Mitchell Stern
- Dec 5, 2022
- 3 min read

How to Get Rid of Russet Mites

Updated: May 23

Russet mites are a cannabis growers' worst nightmare. They feed on all types of cannabis plants, including European fibre cultivars, Southeast Asian drug landrace varieties, Afghan landrace varieties, as well as ruderals.

Russet mites feed primarily on petioles, leaflets, and the pistils of female flowering plants.

In this article we're going to discuss:

Signs & symptoms of russet mite infestations
How to get rid of russet mites
Garden cleanliness & pest prevention

Russet Mite Taxonomy

Early Signs of Russet Mites

How to Get Rid of Russet Mites

Russet Mites on Plants

Bibliography

Russet Mite Taxonomy

Russet mites, or Aculops cannabicola, are soft-bodied, sausage-shaped, and exceptionally small. Mature females measure around 0.2 mm long and only 0.45 mm wide.

They have two pairs of legs and their bodies are made of two distinct sections: the gnathosoma (mouthparts) and the idiosoma (body).

The legs of the russet mite extend from around the gnathosoma, toward the front.

The hemp russet mite

We don't know very much about the lifecycle of russet mites. Outdoor populations likely overwinter in among seeds and indoor russet mites remain on plants year round.

Russet mites migrate toward the tops of dying plants and tend to spread to other plants either by wind or splashing water.

They thrive in environments around 80 degrees Fahrenheit (27 degrees Celsius) adn 70% relative humidity.

Differential Diagnosis

The morphology, coloring, small size, and lack of webbing make them easy to distinguish from spider mites.

Early Signs of Russet Mites

Russet mite are practically invisible to the naked eye. Damage first appears on leaflets that will curl at the edges, followed by chlorosis and necrosis.

Petioles become brittle and leaflets break easily.

In cases of severe infestations, russet mites will crowd the plant, giving leaflets a beige appearance.

Russet mite damage

How to Get Rid of Russet Mites

There aren't very many ways to control russet mites. Nevertheless, we present the following control methods in order from most recommended to least recommended.

Prevention

Cleanliness is the best defense against a russet mite infestation. Make sure to only use clean seed to prevent introducing overwintered russet mites to your garden.

Indoor gardeners should also abide by all generally-accepted cleanliness practices, including:

Wearing decontaminated coveralls over clothing and covering hair when working around or near plants.
Dawning clean shoe covers when entering a growroom
Filtering any air that enters the grow space

Greenhouse growers are advised to maintain a three meter wide 'weed-free zone' around their greenhouse at all times.

All indoor and greenhouse growers should decontaminate walls, floors, ceilings, and equipment; with a lime-sulphur spray, fish oil soap, or solution of household bleach (sodium hypochlorite) diluted to 5%.

Early signs of russet mites

Biological Control

There is no known effective biocontrol of russet mites, however some subspecies do appear to be susceptible to Zetzellia mali, a tiny predator that is not commercially available.

A biological control fungus called Verticillium lecanii may also help reduce russet mite populations.

Homeopronematus anconai, a predatory tydeid mite, has been found to be effective under certain conditions; and is resistant to abamectin.

Phytoseiulus persimilis does not feed on russet mites and will actually prey upon homeopronematus anconai; making situation worse.

Chemical Control

Neem oil and sulphur are effective against some russet mites, but not Aculops cannabicola.

Cinnamaldehyde has been proven effective against russet mites, including Aculops cannabicola; as has abamectin.

Hexythiazox, a growth hormone, selectively kills immature russet mites.

According to data that was later unpublished, one researcher managed to kill russet mites by enclosing a potted plant in a plastic bag and filling the bag with CO2 for 2 hours.