# Entomopathogenic fungi

> Fungi that infect and kill insects and mites through the cuticle; their spores need high humidity at the leaf surface to germinate.

- Canonical: https://genetixbay.com/knowledge/glossary/entomopathogenic-fungi.html
- Also written: insect-killing fungi, mycoinsecticide, fungal biopesticide, Metarhizium, Isaria fumosorosea, Lecanicillium
- 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"

Entomopathogenic fungi are fungi whose spores land on an insect or mite, [germinate](https://genetixbay.com/knowledge/glossary/germination.md), penetrate the cuticle and kill it from inside within days. [Beauveria bassiana](https://genetixbay.com/knowledge/glossary/beauveria-bassiana.md), Metarhizium species, Cordyceps (Isaria) fumosorosea and Lecanicillium are the main greenhouse examples, and extension [biocontrol](https://genetixbay.com/knowledge/glossary/biological-control.md) guides for [whiteflies](https://genetixbay.com/knowledge/glossary/whitefly.md) list several of them.

## In practice

Spores need moisture to germinate, so these products work best when leaf-surface humidity stays high for hours, which conflicts with flower rooms kept at 40-55% [RH](https://genetixbay.com/knowledge/glossary/relative-humidity.md) to prevent [bud rot](https://genetixbay.com/knowledge/glossary/botrytis.md). They are mainly a veg-stage and media-drench tool. Many fungicides kill them, so do not tank-mix. Follow the label and local law.

## Don't confuse with

- **Plant pathogens**: fungi that attack the crop, such as botrytis.
- **Bt**: a bacterium, not a fungus, that works only when eaten.

## Related terms

[Beauveria bassiana](https://genetixbay.com/knowledge/glossary/beauveria-bassiana.md), [Biological control](https://genetixbay.com/knowledge/glossary/biological-control.md), [IPM](https://genetixbay.com/knowledge/glossary/ipm.md)

## Read more

- [Temperature, humidity and pest population growth in cannabis: every major pest compared](https://genetixbay.com/knowledge/pests/temperature-humidity-and-pest-population-growth.md)
- [Thrips on cannabis: life table, temperature, scouting and biological control](https://genetixbay.com/knowledge/pests/thrips.md)
- [Whiteflies on cannabis: life table, temperature, parasitoids and IPM](https://genetixbay.com/knowledge/pests/whiteflies.md)

## Sources

1. UConn IPM. Biological Control of Whiteflies. https://ipm.cahnr.uconn.edu/ipm-biological-control-of-whiteflies