How To Deal With Broad Mites On Cannabis Plants
Cannabis plants aren’t immune to pests. However, by acting fast and using the right treatment, you can minimise the damage of even the toughest pests, including broad and russet mites.
Russet and broad mites are tiny garden pests that can wreak havoc on cannabis plants, stunting their growth and destroying your yields.
In this article, we take a look at both broad and russet mites and show you exactly how to treat them.
WHAT ARE BROAD/RUSSET MITES?
Broad mites, also known as Polyphagotarsonemus latus, are a garden pest that can be regularly found on a variety of plants, including grape vines, apple trees, and of course, cannabis.
Despite their name, broad mites are tiny, with female mites measuring roughly 0.2mm and males measuring only 0.1mm. They can be found around the world, especially in greenhouses.
On cannabis plants, broad mites tend to lay eggs on the underside of new leaves. This is usually where they dwell and feed, leaving behind a toxic saliva that causes malformations and stunts the development of cannabis plants.
Russet mites, or Aceria anthocoptes, are another type of microscopic mite that can affect cannabis and hemp plants.
Similar to broad mites, russet mites measure about 0.17mm. However, they tend to dwell on lower parts of the plant, gradually working their way up, feeding off lower leaves and foliage.
Russet mites feed off sap from the plant, slowly robbing it of nutrients. This in turn stunts the plant’s growth, affecting its ability to flower come harvest time. Unlike broad mites, however, they are particularly attracted to flower resin, meaning they’ll often attack cannabis buds.
What makes broad and russet mite infestations so detrimental is the fact that the mites aren’t visible to the naked eye. Plus, the symptoms of these mites are similar to those of nutrient deficiencies or pH imbalances, making them even harder to detect.
The symptoms of russet and broad mites are usually characterised by yellowing foliage and stems, curling and/or drooping leaves, and stunted growth. Foliage affected by these mites might appear glossy or wet-looking, while buds will begin to brown and eventually die.
If left unchecked, both mites will continue to spread and reproduce, ultimately sapping an entire plant.
HOW TO TREAT BROAD OR RUSSET MITES IN CANNABIS PLANTS
If you notice any of the symptoms mentioned above in your plants, it’s important you quickly identify the root cause of your problem.
Using at least 60x magnification, closely inspect the affected parts of your plants to identify the mites.
Remember, the symptoms of a mite infestation are similar to nutrient deficiencies and pH imbalances. Hence, you’ll want to make sure you’re 100% sure you’re dealing with mites before starting a treatment.
Once you’ve identified mites as the cause, it’s time to treat your plants. Here are some different treatment methods for dealing with broad or russet mites on cannabis plants.
Neem oil is a great all-around solution for a wide variety of pests, including broad and russet mites. It is available from most grow shops and gardening supply stores.
Using neem oil is simple; just mix it in a mister according to the packet instructions and apply to the affected areas of your plant.
Keep in mind that neem oil will leave behind an unpleasant taste, so always avoid spraying it on your buds.
Also, while neem oil is an all-natural form of pest control, it can be very harsh. Hence, you won’t want to use it for much longer than necessary.
To limit your use of neem oil, we recommend applying it to your plants once, then monitoring their progress over the next 1-2 days before applying the oil a second time.
Pay close attention to the areas of your plants affected by the mites and make sure to check them with magnification after your first round of treatment. Then repeat this process as necessary until the mites are gone.
If you’re dealing with a hardcore infestation, feel free to apply neem oil on a daily basis. This will eventually kill off both broad and russet mites. Just remember that it’ll also put your plants under a lot of stress, so they’ll need a bit of extra TLC after the treatment is through.
Neem oil serves as a completely natural way to protect your cannabis plants against pests.
Neem oil serves as a completely natural way to protect your cannabis plants against pests.
