# Root aphid

> Aphids that colonise roots and the crown below the medium surface, on cannabis chiefly the rice root aphid (Rhopalosiphum rufiabdominale), causing slow, unexplained decline.

- Canonical: https://genetixbay.com/knowledge/glossary/root-aphid.html
- Also written: root aphids, rice root aphid, Rhopalosiphum rufiabdominale, RRA
- 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"

Root aphids are [aphids](https://genetixbay.com/knowledge/glossary/aphid.md) that feed on roots instead of foliage. On indoor cannabis the main species is the rice root aphid (*Rhopalosiphum rufiabdominale*), first documented on North American cannabis in 2020. They are olive to dark green, about 1-2 mm long, and often coated with a fine white wax on the roots.

## In practice

Root aphids are hard to spot because they live out of sight. Symptoms look like a feeding or watering problem: slow growth, yellowing, wilting between waterings and poor response to feed. Growers find them by tipping a plant out of its pot and inspecting roots and the root ball edge, or by seeing winged adults on [yellow sticky traps](https://genetixbay.com/knowledge/glossary/sticky-trap.md), often mistaken for [fungus gnats](https://genetixbay.com/knowledge/glossary/fungus-gnat.md). They move between rooms on clones and in reused media. Management combines quarantine, fresh media between runs, and root-zone biologicals such as [entomopathogenic fungi](https://genetixbay.com/knowledge/glossary/entomopathogenic-fungi.md) and soil predators. Check what is registered for cannabis locally.

## Don't confuse with

- **Fungus gnat**: flies with dangling legs; larvae are clear-bodied maggots, not aphids.
- **Root mealybugs**: white, cottony, slow-moving and lacking cornicles.
- **Root rot**: brown, slimy roots with no insects.

## Related terms

[Aphid](https://genetixbay.com/knowledge/glossary/aphid.md), [Fungus gnat](https://genetixbay.com/knowledge/glossary/fungus-gnat.md), [Steinernema feltiae](https://genetixbay.com/knowledge/glossary/steinernema-feltiae.md), [Beauveria bassiana](https://genetixbay.com/knowledge/glossary/beauveria-bassiana.md), [Quarantine](https://genetixbay.com/knowledge/glossary/quarantine.md)

## Read more

- [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. 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.
2. Utah State University Extension. Rice Root Aphids (hemp). https://extension.usu.edu/planthealth/ipm/notes_ag/hemp-rice-root-aphid