Amblyseius cucumeris
Amblyseius cucumeris — now named Neoseiulus cucumeris — is the standard predatory mite for thrips: a cream to tan, pear-shaped mite 0.5–1 mm long, sold in bran or in slow-release sachets. It kills only first-stage thrips larvae, so it goes in at planting as a preventive and will not rescue a crop already full of thrips. It also eats pollen and some pest mites, does as well as the Swirski mite in short winter days at lower cost, and needs humid air.
At a glance
- Also called
- Neoseiulus cucumeris
- Size
- 0.5–1 mm; cream to tan
- Rate
- 50–100 /m²; to 350 at peak
- Temp
- 15–25 °C (Koppert; others higher); not above 30 °C
- Humidity
- Above 65–70%
- Sachets last
- 4–6 weeks (Dragonfli, Buglogical: 3–4)
How it works
The mite feeds on first-stage thrips larvae; UConn notes that second-stage larvae are already too big for it to kill, though they spend less time feeding when it is about. That is the whole logic of using it: because it only takes the youngest larvae, releases start at planting, before thrips are seen. It also eats pollen and preys on spider, broad and cyclamen mites, so it can hang on in a crop with little prey. Sachets hold bran, mould mites that feed on it and the predators that feed on them, and release mites for about four to six weeks.
It is a slow, preventive predator, not a knockdown — Cornell says not to expect quick control of a high pest population. It needs humidity: eggs shrivel and die in dry air (Dragonfli: none hatch below 60%; Koppert: sensitive below 70%), so sachets go inside the canopy, out of direct sun. Koppert gives 15–25 °C as its best range and says it stops working above 30 °C, though sources disagree: UConn gives an optimum of 75–85 °F (24–29 °C) and Cornell 25–35 °C. In UConn's summary of Canadian trials, the Swirski mite out-performed it under summer conditions, while in short winter days both worked and cucumeris is cheaper. Like the Swirski mite, it does not work on tomato.
Is it established?
What a working programme looks like. Check the sachets and the flowers, not the sticky cards alone: cards catch adults, and this mite targets young larvae, not adults.
- DAY 1Sachet contents on white paper show tan, fast predators among slower white mould mites
- WEEK 1–2Mites on leaf undersides and inside flowers, seen with a hand lens
- WEEKS 3–8Suppliers give three to eight weeks for it to establish; thrips damage on new growth should level off
- WEEKS 4–6Sachets are spent; replace them to keep predators coming
Release & handling
Use on arrival. Koppert allows 1–2 days at 10–15 °C in the dark, with ventilation so carbon dioxide does not build up; Arbico says within 18 hours and not to refrigerate. Never leave sachets in direct sun, where they overheat and dry out.
Cool, dark, ventilated
10–15 °C. Never in the fridge. Use within a day or two at most.
Turn, then sprinkle
Rotate the tube to mix the mites through the bran, then sprinkle onto the leaves or in small heaps on rockwool slabs.
Inside the canopy
Hang in shade, where it is cooler and more humid. UConn: one mini-sachet per hanging basket, one to four per shuttle tray.
Replace every 4–6 weeks
Keep the programme running while thrips can arrive. Tip an old sachet onto paper to see if it is still producing.
Pesticide sensitivity
Cornell says it can be sensitive to many neonicotinoids and pyrethroids. Check the IOBC database or the supplier's side-effects list before any spray. Check a product →
When to choose something else
A cheap, preventive thrips mite. Choose something else when:
- Thrips are already numerous or adults are the problem — Orius bugs take adults and larvae
- The house runs hot, above about 30 °C — Koppert says it stops working there, and in UConn's summary the Swirski mite out-performed it in summer
- The crop is tomato — neither mite works on tomato leaves
- The air is dry — below 60–70% relative humidity its eggs fail
- Thrips are pupating in the compost — add the soil mite Stratiolaelaps scimitus underneath
Where to buy
Suppliers listed alphabetically, not ranked. Many still sell it as Amblyseius cucumeris. helpfulbugs takes no commission and does not sell insects.
- Arbico Organics25,000 to 500,000; sachetsUS
- Buglogical50,000 / 100,000 / 250,000US
- Dragonfli (Thrip Killer)5 to 500 sachetsUK
- Koppert (Thripex, Thripex-Plus)50,000 / 100,000 / 500,000; 500 sachetsGLOBAL
Amblyseius cucumeris by target
Rate and timing differ by what you are releasing it against. Each page below is the program for one pest.