So, perhaps you have successfully battled spider mites and feel your integrated pest management skillset has improved since eradicating them. Well buckle up, because russet mites are, if you can believe it, an even harder pest to get rid of. They are another almost invisible, microscopic mite that destroys cannabis and hemp plants.
Russet mites are some of the most unbelievably damaging and challenging to eradicate pests affecting cannabis and hemp growers today. Tough to locate and quick to reproduce, russet mites do not produce the noticeable webbing that identifies other common pest issues like spider mites. Their miniature size allows them to attach to new areas on clothing, in removed debris, and even on other pest insects like aphids and whiteflies, allowing them to easily hitchhike into an indoor grow. This is another reason why keeping your grow room santitized from OUTSIDE contaminants is so important (but inside, you want it to be teaming with life - the right kind of life).
Understanding & Detecting Russet Mites
Russet mites lay bright, transparent, round eggs in the spring. Following the egg's hatching, these mites go through two developmental nymph stages, which resemble adults. Breeding and life cycle time varies from 8-15 days based on room design and environmental conditions. Adults are tiny and wedge-shaped, appearing copper colored. Russet mites appear differently than many other mite species in that they only have two pairs of legs.
Russet mites, similar to broad mites, measure about 0.17mm in length. These mites tend to dwell on lower parts of the plant, gradually working their way up, feeding off the lower leaves and foliage first. Russet mites feed off the sap from the cannabis plant. This, in turn, stunts the plant's growth during veg, affecting its ability to grow more abundant flowers come harvest time. But they don’t stop at the foliage; russet mites are particularly attracted to flower resin, meaning they will often attack cannabis buds - aka, your money. All of this will slowly rob the plant of its vital nutrients. This is why many new farmers think they have a plant deficiency they cannot fix, because the symptoms of russet mites look like a deficiency. Over time, russet mite feeding has a severe impact on bud and flower production throughout a grow, making preventative control and early treatment the most economically viable treatment methods. Females overwinter inside the stems of affected cannabis plants as well!
More specifically, symptoms of russet mites are commonly yellowing leaves (chlorosis) and leaf curl ("taco-ing"), as well as stunted and slow growth, signs which are often mistaken for a pure nutrient or water deficiency. Cannabis fan and sugar leaves affected by these mites might appear glossy or wet-looking, while buds will begin to brown and eventually die. If unseen or left unchecked, russet mites will continue to spread and reproduce, ultimately sapping an entire plant.
correctly identify whether there are russet mites. Remember, as I mentioned before, the symptoms of a mite infestation are similar to nutrient deficiencies or pH imbalances. Therefore, you will want to make sure you're 100% certain you're dealing with russet mites before starting a treatment.
Once you've identified russet mites on your cannabis plants, it's now time to try and treat them so you can save as many plants as possible. Although there is really not much you can do about a late-stage infestation, there are a few different treatment methods for dealing with russet mites if they are caught early enough.
Treatments for Russet Mites
As far as we know, there are no really effective biological controls for russet mites. If you catch them early enough, there are some natural, organic insecticides that will be effective at combating them. If your crop manages to survive a russet mite infestation, we recommend you sterilize your entire grow afterwards, and start over with new soil.
Insecticidal plant soaps are great for identified trouble areas that need spot-treating. And you should do this IMMEDIATELY after you’ve identified an infestation. These soaps are ideal for use on smaller russet mite infestations as well as a possible LAST MINUTE attempt on early flowering cannabis plants. Be cautious, and make sure to avoid getting the soap on your buds. Consider using this simple method multiple times for the best possible results.
Here are a few other organic insecticides that may be effective against russet mites.
When it comes to eradicating heavily infested cannabis gardens, it's always better to prevent than treat. Therefore, always make sure your cannabis plants are growing in a pleasant environment with excellent ventilation and proper air circulation coming from a variety of areas across the room. If you’re growing indoors, be very careful about introducing “foreign contaminants,” i.e. unintentionally bringing in biology from outside. Please remember to always inspect your cannabis plants DAILY and act quickly as soon as you see any signs of plant stress. Obviously, Russet Mite infestations are much easier to handle when caught and identified early on.
About the Author
Daniel Enking is the founder of Everflux Technologies. He is a life-long environmentalist and practical dreamer who is obsessed with resource efficiency and imaged an "everything recycling machine" at age 10.