# Phytoseiulus persimilis

> 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.

- Canonical: https://genetixbay.com/knowledge/glossary/phytoseiulus-persimilis.html
- Also written: persimilis, P. persimilis, Chilean predatory mite
- Glossary category: Pests and diseases · Evidence: Established
- Status: Draft: awaiting expert review · Updated: 2026-10-31
- Licence: CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/), attribute "GenetixBay cannabis glossary"

*Phytoseiulus persimilis* is a [predatory mite](https://genetixbay.com/knowledge/glossary/predatory-mite.md) of the family Phytoseiidae that feeds almost only on [spider mites](https://genetixbay.com/knowledge/glossary/two-spotted-spider-mite.md) in the genus *Tetranychus*, including the two-spotted spider mite. Adults are bright orange-red, pear-shaped, longer-legged and faster than their prey. They eat all stages of spider mites and reproduce quickly when food is plentiful.

## In practice

Growers use *persimilis* as the knock-down predator for established spider mite patches, released directly on the stippled leaves. It works best in moderate temperatures and at [relative humidity](https://genetixbay.com/knowledge/glossary/relative-humidity.md) above about 60%; hot, [dry rooms](https://genetixbay.com/knowledge/glossary/drying-room.md) over roughly 30 °C (86 °F) hurt it. Because it is a specialist, the population crashes once spider mites are gone, so it is not a preventive choice. A common pairing is *persimilis* for hot spots plus *[Neoseiulus californicus](https://genetixbay.com/knowledge/glossary/neoseiulus-californicus.md)* across the room for staying power. Avoid broad-spectrum sprays before and after release.

## Don't confuse with

- **Neoseiulus californicus**: a pale, slower generalist that persists at low prey and tolerates heat.
- **Spider mites**: plant feeders with two dark body spots; *persimilis* is uniformly orange-red.
- **Red velvet mites**: larger soil mites, not a [biocontrol](https://genetixbay.com/knowledge/glossary/biological-control.md) product.

## Related terms

[Two-spotted spider mite](https://genetixbay.com/knowledge/glossary/two-spotted-spider-mite.md), [Neoseiulus californicus](https://genetixbay.com/knowledge/glossary/neoseiulus-californicus.md), [Predatory mite](https://genetixbay.com/knowledge/glossary/predatory-mite.md), [Biological control](https://genetixbay.com/knowledge/glossary/biological-control.md)

## Read more

- [Spider mites on cannabis: life tables, ID and IPM](https://genetixbay.com/knowledge/pests/spider-mites.md)

## Sources

1. UC IPM. Natural Enemies Gallery: Phytoseiulus predatory mites. https://ipm.ucanr.edu/natural-enemies/phytoseiulus-predatory-mites/
2. UConn IPM. Biological control of spider mites (2019 fact sheet). https://ipm.cahnr.uconn.edu/wp-content/uploads/sites/3216/2022/12/2019biologicalcontrolofspidermitesfinal2-1.pdf