Introduction

Indoor cannabis cultivation offers numerous advantages, including controlled environments and enhanced security, thus Unveiling Common Pests and Diseases in Indoor Cannabis Cultivation is important. However, it also presents unique challenges, particularly concerning pest and disease management. In this comprehensive guide, we delve into the common pests and diseases that plague indoor cannabis cultivation, along with effective prevention and control strategies.

Understanding Common Pests

1. Spider Mites: These minuscule pests are among the most dreaded in indoor cannabis cultivation. Spider mites thrive in warm and dry conditions, making indoor grow rooms ideal habitats. They pierce plant tissues and feed on sap, causing yellowing leaves, stunted growth, and webbing on the plant surface.

Prevention and Control: Maintain proper humidity levels, regularly inspect plants for early signs of infestation, and employ biological controls like predatory mites or insecticidal soaps.

1. Thrips: Thrips are tiny insects that feed on cannabis leaves, leaving behind silver or bronze streaks and causing leaves to curl or distort. They can transmit viruses and weaken plants, affecting overall yield and quality.

Prevention and Control: Implement rigorous sanitation measures, including cleaning equipment and eliminating plant debris. Biological controls such as predatory insects and neem oil can help manage thrip populations effectively.

1. Aphids: Aphids are common sap-sucking insects that colonize cannabis plants, especially during the vegetative stage. They reproduce rapidly and can cause significant damage by deforming leaves, excreting honeydew, and transmitting diseases.

Prevention and Control: Introduce natural predators like ladybugs, lacewings, or parasitic wasps to control aphid populations. Regularly inspect plants and promptly remove heavily infested ones to prevent further spread.

Combatting Common Diseases

1. Powdery Mildew: Powdery mildew is a fungal disease characterized by white powdery patches on leaves, stems, and buds. It thrives in warm and humid conditions, making indoor grow rooms susceptible, especially if airflow is insufficient.

Prevention and Control: Ensure proper ventilation and air circulation within the grow room. Implement preventive measures such as maintaining lower humidity levels, spacing plants adequately, and applying fungicidal treatments as needed.

1. Botrytis (Gray Mold): Botrytis cinerea is a fungal pathogen that can devastate cannabis crops, particularly during flowering. It manifests as grayish-brown fuzzy patches on buds and flowers, eventually leading to rot and loss of yield.

Prevention and Control: Maintain optimal environmental conditions, including temperature and humidity control. Regularly inspect plants for signs of infection and promptly remove affected areas. Implement cultural practices such as pruning to improve airflow and reduce moisture retention.

1. Root Rot: Root rot is a common issue in indoor cannabis cultivation, often caused by overwatering, poor drainage, or soil-borne pathogens. It compromises root health, leading to wilting, yellowing leaves, and stunted growth.

Prevention and Control: Practice proper watering techniques, allowing the soil to dry out between watering sessions. Improve drainage by using well-aerated growing mediums and pots with drainage holes. Treat affected plants with beneficial microbes or fungicides to suppress root rot pathogens.

Integrated Pest Management (IPM) Strategies

Implementing an integrated pest management (IPM) approach is crucial for effectively managing pests and diseases in indoor cannabis cultivation. Key components of IPM include:

1. Cultural Practices: Maintain cleanliness, proper sanitation, and optimal growing conditions to minimize pest and disease pressure.

2. Biological Controls: Introduce beneficial insects, predatory mites, or nematodes to control pest populations naturally.

3. Mechanical Controls: Use physical barriers, such as sticky traps or screens, to prevent pest entry and trap flying insects.

4. Chemical Controls: As a last resort, employ chemical pesticides or fungicides, ensuring they are safe and approved for use on cannabis.

Conclusion

Successful indoor cannabis cultivation requires vigilant pest and disease management strategies. By understanding the common pests and diseases that afflict cannabis plants and implementing proactive prevention and control measures, cultivators can safeguard their crops and ensure optimal yield and quality. Remember, early detection and swift action are key to mitigating the risks associated with pests and diseases in indoor cannabis cultivation.