If neem oil isn’t enough to protect your plants from mites, we recommend using a natural insecticide like:
- Essentria IC3: Essentria IC3 is made up of a mix of horticultural oils designed to manage a variety of garden pests. It can be applied directly to the plants using a mister and should be reapplied every 8-12 hours until the mites disappear.
- Spinosad: Spinosad is an organic insecticide that kills pests on contact. Try applying it directly to the affected parts of your plant once a day for multiple days until the mites are gone.
Insecticidal plant soaps are great for spot-treating parts of your plants affected by russet/broad mites.
This makes them ideal for use on smaller infestations as well as flowering plants. Just make sure to avoid getting the soap on your buds. Consider using them multiple times for best results.
Both essential plant oils and horticultural oils are becoming increasingly popular, especially among gardeners looking to avoid the harsh chemicals of regular insecticides. Some common natural oils used to control garden pests include eucalyptus, rosemary, lemon, and cinnamon.
Just like neem oil, these oils can be mixed with water and applied liberally to the foliage of your plants with a mister. Just remember that these oils possess strong aromatic qualities that will affect the flavour and aroma of your plants; so avoid getting them on buds.
Unfortunately, sometimes mites can be so hard to deal with they leave you no choice but to turn to time-tested chemical insecticides.
While these products contain harsh chemicals that’ll stress your plants and produce potentially toxic run-off, they are extremely effective at dealing with a wide variety of garden pests.
Most of these products are designed to be applied to the affected parts of the plants and left to work for extended periods of time. In some cases, you may need multiple applications to ensure the mites have left your plants.
After that, remember to thoroughly flush your soil. Then you can pump-up your nutrient routine again.
PREVENTING BROAD/RUSSET MITES IN THE FUTURE
When it comes to dealing with garden pests, it’s always better to prevent than treat. Therefore, always make sure your plants are growing in a good environment with plenty of ventilation/circulation and the right temperature/humidity levels.
Plus, always make sure to inspect your plants regularly and act quickly as soon as you see any signs of stress. Mite infestations are much easier to handle when caught early.
Russet and broad mites commonly affect cannabis, destroying growth and ruining yields. In this blog, we explain how to treat and prevent broad/russet mites.
Hemp Russet Mites
Hemp russet mites are tiny bugs that attack cannabis plants. In fact, they are so small you can only see them with a magnifier unless there are thousands of them infesting your plant. They live the the crevices of leaves, stems or buds, and the initial symptoms are not that serious. Many growers may not realize they have a bug infestation, and it’s common for growers to confuse the symptoms for other problems such as mold, fusarium, pollen, tobacco mosaic virus , overwatering , a nutrient deficiency or heat damage .
You may see curling on the edges of leaves, and buds may start dying (hemp russet mite leaf damage picture by thehumboldtlocal)
Hemp russet mites are tiny. You often won’t see them until you have a full infestation. They may appear as a beige or yellow mass (typically towards the tops of the plant). This hemp russet mites picture is by grow.nation.
The following two pictures of Hemp Russet Mites (Aculops cannabicola) were taken in Bloomington, Indiana by Karl Hillig. This picture shows hundreds of microscopic mites on the petiole of a Cannabis leaf.
These microscopic four-legged mites infested Cannabis plants in a greenhouse at Indiana University. This picture shows them on a leaf petiole that was about 2 mm wide. By Karl Hillig.
Symptoms of hemp russet mites on cannabis include:
- Symptoms often worst towards the tops of the plant
- Bugs are pale, typically either tan or yellow. In big enough numbers they can cause parts of the cannabis plant to look beige or yellow.
- Sometimes mistaken for fungus, mold or pollen.
- Tops of plants droop, especially where there is a big infestation
- Curling of the leaf edges (on some plants)
- Dull-colored and leaves or stems, which may also become brittle. These affected areas are where bugs are living inside the plant tissue.
