# Beauveria bassiana

> An insect-killing fungus whose spores germinate on contact, penetrate the cuticle and kill soft-bodied pests such as whiteflies, thrips, aphids and root aphids.

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- Also written: Beauveria, B. bassiana, white muscardine fungus, entomopathogenic fungus
- 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"

*Beauveria bassiana* is an entomopathogenic fungus: it infects and kills insects. Spores that land on an insect [germinate](https://genetixbay.com/knowledge/glossary/germination.md), grow through the cuticle and multiply inside the body. Dead insects turn stiff and become covered in white fungal growth, which is why the disease is called white muscardine. It is found naturally in soils worldwide.

## In practice

Growers apply spore formulations as [foliar sprays](https://genetixbay.com/knowledge/glossary/foliar-feeding.md) against [whiteflies](https://genetixbay.com/knowledge/glossary/whitefly.md), thrips and [aphids](https://genetixbay.com/knowledge/glossary/aphid.md), or as drenches against [root aphids](https://genetixbay.com/knowledge/glossary/root-aphid.md) and other soil pests. Spores need direct contact with the pest and benefit from high humidity for the first hours after application; very dry air and some fungicides reduce [efficacy](https://genetixbay.com/knowledge/glossary/photon-efficacy.md). It works over days, not hours, so it is used early and repeated. Because it adds live fungal spores, growers generally keep it off flowering buds, where it could raise microbial counts on lab tests. Check what is registered for cannabis locally and what the label allows by growth stage.

## Don't confuse with

- **Botrytis**: a plant pathogen that rots buds; *Beauveria* attacks insects, not plants.
- **Bacillus thuringiensis**: a bacterium that must be eaten.
- **Metarhizium**: a related insect-killing fungus with green spores.

## Related terms

[Whitefly](https://genetixbay.com/knowledge/glossary/whitefly.md), [Thrips](https://genetixbay.com/knowledge/glossary/thrips.md), [Root aphid](https://genetixbay.com/knowledge/glossary/root-aphid.md), [Biological control](https://genetixbay.com/knowledge/glossary/biological-control.md), [Contact vs systemic](https://genetixbay.com/knowledge/glossary/contact-vs-systemic.md)

## Read more

- [Whiteflies on cannabis: life table, temperature, parasitoids and IPM](https://genetixbay.com/knowledge/pests/whiteflies.md)
- [Root aphids (rice root aphid) on indoor cannabis: ID, life cycle in numbers and IPM](https://genetixbay.com/knowledge/pests/root-aphids.md)

## Sources

1. UConn IPM. Biological Control of Whiteflies. https://ipm.cahnr.uconn.edu/ipm-biological-control-of-whiteflies
2. Cranshaw, W. and Wainwright-Evans, S., 2020. Cannabis sativa as a host of rice root aphid (Hemiptera: Aphididae) in North America. Journal of Integrated Pest Management 11(1):15.