WHAT IS IT?
Trichoderma is a genus of soil-dwelling fungi found worldwide. They are fast-growing, highly adaptable fungi that form symbiotic relationships with plant roots making them ideal for fungicidal use in agricultural settings. Some strains of Trichoderma have been isolated to use those traits to the advantage of gardeners and growers.
Trichoderma harzianum, strain T-22 is a hybrid strain developed to enhance certain characteristics of its parent strains. These enhancements in disease resistance, environmental tolerance and crop compatibility made T. harzianum one of the first biofungicides on the market. It has proven to be useful in controlling common soil-borne diseases like Fusarium, Pythium and Rhizoctonia on a wide range of crops including corn, soybeans, potatoes, tomatoes and cotton.
HOW DOES IT WORK?
T. harzianum, strain T-22 utilizes several methods to suppress fungal diseases. First, it forms a physical bond with the root system of the plants, establishing itself in the rhizosphere (root zone) and thereby preventing other pathogens from colonizing the soil. This bond and continual growth of the T. harzianum throughout the root system forms a physical barrier to plant pathogens. T-22 also feeds on excess nutrient content left unused by the root system, which would provide a food source for incoming pathogens otherwise. Keeping that in mind, T. harzianum does not interfere with mycorrhizae activity or Rhizobium (a common nitrogen-fixer).
Secondly, T-22 releases chitinases, specific enzymes that denature chitin, to break down the cell wall of fungal pathogens in the soil. The holes in the cell wall created by the enzymes turn the pathogenic fungi into prey for other soil microorganisms. The combination of these methods allows T. harzianum to displace other organisms from the soil and the root system to develop additional biomass useful in increasing plant yields.
- Trichoderma Taxonomy & Uses (Cornell University College of Agricultural & Life Sciences)
- Trichoderma for Control of Soil Pathogens (University of Connecticut Dept. of Plant Science & Landscape Architecture)