Botrytis Cinerea: How to Prevent and Control It

Ed Wike
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Botrytis Cinerea Overview

Botrytis Cinerea, or gray mold, is a fungus that thrives in cool, wet conditions when temperatures exceed 50°F. Fresh vegetables that are handled in a humid environment have the best conditions for gray mold to grow. There is nothing you can specifically do to control this fungus. What you can do is control your airflow, air temperature, and humidity to slow the spread. To control Botrytis Cinerea you need to have good airflow within your crops. Make sure that your crops have good air circulation from the outside. You may have to open a door or flip open some poly covers to let air in. This could provide a cooling effect in the greenhouse to slow the spread. Turning fans on during the heat of the day could help as well. Keep in mind that this could effect the humidity in the greenhouse as well and higher humidity will promote Botrytis Cinerea. Maintaining a higher humidity between 40% to 50% could help. Keeping your air temperature above 50°F is also one way to help slow the conflict of Botrytis Cinerea. By keeping the growth area at 60°F to 70°F you will slow the spread of Botrytis Cinerea and other fungi and bacteria that thrive in cool, wet conditions.

What Is Botrytis Cinerea?

If you’ve ever experienced this plant disease before, you already know how destructive the fungus can be, and you also know how difficult it can be to bring under control. This plant pathogen, also known as gray mold, affects a wide range of plants and fruits (such as strawberry, vine, cherry, cranberry, plum, and grapes).

The primary reason why Botrytis cinerea is so destructive is the ability it has to invade plant roots and quickly travel into the stem and upward into the rest of the plant. Once there, it begins to produce toxins and wilt the plant in various ways. Some mold species merely cause a loss of nutrients and moisture in the area of infection, but others kill the plant instantly.

How It Affects Plants

Botrytis cinerea fungus affects the leaves and twigs fatally. Over time, portions of affected leaves tend to drop, and the affected area looks like there’s been an explosion of holes, with a brown or black discoloration throughout. The fungus will rapidly spread into the rest of the plant and can easily destroy it within a couple of days.

Life Cycle Of Botrytis Cinerea

Botrytis Cinerea is a disease that can kill strawberries and other berries, and pole beans and other vegetables and herbs. It can spread rapidly and, when it does, it can result in the death of entire crops. It is also sometimes called grey mold or gray mold.

Botrytis Cinerea is a fungus. It is a type of Fusarium, a category of fungi that are widespread and prolific. The Botrytis Cinerea category of Fusarium is among the deadliest because it dehydrates the plant that it infects as it grows. The first visible sign of a Botrytis Cinerea infection is when the leaves of a plant begin to wilt. The leaves will develop tan patches and curl. In severe cases the plant's stems will become brittle and snap easily.

Botrytis Cinerea only affects plants that have a long growing season. The fungi produces a spore which can survive mild temperatures. When temperatures rise, the motes can germinate and then infect the plants. It can cause devastating loss if you are growing strawberries, tomatoes, beans, cucumbers, melons, peppers, and herbs.

Symptoms of Botrytis Cinerea

Botrytis cinerea is a fungal disease that attacks many types of plants and flowers. The most visible sign of this disease is a gray mold that grows on the surface of the plant tissue.

When the mold grows in large amounts it can make the plant tissue gummy and slimy, and the plant tissue can eventually dry up and die.

Most commonly seen in greenhouses but can occur under any warm, moist conditions, botrytis strikes a wide range of fruits and vegetables. It causes many gardeners to lose a lot of their most prized plants.

Botrytis is present in most areas where plants are grown. The spores are in the soil or on healthy plants and can be carried by water, insects, or other organisms. The spores thrive in moist, shady places until they find a host plant to feed on.

When plants are stressed by transplanting, weather conditions, watering, feeding, diseases, or pests, the natural immunity that protects them has been compromised. This is what causes botrytis spores to start growing and feeding on the weakened plant.

Asian Lady Bugs, flying moths and other beneficial insects are actually feeding on the mold as it grows. When other things are introduced to kill the mold, they kill anything that is feeding on it.

Early Botrytis Detection

Botrytis thrives on poorly colored, mildewy, stale, wet flowers. They spread across the top of the plant in a very thin layer of soft green mold that is almost unnoticeable. You have to look hard at the tissue around the flowers, under the leaves, and at the base of the stem to see signs of the damping off pathogen.

Assuming you do see the soft green mold, you must catch the disease before it kills the plant. Consistent in-grow lighting and humidity, along with supplemental oxygen to the affected plants should stop the Botrytis infection before the disease can take hold.

