
What requires a longer wait: pyrethroids 8–12 weeks, and bifenthrin 12–15. Neonicotinoids 21 days after a foliar spray, 4 weeks after a soil drench. Organophosphates and carbamates 6 weeks. Sulfur 21 days. Where the product label says longer, the label wins.
When in doubt, spray first and time your bottle release to whichever of those applies. The pest population won't disappear in that window.
Will the mites survive in my house long-term after I release them?
They'll survive and reproduce while prey is available, then naturally decline when it isn't — that's the system working correctly. Cucumeris doesn't establish permanently without a prey population and won't become a household pest. You will not end up with a predatory mite infestation.
After a bottle release the predator population builds as they find prey and reproduce, then tails off as the pest colony collapses and the food runs out. How long that takes depends on how heavy the infestation was. Once prey is exhausted, remaining adults disperse and die off naturally. No intervention required.
Where can I buy Amblyseius cucumeris, and does it matter where I get it from?
Cucumeris is available from a handful of online biological control suppliers in the US (including us) — but source quality varies more than the listings suggest. Predatory mites are perishable. What matters is how recently the colony was produced, how it was packed for transit, and whether the supplier ships on a schedule that keeps the product viable on arrival.
At FGMN we ship Monday through Thursday only, pack with temperature-appropriate cold or heat packs, and produce in small batches so you're not receiving product that's been sitting in a warehouse. We've been working with biocontrols for 20 years — we know what arrives healthy and what doesn't.
Garden centers and big-box retailers occasionally stock cucumeris sachets, but bottle product with a meaningful count is almost exclusively available through specialist suppliers online. If you're treating an established infestation, you need the right quantity from a source that knows how to get it to you alive.
I gently applied it to the plants in the evening. When I checked them a few days later, the plants looked even worse; the pests showed absolutely no signs of dying and were reproducing at a rapid pace.
Hi Fiona, thank you so much for taking the time to leave a review, and I'm really sorry for the frustration — thrips are genuinely one of the toughest pests to tackle, and I want to share some context that should help.
One of the trickiest things about thrips is that females tuck their eggs inside plant tissue, where they're completely protected — no predator, spray, or systemic can reach them there. Those eggs take 3–5 days to hatch, which often lines up with when people first check back in after releasing predators. What looks like rapid reproduction is almost always that protected egg batch emerging from the leaves, and it's one of the most common and understandable sources of frustration with thrips biocontrol.
Cucumeris feed specifically on the first-instar larval stage, which is a narrow window in the thrips life cycle, so a full treatment typically unfolds over about 45 days as every thrips and every egg already in the plants cycles through that vulnerable stage. The single biggest thing that accelerates the timeline is adding beneficial nematodes (Steinernema feltiae) as a soil drench — they take out the pupal stage in the soil that Cucumeris can't reach, and together the two close the full life cycle.
I'd genuinely love to help you see this through. If you'd like, please email us at info@fgmnnursery.com with your order number and a bit about your setup — we'll be more than happy to help you through what you should be looking for, length of time, supportive care, and anything else that might be helpful. Thanks again for the feedback.
The customer service is impeccable! I asked many questions and their quick response on all of my questions was fantastic! I will definitely order from this company again!!
I opened the Cucumeris tube and watched them storm out ready to destroy my thrips problem!
Excellent
This container is bigger than expected and the mites did a good job managing the outbreak.
After two days of use I haven’t seen a single thrip