Every year cannabis cultivation becomes more widespread across the world, and with that, growers experience new blights.  In fact, new pathogens appear every year.  Most people have heard of Hop Latent Viroid, but there are others, such as Citrus Yellowing Vein Associated Viroid and Beet Curly Top Virus in cannabis.  

This article will explore Beet Curly Top Virus (BCTV). You will learn why BCTV is a pathogen you should worry about and, most importantly, how to prevent it from spreading into your garden. 

What is beet curly top virus?

Beet curly top virus is a well-known virus in traditional agriculture, with the first signs dating back as early as the late 1800s. Beet curly top virus has been known to infect over 300 different species of plants but has only recently been diagnosed in cannabis, particularly in hemp plants (cannabis sativa).

BCTV has been infecting industrial hemp for years but has only been recently positively diagnosed in cannabis, opening a much larger discussion on how it affects the plant. For years cultivators have seen the effects of BCTV and attributed it to genetic mutations, heat stress, and other common factors affecting cannabis. Now that we know BCTV can infect cannabis, it is vital to understand the signs and symptoms of the virus and how to prevent its spread.

What are the symptoms of BCTV in cannabis plants?

BCTV has many signs in cannabis plants. Common symptoms include contorted or twisted new growth, yellowing of leaves, and stunting in infected plants. Many symptoms, such as the upwards curling of leaves, are BCTV  symptoms that sometimes get misdiagnosed as heat stress. 

The effects of this virus can severely reduce the yield and quality of your flower. That’s why you must stay vigilant to quickly identify these symptoms and remediate the possible damage this virus can cause.

How is beet curly top virus transmitted?

Beet Curly Top Virus is only spread one way, through Leafhoppers. The virus has a symbiotic relationship with Leafhoppers, specifically the beet leafhopper. It will live in their guts and spread to the plants when the insect is munching on them. 

How likely is it for home growers to encounter beet curly top virus?

Home growers should be aware of BCTV as a possible threat to their grow, especially outdoor cultivators. In an outdoor garden, BCTV can quickly spread because plants are more exposed to leafhoppers, which are the only vector of the virus. 

However, indoor growers should be aware of the virus because it can be transmitted through seed. However, the likelihood of the virus transferring to other plants is minimal since you rarely find leafhoppers indoors.

Leafhoppers are most commonly found in the western United States, so many cultivators won’t necessarily encounter this problem in other parts of the world. Luckily, the virus needs either a host plant or a leafhopper host to survive, so there is no worry of transmission through soil or infected tools such as scissors or scalpels.

Is there a cure for beet curly top virus?

As of now, no product can cure beet curly top virus. Insecticides to kill or prevent leafhoppers from infecting their plants are a  growers’ best defense against the virus.  If you believe you have a plant infected with BCTV, it’s best to kill that plant so a leafhopper won’t be able to pick up the virus and spread it to other healthy plants. 

Many outdoor farmers use reflective mulches to deter leafhoppers from landing on their plants. BCTV can also spread through seeds, which is another reason why buying seeds from a reputable source is important. While we don’t currently have a cure, hopefully, with a greater understanding of the virus, better prevention methods will be discovered and can be implemented in everyone’s garden.

Many outdoor cannabis farmers use reflective (plastic) mulches to deter leafhoppers

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Conclusion

Beet Curly Top Virus is a serious pathogen that all growers should be on the lookout for in their grows. With no definitive cure, it is essential to know the symptoms to react quickly to remediate damage to your crops. It’s always better to be proactive instead of reactive; by maintaining a good pest management program and thoroughly scouting your garden, you can stay ahead of damage caused by BCTV. 

