Hemp Russet Mite Etymology:

The binomial name, Aculops cannabicola, is composed of two words. The first word, “Aculops”, is “Acul-“, meaning needle, and “-ops”, meaning strength or power. Like with many other specialists, the species name refers to its host, in this case “cannabi-” meaning Cannabis, and “-cola”, meaning “inhabitor”. The common name Hemp Russet Mite refers to its specialization on Cannabis plants, and its status as a russet mite, a member of the mite family, Eriophyidae.

Hemp Russet Mite Ecology:

Like most mites in the family Eriophyidae, the Hemp Russet Mite (Aculops cannabicola) is a specialist that feeds exclusively on Cannabis. Research relating to this family of mites in general, and the Hemp Russet Mite in particular, is in need of more extensive taxonomic and bionomic work. Although the vast majority of documented russet mites cause minor, incidental damage to their hosts, several are known to vector viruses and other crop plant pathogens, induce blisters, galls, and other immune responses in plants. This is why common alternative names for the Eriophyidae are blister mites, gall mites, and russet mites. In the case of the Hemp Russet Mite, phytotoxic saliva causes a rough, crinkled, corrugated damage to leaves, often creating thinly ridged shelter for the worm-like bodies of the Hemp Russet Mite to colonize and feed in relative safety.

Symptoms of Hemp Russet Mites:

Roughly crinkled leaf exterior is the major symptom of Hemp Russet Mite presence and can often be found on the top of the plant, where growth may be stunted. In sever cases of infestation, it is common for the leaves of the infested plant to bend and gnarl, and colonies of mites can appear like fine dust particles in large concentrations. This damage looks similar to that caused by the Broad Mite (Polyphagotarsonemus latus), which also uses phytotoxic saliva to create its damage profile.

Treatments for Hemp Russet Mites:

Chemical:

In vegetative propagation, micronized sulfur or a suffocating compound, like horticultural oil for vegetative Cannabis, can be highly effective at reducing Hemp Russet Mite populations. In other crops, systemic pesticides are common methods of treatment, specifically acaricides. These pesticides are inappropriate for Cannabis crops, however, because of their systemic movement through plant tissue and their long residual time. For these reasons, systemic pesticides are likely to remain present in the cannabis plant’s system until harvest, contaminating the end product.

Biological:

The application of predatory mites, such as the Swirskii Mite (Amblyseius swirskii) or Cucumeris Mite (Neoseiulus cucumeris), is appropriate when cannabis plants are flowering. A prophylactic introduction and maintained population of predatory mites such as these are usually a cost-effective strategy for eliminating Hemp Russet Mite infestations, both in residential and commercial spaces. The use of predatory mites also works well to eliminate Western Flower Thrip, Broad Mite, and Silverleaf Whitefly infestations. This integrated pest management strategy is especially useful when the quarantine of new plants isn’t possible.

Cultural:

The key to overcoming Hemp Russet Mite infestations is recognizing their damage and implementing treatment methods as early on as possible. Because the mites quickly spread and cause irreversible damage while feeding, time is of the essence when trying to eliminate an infestation. Carefully removing colonized tissues or whole plants can help reduce the spread of the Hemp Russet Mite significantly and make the overall successful treatment of the cultivation space much more likely. Keeping new Cannabis plants quarantined and limiting exposure of the current crop to the environment also helps mitigate the chance for colonization. As specialists, Hemp Russet Mites require other Cannabis plants to survive. This narrows their potential sources of contamination significantly. Because they have such small bodies, Hemp Russet Mites can move short and long distances by “questing” on air currents. “Questing” involves moving to high parts of the canopy and raising the mite’s body in order to catch the air moving around it. More commonly, Hemp Russet Mites are transported on plant material