Home ​​​​>​​​​ Knowledge Center​​​​

Botrytis cinerea infiltrates plants through soft tissue or wounds, spreading rapidly and affecting any part of the plant, including leaves, stems, flowers, and fruit. Initial symptoms often include tissue darkening and softening, eventually leading to the appearance of gray or white fuzz as the spores develop. If left untreated, gray mold will cause plants to shrivel, dry out, and rot.

When it comes to indoor or greenhouse diseases, preventing botrytis is often much simpler and more cost effective than treatment. By the time symptoms become apparent, the disease has already taken hold, drastically reducing the efficacy of treatment methods. Additionally, there are currently no proven non-fungicidal remedies for gray mold.

In order to develop spores, botrytis requires specific climate conditions, including relatively cool temperatures and high levels of humidity. When the conditions are right, spores begin to develop. These are easily carried by wind, transported by people or thrown around by splashing water, making it very difficult to control their spread.

Once relocated, the spores need to germinate and infiltrate the plant in order to do any damage. Germination is only possible where there is free water, meaning a wet surface. The key to preventing botrytis is to eliminate these favorable conditions. Successful prevention involves combining multiple greenhouse climate control methods to reduce humidity and moisture. Implementing a mix of strategies is the most reliable approach for growers.

Botrytis spores need free water to germinate, so keeping plant surfaces dry is crucial. Proper irrigation techniques, such as watering directly into the soil and avoiding wetting the leaves, can significantly reduce water presence. It's best to irrigate in the morning so that any excess moisture evaporates during daylight.

Humidity is one of the key drivers of botrytis development. Plants constantly transpire, adding moisture to the air. When humidity builds up, condensation can form on cold surfaces like leaves, creating the perfect environment for fungal spores to thrive. Utilizing dehumidifiers and maintaining lower relative humidity levels can help prevent condensation and reduce the risk of fungal outbreaks.

In a crowded ecosystem, with dense foliage, water vapor has a hard time dispersing, creating pockets of very high humidity surrounding the plants. These pockets are known as boundary layers. Spreading out the placement of plants will allow more air to flow through the canopy, reducing humidity build-up.

Pruning overgrown plants may also help in creating a less crowded environment. It’s also important to disinfect equipment between plants to avoid spreading spores.

Another way to reduce humidity and improve plant health is by incorporating air circulation. Any movement of air can help in dispersing the boundary layers. Proper air circulation helps maintain a uniform climate in your greenhouse, preventing localized humidity pockets where botrytis can develop. Implementing a continuous air circulation system can help reduce moisture build-up, keeping conditions less favorable for the fungus.

Debris like fallen leaves or fruit can decompose and harbor botrytis spores. Keeping the soil bed clean and free of debris minimizes the chances of spore development. Cleanliness is especially important as spores can be spread through splashing water, further infecting nearby plants.

Botrytis often enters plants through wounds. When tending to your crops, handle plants carefully to avoid creating entry points for the fungus. Gentle handling reduces the risk of infection.

Whether from sunlight or artificial light, proper radiation helps evaporate excess water, minimizing moisture where spores could develop. Good lighting also supports healthy plant metabolism and photosynthesis, strengthening the plant’s natural defenses against diseases.

Neem oil acts as a natural fungicide that can help reduce the concentration of fungal spores. Applying neem oil regularly, as a preemptive measure, can drastically reduce the chances of a botrytis breakout. It also provides the added benefit of acting as a natural pesticide, decreasing harmful insect populations in the process. 

To make your own neem oil spray, mix 1-5 milliliters of neem oil with 1-2 milliliters of liquid soap in 1 liter of water. Neem oil is safe for humans and is available at most health stores.

If plants become infected, removing them as quickly as possible is crucial to preventing further spread. Infected plants should be disposed of outside the greenhouse to avoid contaminating other crops. Avoid composting infected plants, as botrytis spores can remain active and lead to future outbreaks.

Do not hesitate to ask your questions to our specialist using the form. We will respond to your questions as soon as possible.