Field Notes
Stratiolaelaps scimitus
The beneficial
Species
Stratiolaelaps scimitus (formerly Hypoaspis miles)
Common name
Soil-dwelling predatory mite
Type
Predatory mite — generalist predator of soft-bodied pests in soil and substrate
Size
Very small. Tan-colored specks, fast-moving; to see them, tip a little carrier onto white paper and use a magnifier
How it works
Patrols the top inch of the media, eating fungus gnat larvae and thrips pupae. In reptile enclosures it attacks snake mites in the bedding where they breed, breaking the life cycle
What it eats
Hunts
Snake mites (Ophionyssus natricis), fungus gnat larvae (Bradysia spp.) and thrips pupae
Best against
Preventing fungus gnats in plants, and snake mites in reptile enclosures
Also eats
Springtails, root aphids, bulb mites, poultry mites
Eats opportunistically
Debris, algae and other soil organisms — it will hold for weeks with no pest present at all, which is why it suits bioactive setups
Won't touch
Pests on foliage. This is a ground predator — carrier dusted on leaves is carrier wasted
What arrives
Format
Bottle or tube of loose mites through a carrier medium
Ships as
Loose mites — a mix of adults, nymphs and eggs
Where it works
Optimal temp
Active between 59°F and 86°F
Humidity
Slightly humid substrate. Not bone-dry, not saturated
Establishes
Yes in bioactive terrariums and permanent beds with organic soil, where they can breed and persist for months or years. In potted plants with sterile soil they may die out once the pests are gone
Running it
Deploy
On arrival — loose mites are not a product you can hold for a week. Moisten the substrate, then rotate and tumble the container for 20–30 seconds to mix the mites through the carrier
Placement
Onto the soil or substrate surface, roughly 1 tsp per plant at the stem base; for reptiles, poured over the substrate or bedding. Top-dress, do not water in. Leave the carrier in place. They need a substrate to burrow in — on paper towels or bare glass they dehydrate
Replace
Where they cannot establish — potted plants in sterile soil, temporary setups — re-apply every 6–8 weeks for prevention
Refrigerate
No. If you must hold them, store horizontally in a cool dark place at 50–60°F for up to 24 hours
Compatible with
Beneficial nematodes — nematodes work the larvae deeper in the pot while scimitus works the surface, and they do not interfere with each other. Generally compatible with Bacillus thuringiensis (Mosquito Bits/Dunks) if applied carefully
Keep separate from
Diatomaceous earth — a mechanical killer that slices beneficial mites as readily as pests. Rove beetles (Dalotia) are a trade-off: they compete with and eat scimitus to a degree, though commercial programs run both anyway
Chemical interval
Pesticide residues run longer than most people expect. Permethrin, a pyrethroid: 8–12 weeks. Imidacloprid, a neonicotinoid: 21 days after a foliar spray, 4 weeks after a soil drench
Safe around
Humans, cats, dogs, plants, and all reptiles and amphibians
