# Parasitoid

> An insect, usually a tiny wasp, whose larva develops inside or on a single host pest and kills it, often leaving a 'mummy'.

- Canonical: https://genetixbay.com/knowledge/glossary/parasitoid.html
- Also written: parasitoids
- 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"

A parasitoid is an insect whose young develop in or on one host and kill it. UC [IPM](https://genetixbay.com/knowledge/glossary/ipm.md) explains they are called parasitoids rather than parasites because they kill the host. Most used in greenhouses are small wasps, for example [Aphidius](https://genetixbay.com/knowledge/glossary/aphidius.md) on [aphids](https://genetixbay.com/knowledge/glossary/aphid.md), Encarsia and Eretmocerus on [whiteflies](https://genetixbay.com/knowledge/glossary/whitefly.md), Leptomastix and Anagyrus on [mealybugs](https://genetixbay.com/knowledge/glossary/mealybug.md) and Trichogramma on moth eggs.

## In practice

Parasitoids are often host-specific, so the species must match the pest; the wrong Aphidius for the aphid present does little. Their own development time sets how long control takes, often two to three weeks before mummies appear. Most are harmed by broad-spectrum sprays and some are caught on [sticky cards](https://genetixbay.com/knowledge/glossary/sticky-trap.md), so plan both around releases.

## Don't confuse with

- **Predator**: eats many prey, e.g. [predatory mites](https://genetixbay.com/knowledge/glossary/predatory-mite.md) and [lacewing](https://genetixbay.com/knowledge/glossary/lacewing.md) larvae.
- **Parasite**: lives on a host without necessarily killing it.

## Related terms

[Aphidius](https://genetixbay.com/knowledge/glossary/aphidius.md), [Biological control](https://genetixbay.com/knowledge/glossary/biological-control.md), [Banker plant](https://genetixbay.com/knowledge/glossary/banker-plant.md)

## Read more

- [Aphids on cannabis: species, life tables, population growth and IPM](https://genetixbay.com/knowledge/pests/aphids.md)
- [Whiteflies on cannabis: life table, temperature, parasitoids and IPM](https://genetixbay.com/knowledge/pests/whiteflies.md)
- [Mealybugs and root mealybugs on cannabis: ID, life cycle in numbers and IPM](https://genetixbay.com/knowledge/pests/mealybugs.md)

## Sources

1. UC IPM. Parasitic Wasps and Flies. https://ipm.ucanr.edu/home-and-landscape/parasitic-wasps-and-flies/