# Honeydew

> The sugary liquid excreted by sap-feeding insects such as aphids, whiteflies, mealybugs and soft scales; it makes leaves sticky and feeds sooty mould.

- Canonical: https://genetixbay.com/knowledge/glossary/honeydew.html
- Also written: honey dew
- 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"

Honeydew is the excess sugary sap that phloem-feeding insects excrete. UC [IPM](https://genetixbay.com/knowledge/glossary/ipm.md) lists [aphids](https://genetixbay.com/knowledge/glossary/aphid.md), [leafhoppers](https://genetixbay.com/knowledge/glossary/leafhopper.md), [mealybugs](https://genetixbay.com/knowledge/glossary/mealybug.md), soft scales and [whiteflies](https://genetixbay.com/knowledge/glossary/whitefly.md) as common producers, with both immatures and adults producing it. On cannabis it shows as shiny, sticky leaf [tops](https://genetixbay.com/knowledge/glossary/top-shelf.md) beneath a colony.

## In practice

Honeydew is a diagnostic clue: sticky leaves point to a sap feeder above, not to a mite. It grows black [sooty mould](https://genetixbay.com/knowledge/glossary/sooty-mould.md) that cuts light, and ants that farm honeydew defend aphids and mealybugs from their [natural enemies](https://genetixbay.com/knowledge/glossary/biological-control.md). Washing it off treats the symptom; the colony is the problem.

## Don't confuse with

- **Sticky (slang)**: resinous buds, nothing to do with pests.
- **Guttation droplets**: water from leaf margins, not sugar.

## Related terms

[Aphid](https://genetixbay.com/knowledge/glossary/aphid.md), [Whitefly](https://genetixbay.com/knowledge/glossary/whitefly.md), [Mealybug](https://genetixbay.com/knowledge/glossary/mealybug.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. Sooty Mold. https://ipm.ucanr.edu/home-and-landscape/sooty-mold/