Russet Mites are a big problem with cannabis plants that are growing on the west coast of United States and it’s moving eastward.
The mites can do some pretty good damage to the outdoor growers.
They are so small, and just hitch a ride in the wind or even on flying insects.
The same with indoor grows as well; hemp russet mites come from the outside go on clothes then infest your plants when you’re least expecting it.
These mites can go undetected for quite some time before you notice you have a real problem kind of like when spider mites infest your garden.
When your plants are infected, it may take some time to kill these invaders.
Let’s check out some of the signs to see if they are invading your cannabis plants,
Signs of Russet Mites
- May seem like an Over watering issue
- Look like a type of nutrient deficiency
- Yellowing of leaves
- Browning of leaves
- Can be confused with the tobacco mosaic virus
- Leaves show signs all over the marijuana plant not just in specific areas
- Leave curl at edges
- Can Look like heat burn, heat damage
- Yellow or brown spots on leaves
- New growth may be stunted
- Leaves may droop
- They will be next to the vein of the leaf, use microscope to diagnose
What are Hemp Russet Mites?
Russet Mites are tiny, when I mean small they are at a level where you require a microscope to see them.
The size of the russet mite is around . 0.2 mm, much smaller than spider mites. According to the Colorado State University.
The hemp russet mite or also known as Aculops cannabicola have a pale beige body and leave no webs as spider mites do.
Russet mite life cycle is around 30 days at around 80 F.
The adults lay between 10 -50 eggs and what’s crazy is the mites lay eggs inside the marijuana plant. Yes inside.
Which makes them very hard to get rid of.
You can find them living on leaves stems and branches.
Not only do they lay eggs inside your cannabis plants the russet mites feed on leaves.
The mites turn the leaf to chlorosis and necrosis. Then the leaves die.
Russet mites also feed on resin when your cannabis plants are in the flowering stage.
So it’s best to stop these trichome hunters before your plant’s switch over to flower.
Broad and Russet mites are know to turn your cannabis buds a light brown color when infected during the flowering stage.
Another sign to keep an eye on when growing .
How your cannabis plants get Russet Mites
Here are some of the most common causes of an infestation.
Unclean grow space either outside or indoors.
Russet mites hide in greenhouses in the smallest corner.
Travel by the wind or on flying insects and from clothing.
Introduced to your garden via some potting soil mixes.
Can be found on contaminated clones or clippings.
Big problem for outdoor growers in the western US, moving eastward.
Here is a short video of what they look like under a microscope,
How to kill Russet Mites
It is best to have some portable microscope if you don’t have one already for you to try and spot them if you suspect issues.
When treating your mite problem, it is best to start from the bottom of the cannabis plant to the top.
- Start using beneficial nematodes
- Remove old and infected leaves
- Spray your IPM before the lights go out (never spray when your lights are going to be on for hours at a time)
- Treat regularly and be diligent they are hard to get rid of and come back just like the spider mites
- After you notice improvement continue for another month if possible before flower
Natural and Organic Remedies
Best to treat before flower, but will still work in early flower before the trichome development.
Note this will not take care of the eggs , you will need another solution listed below.
Use a 1:1 ratio of 90 percent or higher alcohol with water and spray on your cannabis plants
Neem oil an excellent natural remedy to help your garden for a various number of issues known to be an insecticide, miticide, and fungicide.
The Neem oil can be used in getting rid of russet mites when applied at the early stage.
Do not use too often and not recommended in flower. It’s Recommended to use diluted with water.
Safer Soap is a 3 in 1 solution for mites, insecticides and a fungicides, this is USDA approved and can be used on organics.
It is not recommended to use past the second week of flower. Safer soap contains sulfur.
Green Cleaner is an all natural way to stop all kinds of mites hemp russet included. The ingredients are corn oil, soybean oil, iso alcohol, magnesium sulphate, quillaja saponaria, sodium chloride.
The great thing with green cleaner mites do not become immune to it! Check it out.
Insecticide soap is another way to stop the mites when first noticing them, made from plant derived fatty acids.
