A predatory mite is a mite that hunts other small arthropods instead of feeding on plants. Most species used on crops belong to the family Phytoseiidae and live on foliage; Stratiolaelaps scimitus (family Laelapidae) works in the growing medium. They are bred commercially and shipped as loose material in a carrier such as bran or vermiculite, or in slow-release sachets hung on plants.
In practice
The species has to match the pest and the room. Phytoseiulus persimilis is a specialist spider mite eater; Neoseiulus californicus tolerates heat and low prey; Amblyseius swirskii targets thrips larvae, whitefly and broad mites in warm rooms; Neoseiulus cucumeris covers thrips larvae in cooler rooms. Releases work best early, while pests are scarce, and they fail when growers spray incompatible products in the same window. Check temperature and humidity ranges for each species, since many slow down below about 50% RHbeing reviewed.
Don't confuse with
- Spider mites: pests; predatory mites are faster, pear-shaped and usually lack the two dark spots.
- Parasitic wasps: insects that lay eggs inside pests rather than eating them.
- Nematodes: microscopic worms, applied as a drench.
A soil-dwelling predatory mite, formerly sold as Hypoaspis miles, that hunts fungus gnat larvae, thrips pupae and other small arthropods in the growing medium.A specialist predatory mite that eats almost only Tetranychus spider mites, eggs to adults; fast-acting on hot spots but starves once prey runs out.Tetranychus urticae, the commonest cannabis mite indoors: a 0.5 mm sap-feeder that stipples leaves pale and spins webbing, breeding fastest in hot, dry rooms.A generalist-leaning predatory mite that eats spider mites and broad mites, survives on low prey or pollen, and tolerates warmer, drier rooms than Phytoseiulus.A warmth-loving generalist predatory mite that eats thrips larvae, whitefly eggs and nymphs and broad mites, and can persist on pollen.A predatory mite that eats first-stage thrips larvae and some broad and cyclamen mites; tolerant of cooler rooms and widely used in sachets as a preventive.Relative humidity is the water vapour in air as a percentage of what it could hold at that temperature, so the same RH dries plants differently at different temperatures.Tiny parasitic wasps of the genus Aphidius that lay eggs inside aphids; the larva kills the host from inside, leaving a swollen tan mummy.Using living natural enemies, such as predators, parasitoids, nematodes and microbes, to suppress pests and diseases instead of, or before, chemical sprays.
