A Comprehensive Guide about the Bud Rot Fungus in Cannabis Plant

Bud rot is every cannabis farmer’s nightmare. That’s mainly because the disease normally doesn’t present warning signals until it has progressed to advanced stages.

So, suppose you’re harboring ambitions of becoming a marijuana cultivator. In that case, it’s essential to understand everything there is to know about this contagious illness and how to prevent or mitigate its effects.

Fortunately for you, we’ve prepared a comprehensive guide to bud rot. Read on to learn more about one of marijuana’s deadliest fungal diseases.

A Comprehensive Guide about the Bud Rot Fungus in Cannabis Plant 1

Introducing Bud Rot

The most effective way to address any disease is to understand its causes, symptoms, and risk factors. That applies to bud rot as well.

But just what is bud rot?

Bud rot is a botanical fungal disease known to affect many plant species, with cannabis being one of the common victims. The disease is also known as bud mold, gray mold, and botrytis.

True to its name, bud rot mainly affects cannabis flowers (also called buds). The softer tissues around the flowers create an easy passageway for the fungus to enter the plant and begin its destructive trail. However, symptoms of invasion are often observable as far down as the plant’s lower stems.

What Causes Bud Rot?

Bud rot is caused by the Botrytis cinerea fungus. The following genetic and environmental factors can increase marijuana’s susceptibility to bud rot;

1.      High Relative Humidity Level

Molds usually flourish under humid conditions, and Botrytis cinerea is no exception. So, while bud rot is generally not a respecter of seasons, the disease is more common during humid months.

2.      Increased Precipitation

Precipitation and high humidity levels share one thing in common – they can lead to moisture deposits on plant surfaces. That consequently means that bud rot is equally rampant during wetter seasons.

Remember that precipitation doesn’t only relate to rainfall. It also encompasses aspects like snowfall and hailstorms.

3.      Cooler Temperature

Like any plant, cannabis thrives best under certain temperature conditions. Subjecting your marijuana crops to temperatures outside the prescribed range is the surest way to set them up for failure. Cooler temperatures are especially linked to fungal infections like botrytis.

4.      Reduced Air Flow

Very low temperatures and very high humidity are bad enough for cannabis plants. But it only worsens if the growing environment is also deprived of ample air circulation.

Reduced airflow means that any moisture deposited on cannabis buds will stay there for much longer. This only makes the plants more susceptible to bud rot.

Type of Strain – Dense and Fat Buds

The cannabis plant produces numerous species. These species may also contextually be referred to as strains, cultivars, or varieties. Cannabis strains differ in their genetic composition and physical appearance.

For instance, most indica-based cultivars tend to grow into dense foliage while also producing denser buds. This means that such trees retain moisture much longer, providing the perfect breeding ground for fungal infections like botrytis. 

A Comprehensive Guide about the Bud Rot Fungus in Cannabis Plant 2

Photo Credit: Pixabay.com

How Does Bud Rot Develop?

Bud rot develops when Botrytis cinerea makes contact with your cannabis plants. The fungus initially attacks the stem located on the inside of a bud.

Once Botrytis cinerea makes contact with the tender stems inside the buds, it will either penetrate the buds’ inner tissues immediately if there’s an open wound or linger on the surface if the conditions are moist enough. The fungus will start its trail of destruction when it gets to the inner tissues.

The infected site will begin to change to pale yellow. Without urgent treatment, the buds will turn into a slimy mass and eventually fall off.

But botrytis doesn’t only attack the buds. Virtually every part of the plant can be affected by this invasive fungus. You may notice the leaves turning yellowish and burnt. This is because the mold has attacked the inner tissues of your marijuana leaves and is inhibiting chlorophyll production.

What Are The Symptoms Of Bud Rot?

Discoloration of the bud and leaves is the tell-tale sign of bud rot invasion. Depending on the observer, the discolored patches can range from gray to brown.

However, the following are some of the common symptoms of botrytis in cannabis;

  • Mushy, grayish discoloration of the buds and stems
  • Browning of the buds, which indicates progressive rotting
  • Grayish-brown calyces
  • Black spots that can vary in size from small dots to huge patches
  • Yellowing, burning, and wilting of the leaves
  • Browning, drying, or curling of the leaves
  • The purple or darker coloration on the leaves
  • Leaf spotting
  • Abnormal or deformed leaf growth
  • Visible signs of mold, especially around the flower
  • A white, fluffy appearance on the buds

It’s important to note that these symptoms will not appear immediately. Expectedly, the first symptoms will emerge on the initial site of infection. The targeted buds will turn into a mushy grayish color before the disease begins discoloring the leaves. 

A Comprehensive Guide about the Bud Rot Fungus in Cannabis Plant 3

Photo Credit: istock

Is Bud Rot More Of An Outdoor Or Indoor Problem?

Cannabis bud rot can affect both outdoor and indoor plants. However, outdoor growers should be warier of this infectious disease. That’s for the simple reason that it’s difficult to control the outdoor environment.

Weather elements like precipitation and morning dew are almost impossible to avoid outdoors. The implication is that your plants can easily become saturated day and night.

Bud rot is a massive problem for outdoor growers in areas prone to high humidity, such as coastal strips. And as already mentioned, it only gets worse if you’re growing marijuana strains known to produce dense foliage.

How to Prevent Bud Rot

Bud rot can be extremely challenging to treat if discovered late. Therefore, your best bet is to prevent this disease from occurring in the first place.

  • First, invest in cannabis species that do not grow into dense foliage. Such strains are especially recommended if you live in regions that experience consistently high humidity levels throughout the year.
  • The next step is to take care of spacing. Cannabis seedlings are better planted at least 6 feet (1.8 meters) apart. This ensures the plants don’t overlap when fully grown, which would interfere with air circulation. And if the plants somewhat develop extensive canopies, you can always prune off unwanted twigs to enhance unrestricted airflow.
  • Most importantly, implement the ideal cannabis growing conditions, paying particular attention to humidity and temperature. Marijuana thrives under humid conditions between 40 and 50% and within a temperature range of 68 to 77 degrees Fahrenheit.

Wrap Up

Botrytis is a leading cause of cannabis crop failure worldwide. That’s because the disease is commonly misunderstood for other normal fungal infections. We hope you can use this article as a guide to keeping your marijuana farm botrytis-free.