The Trichoderma Threat in Mushroom Cultivation: How to Handle It


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Growing mushrooms, whether commercially or for personal use, is an interesting and rewarding venture. However, one of the biggest challenges that mushroom growers face is contamination. Among the many possible contaminants, Trichoderma, often referred to as green mold, is arguably the most common and destructive. This ubiquitous fungus is not only hard to eliminate but can also rapidly colonize and ruin mushroom substrate before the desired mushrooms have a chance to grow. This article will delve into understanding Trichoderma, its impact on mushroom growing, and effective prevention and control strategies.

What is Trichoderma?

Trichoderma is a genus of fungi that includes numerous species, many of which are highly aggressive saprophytes. It thrives in various environments and is especially prevalent in soil and decaying organic matter. Certain species of Trichoderma are beneficial and used in biocontrol applications to combat other plant pathogens. However, for mushroom cultivators, Trichoderma represents a menace, often appearing as a vibrant green mold that competes with and overtakes the desired mushroom species.

Trichoderma in mushroom cultivation

How Does Trichoderma Impact Mushroom Cultivation?

Trichoderma is an exceptionally fast grower. When it contaminates a mushroom culture, it quickly colonizes the substrate, outcompeting the mushroom mycelium for nutrients. It can cause significant crop losses and, in severe cases, can wipe out an entire crop.

In addition, Trichoderma produces enzymes that degrade the cell walls of other fungi, including the mushroom mycelium, inhibiting their growth or killing them. Once a Trichoderma contamination becomes established, it’s incredibly difficult to remove or control, particularly if the growing conditions are conducive to its proliferation.

Preventing Trichoderma Contamination

  1. Sterilization: Sterilization is the first line of defense against Trichoderma. All substrates should be sterilized properly before inoculation to eliminate any Trichoderma spores. Autoclaving, steam pasteurization, or using a pressure cooker are popular methods.
  2. Cleanliness: Maintaining a clean environment is crucial to prevent contamination. This includes regularly cleaning the growing room, tools, and equipment, and practicing personal hygiene.
  3. Proper Airflow: Ensuring proper ventilation can reduce the chances of Trichoderma contamination. Stagnant air can lead to high humidity and moisture, which promotes the growth of Trichoderma.
  4. Quality Spores and spawn: Always source your mushroom spores or spawn from reputable suppliers. This reduces the chance of introducing Trichoderma right from the start. One way to ensure quality spawn in to make your own sterilized grain jars.

Handling Trichoderma Contamination

Despite the best preventive measures, Trichoderma contamination may still occur. Here’s how to handle it:

  1. Early Detection: Regularly inspect your mushrooms and substrate for any signs of contamination. Early detection and action can prevent the spread of Trichoderma to other parts of your cultivation.
  2. Isolation: If you notice any contaminated substrates, isolate them immediately to prevent the spores from spreading.
  3. Removal: Remove and properly dispose of any contaminated substrate. It’s not advisable to try and save a Trichoderma-contaminated substrate, as the risk of further contamination is high.

Tools for Sterile Mushroom Growing

  • 70% Isopropyl Alcohol. 70 percent Isopropyl alcohol is preferred because it dissolves slower than 90% isopropyl alcohol. This gives you more time to efficiently clean your growing area.
  • Nitrile latex gloves. Gloves are important when it comes to mushroom cultivation because we carry bacteria and other contaminations with us everywhere we go throughout the day. Our main goal is to reduce contamination and now introduce it. Nitrile gloves are preferred when dealing with mushrooms because they do not contain powder. The powder is messy and can introduce unwanted results.
  • Stainless steel dissection kit. Stainless steel dissection kits are washable and can be disinfected fairly easily via isopropyl alcohol or flame sterilization.
  • Stainless steel bench. Stainless steel is easy to clean and can ensure a sterile working surface for mycology work.
  • Face masks. Face masks can reduce the amount of contaminates that could possibly be introduced to your working environment.


Trichoderma contamination can be a daunting challenge in mushroom cultivation, but understanding its nature and applying robust preventative measures can significantly reduce the risks. Regular monitoring and rapid response to any signs of contamination will also keep your cultivation environment healthy. While this process requires a keen eye and a proactive approach, the rewards of successfully growing your own mushrooms are well worth the effort.

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