There is no cure for this pathogen. Once it has taken hold of the plants, you have to toss the plants, immediately. This is not a disease that you can treat or control. If it is not a preemptive strike that prevents the bloom from planting, it is best to toss.

Later Botrytis Progression

Botrytis Cinerea is a potentially devastating fungal disease that affects a wide variety of plants. While the causal organism is present in most garden soils, it's a problem only when circumstances are appropriate for disease development.

Symptoms include a gray brown discoloration of foliage with a soft, downy growth on diseased tissue and fruit. When temperatures are moderate, the disease progresses slowly. However, vulnerable plants may collapse completely under prolonged, heavy infections.

There are a number of preventive measures that gardeners can take to help prevent the buildup of fungus in their gardens. These include:

  • Planting disease-resistant strains
  • Removing any weeds that may harbor the primary organism responsible for the disease
  • Keeping your garden free of any dead plant material and being careful to not over-water your plants
  • Removing any diseased plant material immediately
  • Mulching with a good, organic material
  • Adding a layer of gravel to your garden area and making sure it stays shallow
  • Avoiding planting susceptible crops in close proximity

Understanding The Noble Rot

Botrytis cinerea (or simply Botrytis) is a plant fungus which is commonly known as “noble rot”. Many red wine drinkers will be pleased to know that this species of fungus causes grapes and other grape products to turn a deep purple or even black color; thus, the coloring used to make some red wines.

Botrytis is also notorious for developing on the bruised sides of fruits and vegetables and can cause these fruits and vegetables to turn rotten quickly. This is why it is essential and important to not handle and handle fruits or vegetables with dirty or bare hands.

This plant fungus can also develop on the aging flowers of your plants, as well as on the leaves themselves.

Don’t fret. The spores of this disease are not dangerous and are not particularly toxic for humans, animals, or plants.

However, you don’t want to let it spread throughout your garden or plants. There are several different methods or methods to use to prevent and control them. Botrytis thrives in cool, wet environments and is more likely to develop in places where humidity is high, such as a wet basement.

Controlling Botrytis Cinerea

(Die Back)

While botrytis cinerea is mostly a nuisance on ornamental plants, it can also lead to significant losses on some vegetable crops. In addition to the considerations listed above, the following practices can help minimize the risk of botrytis cinerea outbreaks:

Proper airflow and watering system – Make sure the system can remove excess moisture from the air and roots and that there are not any puddles in the greenhouse.

Remove any unused or unneeded plant material from the greenhouse as soon as possible.

Promptly remove any dead plants or plant parts in areas underneath plants that are inclined to produce a lot of decaying plant material such as Tomatoes.

Proper sanitation – Make sure the floor of the greenhouse is free of all plant materials and any other debris. Good housekeeping, including keeping the floor swept clean, will help prevent the spread of botrytis cinerea.

Plant materials that are susceptible to this disease should be held in a separate area of the greenhouse to ensure that they do not come in contact with other susceptible plant material.

Pruning plants in proper intervals can also help keep this disease under control.

Preventing Botrytis Cinerea

To grow a lot of flowers, you want the environment inside your grow room to be as close to optimal as possible. Since it is difficult to control the temperature and humidity in a given room, the best thing you can do is give your plants the most light and space that you can afford.

Providing your plants with all the light they can take is the best, no matter what type of room you use. But if you’re growing in a tent, you have to be careful to avoid over-heating the room.

The easiest way to manage this is to live close to the plants. When you are physically there, you can monitor them and react to changing conditions much more quickly during the day.

When you are not at home, you can install an environmental monitoring system. A good system will alert you to conditions that might cause problems for your plants.

In any case, an oscillating or spinning fan will help you to lower the temperature in your grow room. A constant flow of fresh air is also a good idea. It prevents mold as well.

Preventing Botrytis Cinerea In Greenhouses or Indoor Grows

A few simple steps can help prevent and contain this infectious and destructive disease. This post will explain what Botrytis Cinerea is. Next, we'll cover a few preventative measures that you can take to significantly slow down the growth in your indoor garden or greenhouse.

Botrytis Cinerea is one of the biggest problems in the cannabis industry. Fortunately, you can take action to fight this dreaded fungus. In fact, it's quite easy. The key is to reduce the amount of fungus spores in the air. Obviously, you don't want your garden to have more than a few spores circulating.

The fungus isn't exactly that hard to see. In fact, you can spot the powdery white patch it leaves behind. If you see this or if your plant is already infected, these steps will help you keep it under control.