- Brown or yellow spots (from leaf stress, not visible bites)
An intense hemp russet mite infestation on cannabis plants can be difficult to diagnose because it’s hard to see the individual bugs
The yellow mass isn’t mold or pollen. It’s actually an infestation of hemp russet mites
About hemp russet mites
- Can reproduce and attack cannabis plants all year round
- Most harmful in the flowering stage when buds get infested
- Indoors, fans can spread mites
Unfortunately, hemp russet mites are one of the toughest cannabis pests to get rid of. They lay their eggs inside the plant which makes it very difficult to kill their eggs.
- Grow from seeds (hemp mites and eggs cannot survive on seeds). If you start from seeds, your plants will not get hemp russet mites unless they get infected by some other source
- Treat and quarantine all new plants (even if they seem healthy) to ensure they don’t have hemp russet mites (or spider mites)
Time to get rid of hemp russet mites for good.
Solution: How to Get Rid of Hemp Russet Mites On Cannabis
Once you’ve actually identified that the bugs you have on your cannabis are hemp russet mites, it’s time to get rid of them! When it comes to hemp russet mites, a lot of the “standard” miticides are not as effective and you’ll notice these particular mites aren’t listed on the labels.
Hemp russet mites can be one of the toughest marijuana pests to get rid of, but it can be done if you stay vigilant!
- Consider tossing your plants – I know it can be a hard pill to swallow, but if you have an intense infestation, sometimes the easiest thing to do is to get rid of the plants, treat the room thoroughly, and start over. However, make sure you know where you got the mites in the first place or you may end up infected again!
- Treat often – You may have to treat several times a week or even daily if you have a terrible infestation that won’t go away. This can be very difficult on your plants.
- Spray Before Lights Go Out – Whenever treating plants with a spray, do it before the lights go off so that your plant is less likely to get burned!
- Read Instructions – Make sure to read the full instructions of each bottle and follow them when treating your plants. You will save yourself a lot of big headaches!
- Repeat treatments weekly for 5 more weeks after mites are gone – After you think hemp russet mites are completely gone, don’t stop! Treat your plant with a different treatment at least once a week for 5 additional weeks. If you don’t completely eradicate them they’ll come back with a vengeance and be even more resistant to whatever you throw at them.
1.) Neem Oil
Neem Oil will leave an unpleasant taste/smell on buds when used to treat flowering plants, so again, don’t let this stuff get near your buds! There’s also some evidence Neem oil may be harmful to humans so use with care! That being said, Neem oil is an all-natural remedy that is very effective against many different types of bugs and mold, including hemp russet mites.
Neem oil can be rough on your plants so you don’t want to use it more often than you have to because your plants will suffer. However, if you get desparate treating plants daily with Neem oil is very effective at killing hemp russet mites when nothing seems to be working.
You will need a mister (also called a “One-Hand Pressure Sprayer”) to spray all the leaves evenly, since neem oil and water can separate easily.
2.) Essentria IC3
Essentria IC3 Insecticide is a mix of various horticultural oils that is organic and safe for humans. It is often marketed as a “bed bug killer” but it can be effective against hemp russet mites when the plants are treated regularly. Unfortunately it only stays effective on the plant for about 8 hours so you will want to either apply this daily or combine with other options. You will need a mister (also called a “One-Hand Pressure Sprayer”) to spray all the leaves evenly.
3.) Insecticidal soaps
Fatty acid salts or insecticidal soaps can be a good choice against hemp russet mites. They weaken the outer shell of hemp russet mites but are safe to use on your plants and they don’t leave much of a residue which could kill beneficial bugs in your garden.
With soaps, just like horticultural oils, coverage is very important as it does not stay on your plant for long, so follow-up applications may be necessary. Although this is considered safe, avoid getting any on your buds!
This will not get rid of hemp russet mites on its own, but it is less harsh on your plants than some of the other options and so it can be a great way to supplement the other treatments you’re doing.