This soap will suffocate the mites and affect their feeding patterns. Remember to spray before the lights go out.
Enssentri ic3 is an insecticide that uses peppermint and rosemary wintergreen oil along with other organics.
Used to block the neurotransmitters of the insect. Also recommended for bed bugs.
This solution does not last too long on the plants only around 7-8 hours so multiple application may be required.
Diatomaceous earth is a natural food supplement that is made from fossilized plankton. Diatomaceous can also be used in the soil when growing to prevent hemp russet mites from infesting your plants it also contains silica.
This is just a preventive measure to stop the mites from infesting your plant.
For proper handling here is a resource from: The International Diatomite Producers Association (IDPA).
Beneficial nematodes can be used for growing outdoors when keeping soil out over the winter, can prevent a future outbreak in the spring and summer when your plants are starting back up.
Organocide is an organic 3 in 1 solution for miticide, insecticide, and fungicide. I have used it in root aphid outbreak.
Organocide uses all natural oils and ingredients. This may be an effective way to get rid of the mites for your garden.
Wettable Suplur is a great alternative it is inexpensive and last a while and is a known to kill russet and broad mites.
An organic compound sulfur is safe to use on your plants in various stages. This is from a reader of ours that gave us the heads up mentioned in the comments, 2 tsp per gallon of water and spray on affected area.
This ” will kill all of them and you can even spray it on affected flowers and will not burn the buds as long as its done in dark period”.
Another bonus of wettable sulfur is that is can help against powdery mildew.
Bonide Sulfur Plant fungicide is one type of sulfur your can apply is micronized perfect for spraying.
Safe for fruits and vegetables, organic and able to control mites, thrips.
Smite a proven killer for spider mites, also works for russet mites!
This miticide is a non toxic, biodegradable, organic solution for a preventative and to eradicate your russet mites.
Smite works by going inside the abdomen and suffocates the mites. What also is great is it works on contact and even kills the eggs left by russet mites.
The ingredients are all natural and contain Peppermint, Geranium,, Cotton Seed, and Rosemary oils which are micronized done to 1 micron by a special process.
Smite is safe to use on all fruits , vegetables and cannabis plants at all stages of growth.
After spraying on your plants the miticide with natural biodegrade and leave minimal to no residue after.
This can be a great solution to end those russet mites for good and make sure they do not come back.
Bugs and Predators
Lady bugs, a natural russet mites predator, can be introduced to your marijuana garden to try and eradicate the russet mite.
They like to eat the mites all day long. Usually, the ladybugs can be found at your local grow store or on Amazon with live delivery!
Predatory Mites such as Amblyseius cucumeris, A. fallacis, and A. swirskii). These predatory mites can be hung from the bottom of your plant’s branches which should be stripped of leaves.
Mostly available through a beneficial insect supplier in your area. Or even on Amazon!
Avid is a crazy strong miticide that is not recommended because it is very expensive and harsh on your plants should be used as a last resort. Also, do not use avid when in flower if you attempt it.
Azamax is a product that can best use a s a 3 in 1 insect killer; it uses Azadirachtin with food grade formulation to stop your mites in its track, through starving a disrupting the nervous system.
Floramite is a very strong miticide just like avid and is not recommended to use with cannabis plants. If you do caution is strongly advised.
The hemp russet mites are a big problem for cannabis plants out there because they can go undetected for so long do to the fact that they are so small.
It’s best to have a microscope to spot these destructive insects.
Make sure to treat on a regular basis if you have problems because it’s hard to get rid of russet mites.
If you’re growing outdoors or in greenhouses in the western coastal us, your are bound to have them show up if you’re not too careful.
Just try and keep diligent in preventive measures and keep an eye out for these cannabis plant killers.
These mites are very hard to kill and seem to become immune to some of the solutions recommended as noted from other growers in the community.
Don’t let that discourage you.
Keep up the fight.
Have you had russet mites infest your marijuana plants?
What did you use to stop them?
Let me know in the comments.
Grow on my friends.