What To Do When Prevention Fails

If prevention fails, and you must face the dreaded Botrytis cinerea in your garden, be certain to isolate the plant. Do not let it contaminate healthy plants.

Botrytis blight is one of many garden problems that is caused by living organisms. In this case, the organism is a fungus. Just as certain minimalist gardening techniques can be used to address a wide array of garden pests, a similar strategy can be used to tackle blights.

Here are a few practices that can be employed to help control Botrytis:

  • Avoid watering at night.
  • Provide adequate airflow.
  • Eliminate periods of excess moisture.
  • Avoid working around the plant when it is wet.
  • Rotate crops.
  • Deeply mulch the soil to help keep moisture at healthy levels.
  • Erect barriers to limit the spread of spores.
  • Practice crop rotation.
  • Harvest botrytis-infected produce immediately.

Organic Treatments

Put in place a program of cultural practices designed to prevent infected buds, shoots, leaves, or grapes from maturing into the grapes that will be harvested in the fall. This includes keeping vines healthy so that they are not as susceptible to B. cinerea, which often flourishes in stressed areas of vines. Vineyard managers usually focus their control schemes on the buds, shoots, and leaves of grapevines. They surgically remove infected tissue and seal wounds with root repair materials such as grafting wax or other materials. Used properly, these substances will dry in place and not need removal.

Put in place cultural controls such as proper pruning, training, and plant spacing to make vines more resistant to infection. The most important practice in this regard is to prune vines properly, allowing good sunlight and airflow through the vines.

Educate vineyard managers and growers on how to recognize the disease and, most importantly, when treatment is necessary. This can provide control if growers take action before the disease becomes a serious problem, or it will allow vineyard managers to make their informed decision about whether or not to take action during the season.

Mycorrhizal and Bacterial Treatments

Botrytis cinerea (also fungal initials) is a fungus that is both a risk and a benefit for the grower.

If caught early, it can inhibit harvestable yields. However, it’s a beneficial, symbiotic fungus that is necessary for healthy root development.

To prevent Botrytis infection in your garden, regularly water your garden with a nutritional supplement. This will seed your garden with mycorrhizal fungi, and this will help prevent a Botrytis infection.

Botrytis can be controlled by applying Bacillus subtilis (aka a beneficial bacterium) or Mycostop (a beneficial fungus). Interestingly, when you use both Bacillus (a beneficial bacterium) and Mycostop (a beneficial fungi) you get even better results.

Important: Do not use antibiotics or fungicides when you are attempting to tackle a Botrytis infection with beneficial bacteria or fungi.

The goal is to get the beneficial fungi in so that they can start to work symbiotically with your plants. This symbiotic relationship will prevent the spores from germinating. So getting the beneficial fungi and bacteria into your garden is essential.

Frequently Asked Questions

What is Botrytis cinerea?

Botrytis is a fungus that can enter tobacco plants that have been damaged.

Fungus that can enter tobacco plants that have been damaged. Botrytis can grow inside the flue-cured tobacco leaves.

Can grow inside the flue-cured tobacco leaves. The fungus can infect the flue-cured tobacco in the field or after it has been dried.

Can infect the flue-cured tobacco in the field or after it has been dried. Botrytis in flue-cured tobacco spreads quickly in moist, warm conditions and can compromise entire curing barns.


Workers, manufacturers and retailers may suffer from breathing problems and lung infections.

May suffer from breathing problems and lung infections. Residents living in the nearby areas may suffer from respiratory problems and eye infections.

May suffer from respiratory problems and eye infections. Consumers may suffer from nausea, dizziness and dry cough.


If you experience a lot of dust in the air and see signs that your eyes are irritated – rinse your eyes with water.

Your eyes with water. If the symptoms are severe, please consult your doctor .

Q: Is botrytis cinerea dangerous to humans?

Botrytis cinerea is also known as gray mold or grey mold and can harm humans. The fungus was once thought to only threaten grapes in Europe. Since then, researchers have found that the mold can spread to a variety of fruits and vegetables. This disease is most commonly found in greenhouses used to cultivate flowers. If left unchecked, gray mold can cause fatal injury to the lungs of both humans and animals.

Q: Is botrytis cinerea a human or animal disease?

Botrytis cinerea is commonly found in soils that have been over-fertilized. Infected areas are oftentimes wet and humid. This creates an ideal environment for the mold to cause infections in both plants and humans.

Although the mold is considered to be a human health hazard, it does not cause issues for all people. Some individuals will experience mild discomfort such as nasal congestion, eye irritation, or a sore throat.

Gray mold, which has the ability to taint cannabis yields, is more likely to be dangerous to other mammals than humans.