Keep learning to keep your garden greener,

Spenser

Used sources for this article

• Hu, J., Masson, R., & University of Arizona. (2021, June). Beet Curly Top Virus In Industrial Hemp. University of Arizona. https://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1931-2021.pdf
• Nachappa, P., Chiginsky, J., Hammon, B., & Colorado State University. (2020). Beet Leafhopper and Beet Curly Top Virus. Colorado State University. https://webdoc.agsci.colostate.edu/hempinsects/PDFs/Curly%20Top%20Beet%20Leafhopper%202020.pdf
• Rivedal, H. M., Funke, C., & Frost, K. E. (2022). An Overview of Pathogens Associated with Biotic Stresses in Hemp Crops in Oregon, 2019 to 2020. Plant Disease, 106(5), 1334–1340. https://doi.org/10.1094/pdis-11-21-2415-sr
• Melgarejo, T. A. (n.d.). Curly Top Disease of Hemp (Cannabis sativa) in California Is Caused by Mild-Type Strains of Beet curly top virus Often in Mixed Infection | Plant Disease. Plant Disease. https://apsjournals.apsnet.org/doi/10.1094/PDIS-04-22-0856-SC
• Giladi, Y. (n.d.). First Report of Beet Curly Top Virus Infecting Cannabis sativa in Western Colorado | Plant Disease. Plant Disease. https://apsjournals.apsnet.org/doi/10.1094/PDIS-08-19-1656-PDN
• Hemp (Cannabis sativa)-Curly Top. (2023, April 17). Pacific Northwest Pest Management Handbooks. https://pnwhandbooks.org/plantdisease/host-disease/hemp-cannabis-sativa-curly-top

Despite what its name may imply, jar rot is not a form of decay in your cannabis. Instead, mold develops from improperly dried and cured buds.

How does this happen? The environment and conditions for storage can be unsuitable for cannabis in many ways, ranging from insufficient air circulation in the jars to excess humidity in the room.

But, while it’s unsuitable for storing weed, it’s the perfect environment for mold growth.

Do you have questions? We’ll discuss how to prevent jar rot from ruining the buds you painstakingly grew.

We’ll also talk about what causes jar rot, how you can recognize it, and other types of mold on your cannabis. 

Does Jar Rot differ from Bud Rot?

Biologically speaking, jar rot and bud rot are the same. They result from botrytis⁽²⁾ (more commonly known as gray mold), a necrotrophic fungus that feeds by killing its host and eating the dead matter. In foodstuffs like strawberries and grapes, it makes them appear as though they’re rotting. In cannabis, it causes darkening and softening in the plants while the buds turn gray and dusty with mold⁽³⁾. 

If there is a difference between the two, it would be when the signs of botrytis appear. Bud rot is associated with buds that get infected with fungus during the flowering stage. As its name implies, jar rot appears during the buds’ drying, curing, and storing process.

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How to prevent jar rot from ruining your weed

Keep humidity levels low

One of the key factors that encourage the growth of botrytis and other types of mold is humidity. You must have optimal humidity levels during drying and curing to prevent jar rot. For drying, you need a relative humidity of 45-55%⁽⁴⁾, and curing requires something between 60-65%⁽⁵⁾. You can do this easily with the help of humidity packs like Boveda, which provides a way to maintain a relative humidity for your buds.

Botrytis also requires a certain humidity level for it to thrive. For the fungus to develop, it needs a relative humidity of 85% or greater and a temperature between 60-75°F (15-23°C)⁽⁶⁾.

Use the right storage

The best way to keep your buds mold-free is to use airtight containers. You can use any type of container as long as it proves to have an airtight seal. This can be in the form of stainless steel or plastic containers. But, the safest and most popular option are mason jars.

Mason jars provide an airtight seal which limits the exposure of your buds to moisture and oxygen, reducing the odds of mold and keeping your buds fresh for longer. Putting humidity packs in your curing jars is also a great way to limit the number of times you need to burp them. This is because the humidity pack is already regulating the moisture in the jars for you, meaning you don’t need to open and close your curing jars to let out moisture.

How do you recognize jar rot in weed

What does mold on dried cannabis look like?

Botrytis on dried cannabis appears like dust that covers the buds. It can easily be mistaken for kief at first glance, but taking a closer look would let you know that’s not the case. To confirm if your buds are indeed infected with jar rot, you need to pull apart the colas to check if the inside is pale gray and if the texture has become dry and cotton-like. 