Natria Insecticidal soap can be a good option Another insecticidal soap that can be used against hemp russet mites is Safer Brand Soap
4.) Mighty Wash
Mighty Wash may help rid your grow room of hemp russet mites. Spray plants 15 minutes before lights out, making sure to drench the foliage under the leaves as well as the top of your soil. You want to use a spray bottle or mister. Use a fan to blow on your leaves to help things dry. Treat your room more than once, even if you believe the hemp russet mites are gone.
Use Mighty Wash with a One-Handed Power Sprayer for the best results!
Avid miticide is strong stuff with harsh chemicals, and is incredibly expensive, but it can sometimes do the job when nothing else is working. This is a systemic insecticide, which means it works by infiltrating the inside of plant tissue and killing bugs that way. Because of that it should NOT be using in the flowering stage (you don’t want this stuff inside your buds). However, many growers report that this is the only thing that consistently works for them. Always use Avid as directed and only as a last resort! You will need a mister (also called a “One-Hand Pressure Sprayer”) to spray all the leaves evenly.
Don’t use this product more than once or twice in a row or your mites may become resistant. This should stay in your plant’s system for several weeks. If you’re going to be using systemic insecticides, switch back and forth between this and another one like Forbid. Make sure to follow the instructions!
Forbid miticide is sort of like Avid in that it is made of strong stuff with harsh chemicals and is also expensive. This is a systemic insecticide, which means it works by infiltrating the inside of plant tissue and killing bugs that way. Because of that it should NOT be using in the flowering stage (you don’t want this stuff inside your buds). However, many growers report that this can be the only thing that consistently works for them. Always use Forbid as directed and only as a last resort! You will need a mister (also called a “One-Hand Pressure Sprayer”) to spray all the leaves evenly.
Don’t use this product more than once or twice in a row or your mites may become resistant. This should stay in your plant’s system for several weeks. If you’re going to be using systemic insecticides, switch back and forth between this and another one like Avid. Make sure to follow the instructions!
7.) Diatomaceous Earth
Diatomaceous Earth is basically fossil dust which you mix in with the top of your soil, and anywhere else in your room (window sills, doorways, etc). This powder-like substance is harmless to mammals and plants, but is incredibly sharp at the microscopic level. Therefore it will tear and dehydrate hemp russet mites on physical contact. This will not get rid of an infestation, but can help prevent, control and slow things down when used effectively! When it comes to hemp russet mites, you want to use every tool you can!
Hemp russet mites don’t like the heat. Some growers will try to get rid of them by on small plants or clones by dunking the plants in hot water (105°F / 40°C) for 10-20 minutes. I’ve also heard of growers try to reduce their number by overheating the grow space to 115°F (46°F) for an hour. Be careful as this can be dangerous if you don’t take safety precautions, and any heat method strong enough to kill the mites will likely hurt your plants.
9.) Predatory Mites
Some types of predatory mites, like Amblysieus andersoni mites, may target hemp russet mites. Supplementing your garden with extra predators can help bring down hemp russet mite numbers. However, it’s not enough to fix the problem on their own and unfortunately a lot of the other remedies on this page may also kill predatory mites.
If you don’t want to use any pesticides, get predatory mites to help eat all your hemp russet mites!
- Bronze or brown patches
- Brown or slimy roots
- Brown or yellow leaf tips/edges
- Buds dying
- Buds look odd
- Bugs are visible
- Curling or clawing leaves
- Dark leaves
- Drooping plant
- Holes in leaves
- Mold or powder
- Pink or purple on leaves
- Red stems
- Shiny or smooth leaves
- Spots or markings
- Twisted growth
- Wilting leaves
- Yellow between leaf veins
- Yellow leaves
This page is part of our Plant Doctor series. You can use our tool to filter by symptom and help diagnose your plant.
Hemp Russet Mites Hemp russet mites are tiny bugs that attack cannabis plants. In fact, they are so small you can only see them with a magnifier unless there are thousands of them infesting