# Mealybug

> Soft-bodied sap-sucking insects of the family Pseudococcidae, covered in white waxy filaments, that hide in stem joints and roots and excrete honeydew.

- Canonical: https://genetixbay.com/knowledge/glossary/mealybug.html
- Also written: mealybugs, mealy bug, Pseudococcidae, citrus mealybug, Planococcus citri, root mealybug
- 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"

Mealybugs are scale insects of the family Pseudococcidae, about 2-4 mm long, whose oval bodies are coated in white, mealy wax. They feed on sap through a stylet and excrete [honeydew](https://genetixbay.com/knowledge/glossary/honeydew.md). [Foliar](https://genetixbay.com/knowledge/glossary/foliar-feeding.md) species such as the citrus mealybug (*Planococcus citri*) cluster in leaf axils and stem joints; root mealybugs (*Rhizoecus* species) live in the root ball.

## In practice

Mealybugs are an uncommon cannabis pest and nearly always come in on houseplants or clones from a mixed collection. Look for cottony tufts in branch crotches, egg sacs, honeydew and [sooty mould](https://genetixbay.com/knowledge/glossary/sooty-mould.md). Root mealybugs show as white waxy patches on the root ball and the inside of the pot. The wax repels water-based sprays, so contact products struggle. [Biological control](https://genetixbay.com/knowledge/glossary/biological-control.md) in greenhouses uses the [mealybug destroyer](https://genetixbay.com/knowledge/glossary/ladybird.md) beetle (*Cryptolaemus montrouzieri*) and [parasitic wasps](https://genetixbay.com/knowledge/glossary/aphidius.md). Quarantine incoming plants and keep ornamentals out of the grow. Check what is registered for cannabis locally.

## Don't confuse with

- **Aphids**: no wax coat, faster breeding, cornicles on the rear.
- **Powdery mildew**: white patches on leaf surfaces that wipe off and have no insects.
- **Scale insects**: fixed under a hard or waxy shell, not mobile.

## Related terms

[Scale insect](https://genetixbay.com/knowledge/glossary/scale-insect.md), [Aphid](https://genetixbay.com/knowledge/glossary/aphid.md), [Ladybird](https://genetixbay.com/knowledge/glossary/ladybird.md), [Quarantine](https://genetixbay.com/knowledge/glossary/quarantine.md), [Root aphid](https://genetixbay.com/knowledge/glossary/root-aphid.md)

## Read more

- [Aphids on cannabis: species, life tables, population growth and IPM](https://genetixbay.com/knowledge/pests/aphids.md)

## Sources

1. Michigan State University Extension. Managing greenhouse insects. https://www.canr.msu.edu/news/managing_greenhouse_insects