# Hemp russet mite

> Aculops cannabicola, a microscopic eriophyid mite specific to cannabis that causes upward leaf curl, bronzing and dull, greasy-looking trichomes.

- Canonical: https://genetixbay.com/knowledge/glossary/hemp-russet-mite.html
- Also written: russet mite, russet mites, Aculops cannabicola, HRM, rust mite
- 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"

The hemp russet mite (*Aculops cannabicola*) is an [eriophyid mite](https://genetixbay.com/knowledge/glossary/eriophyid-mite.md) about 0.2 mm long, carrot-shaped, with only four legs near the head. It feeds only on cannabis and hops relatives, which makes it a [hemp](https://genetixbay.com/knowledge/glossary/hemp.md) and cannabis specialist. It is invisible without strong magnification.

## In practice

Damage usually starts low and works up. Leaf edges curl upward, surfaces turn dull, bronze or russet, and [petioles](https://genetixbay.com/knowledge/glossary/petiole.md) can become brittle. In flower the [mites](https://genetixbay.com/knowledge/glossary/two-spotted-spider-mite.md) crowd into buds and onto [trichome](https://genetixbay.com/knowledge/glossary/trichome.md) stalks, leaving heads that look matted or greasy. By the time a grower notices, populations can number in the thousands per leaf. Confirm with a 40x or stronger scope; the mites look like moving beige dust. Most infestations arrive on clones, so quarantine and inspection of incoming material matter more than any spray. Clean [mother stock](https://genetixbay.com/knowledge/glossary/mother-plant.md) is the long-term fix. Check what is registered for cannabis locally before treating.

## Don't confuse with

- **Broad mite**: distorts new growth from the top; russet mites start lower and bronze leaves.
- **Two-spotted spider mite**: visible with a 10x loupe, makes [stippling](https://genetixbay.com/knowledge/glossary/stippling.md) and webbing.
- **Rust fungi or nutrient bronzing**: no mites under the scope.

## Related terms

[Broad mite](https://genetixbay.com/knowledge/glossary/broad-mite.md), [Two-spotted spider mite](https://genetixbay.com/knowledge/glossary/two-spotted-spider-mite.md), [Quarantine](https://genetixbay.com/knowledge/glossary/quarantine.md), [Scouting](https://genetixbay.com/knowledge/glossary/scouting.md), [Sulfur burner](https://genetixbay.com/knowledge/glossary/sulfur-burner.md)

## Read more

- [Broad mites on cannabis: life table, spread and control (plus russet mite summary)](https://genetixbay.com/knowledge/pests/broad-russet-mites.md)

## Sources

1. Colorado State University. Hemp russet mite, Aculops cannabicola. https://agsci.colostate.edu/agbio/ipm-pests/29895-2/
2. NC State Extension. Hemp Russet Mite in Industrial Hemp. https://content.ces.ncsu.edu/hemp-russet-mite-in-industrial-hemp