It’s important to note that botrytis isn’t the only mold found in cannabis. There’s also powdery mildew, which appears as either gray fuzz or white powder on your plants.

Can you detect moldy cannabis by smell?

Moldy weed usually has a distinct musty smell to it. If your buds have an unpleasant musty hay odor to them, this is because they’re infested with mildew⁽⁷⁾. But, in cases like jar rot, it’s much harder to detect it through smell since it’s odorless⁽¹⁾. It’s also not ideal to use something as sensitive as your nose to test for mold is also not ideal, as you may inhale their spores.

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What causes Jar Rot in cannabis

What is the biological reason for mold?

Spores are why molds like powdery mildew and botrytis find themselves in plants and other places. Like seeds, they can lay dormant for a long period of time until they find a suitable environment. They can find themselves in your grow through the soil, water, and even air.

With the how out of the way, what about the why? Why does mold even exist, and why does it have to damage your plants to live? The purpose of mold is to break down organic matter and give back those nutrients to the environment⁽⁸⁾.

Which environmental factors cause mold?

Mold needs more than just a water source; it also needs the right temperature and an ample food source. The main environmental factors contributing to mold growth are humidity, temperature, and available substrate. Substrate can mean anything in this sense. It could be the soil your plants are growing on, or it could be the plants themselves. To mold, it’s just a source of nutrients since it’s unable to make its own.

For the temperature, molds generally need something between 60-80°F (15-26°C) to thrive⁽⁹⁾. Any higher or lower will cause the mold to stop growing, but this does depend on the type of mold you’re dealing with.

Can I still smoke or make hash out of weed with jar rot? 

Smoking moldy weed

It’s never a good idea to try and smoke moldy weed since it carries several health risks. One of the main concerns with it is how your body reacts to the mold, specifically your lungs. And while most people would get off with an irritated throat and a bit of coughing, some who are allergic to mold will likely end up with something more severe⁽¹⁰⁾.

In some cases, smoking moldy buds could lead to a fungal infection in the throat and lungs. And for those with a weakened immune system, the dangers could prove fatal to their health. Don’t think that it could be fixed by removing the mold from the buds. Even after being removed, certain fungi can leave metabolites called mycotoxins which are carcinogenic and a toxin to humans⁽¹¹⁾.

A few examples of molds that produce mycotoxins are powdery mildew, aspergillus, and fusarium. Strangely enough, botrytis is one of the few molds that don’t produce these dangerous metabolites⁽¹²⁾.

Making hash from moldy weed

If you can’t smoke moldy weed, you shouldn’t make it into hash either. While, at first, it may sound like a great idea to make hash out of your moldy buds, we advise against doing so. Since even if the heat does kill and remove the mold from your buds, there’s still the matter of mycotoxins that remain even after the mold is cooked off. This is because the metabolites can survive temperatures up to 210°C for an hour.

Making edibles from moldy weed

We also don’t recommend making edibles out of your tainted buds. That means making hash oil and shatter are out of the question. Again, it may seem like a smart idea, but it’s dangerous if you don’t know the type of mold you’re dealing with.

FAQ about Jar Bud Rot

Can you process moldy cannabis?

Technically, you could process moldy cannabis into hash oil, shatter, or hashish. Would it be safe to consume? It depends. If the mold doesn’t produce mycotoxins like botrytis, you’re free from carcinogenic and toxic metabolites. However, if it will affect the quality, potency, and flavor, it is a different matter. That answer is most likely.

Can you get sick from moldy buds?

Yes, there’s a good chance that if you smoke moldy cannabis, you could develop a fungal infection in your lungs and throat. The dangers of mold are especially concerning when it comes to those who are allergic and those with weakened immune systems.

Is white mold on weed toxic?

White mold or powdery mildew is indeed toxic. This is because it’s a type of fungus that produces mycotoxins, which are carcinogenic and toxic to humans.

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