In agriculture, Trichoderma serves as a valuable biofertilizer and biocontrol agent, promoting plant growth by stimulating root development and nutrient uptake, and suppressing soil-borne fungal diseases through competition, antimicrobial activity, mycoparasitism, and inducing plant resistance. Its application improves nutrient use efficiency, enhances plant tolerance to abiotic stresses such as drought, and contributes to sustainable agriculture by reducing dependence on synthetic agrochemicals and improving soil health.
1.Common and Important Trichoderma Species in Agriculture
Although there are hundreds of Trichoderma species, the following are the most common and effective in agricultural microbial preparations:
(1)Trichoderma harzianum: This is the most common and widely used Trichoderma species. It grows rapidly, is highly adaptable, and possesses a comprehensive range of disease control mechanisms, making it a core strain in many commercial biopesticides and biofertilizers.
Key Features: A versatile competitor, possessing diverse abilities such as hyperparasitism, competition, and resistance induction.
(2) Trichoderma viride: Equally renowned as Trichoderma harzianum, this is also a very important biocontrol agent. It is particularly effective in producing antibiotics.
Key Features: It is the primary producer of the famous antibiotic trichoderma, which has direct inhibitory and antibacterial effects on a variety of pathogens.
(3)Trichoderma koningii: This species has a strong ability to dissolve minerals, effectively releasing fixed elements such as phosphorus and potassium in the soil for plant absorption.
Key Features: An excellent soil nutrient activator, it significantly promotes plant growth.
(4)Trichoderma spp./Trichoderma acanthosporum: Excellent control of root rot and damping-off caused by Rhizoctonia solani.
Key Features: Specific effectiveness against Rhizoctonia solani.
(5)Trichoderma longibrachiata: Strong root colonization ability, allowing for a successful symbiotic relationship with plant roots.
Key Features: Excellent root colonizer, providing long-term root protection.
(6)Trichoderma aureum: Also a common biocontrol agent, it produces a variety of cell wall-degrading enzymes and antibiotics.
2.The Core Role of Trichoderma in Agriculture (Detailed Mechanism)
The roles of Trichoderma can be summarized into three main areas: “defense,” “enhancement,” and “improvement.”
Role 1: Biological Control (Plant’s “Master Defense”)
This is the core function of Trichoderma. They protect plants through a variety of synergistic mechanisms:
(1)Competition:
Competition for space and nutrients: Trichoderma grows extremely rapidly, rapidly occupying ecological niches such as the rhizosphere and phyllosphere of plants, depriving pathogens of the “territory” and nutrients they need to survive, leaving them with no place to stand.
(2) Hyperparasitism:
Direct Attack: Trichoderma can recognize pathogens, entangle and penetrate them with their hyphae, and secrete enzymes such as chitinase and glucanase. These enzymes “dissolve” the pathogen’s cell wall, absorb nutrients, and ultimately kill it. This process is like “fungus eating fungus.”
(3)Antibiotic Effect:
Chemical Weapons: Trichoderma can produce a variety of antimicrobial substances, such as trichoderma, gliomycin, and chlorophyll. These substances can inhibit or directly kill surrounding pathogens.
(4) Inducing Systemic Resistance:
“Vaccinating Plants”: When Trichoderma symbiotically coexists with plant roots, it “awakens” the plant’s own immune system, putting it in a state of “alert.” When the actual pathogen attacks, the plant can initiate a more rapid and robust defense response, producing defensive substances to resist the invasion.
Diseases Controlled: It is effective against a variety of soil-borne and airborne diseases, including wilt caused by Fusarium wilt, damping-off caused by Pythium, damping-off caused by Rhizoctonia, and gray mold caused by Botrytis cinerea.
Function 2: Promotes Plant Growth (a “growth booster”)
(1) Improves Nutrient Absorption:
Phosphorus and Potassium Solubilization: Trichoderma fungi secrete organic acids and enzymes, releasing phosphorus and potassium that are fixed in the soil and inaccessible to plants, converting them into absorbable forms
Enhanced Iron Absorption: They produce siderophores, efficiently chelating iron for plant use.
Minor Nitrogen Fixation: Some strains have the ability to fix nitrogen.
(2)Plant Hormone Production: Trichoderma fungi can synthesize or stimulate the production of auxins (such as indoleacetic acid), directly stimulating root development, making plants stronger and increasing yields.
(3)Enhanced Stress Resistance: Plants treated with Trichoderma are more tolerant to abiotic stresses such as drought, salinity, and heavy metals.
Case Study: Cucumber – The Ultimate Solution for Continuous Cropping Problems
Application Background: Continuous cropping of cucumbers can lead to soil degradation, increased disease infestation, and poor growth, a phenomenon known as “continuous cropping problem.”
Application Method: Apply Trichoderma fungus to the roots or holes at planting time.
Observed Effects:
Overcoming Autotoxicity: Trichoderma accelerates the breakdown of harmful autotoxic substances secreted by cucumber roots, improving the rhizosphere microecology.
Growth-Promoting Effect: Vigorous plant growth, shortened internodes, and extended fruit-bearing period. Straighter fruit stems and a higher marketable fruit yield are achieved.
Overall Benefits: While preventing and controlling soil-borne diseases (such as wilt), this method significantly increases yield (10%-20%) and improves quality, providing a comprehensive solution to overcoming continuous cropping problems.
Function 3: Soil Improvement (Soil’s “Eco-Engineer”)
(1)Decomposition of Organic Matter: As saprophytes, they can break down organic residues like straw in the soil, accelerating nutrient recycling.
(2) Improvement of Soil Structure: The mycelial network weaves soil particles together, forming a granular structure that increases soil porosity, improving aeration and water retention.
(3)Pollutant Degradation: Certain strains can degrade pesticide residues and repair soil.
3.Specific Applications of Trichoderma in Agriculture
Based on the above mechanisms, Trichoderma is primarily used in agricultural production through the following methods:
(1)Seed TreatmentMethod: Mix or soak seeds with a Trichoderma formulation (such as a wettable powder).
Purpose: Establish a protective barrier for seeds before germination, preventing soilborne pathogens from infecting young roots and shoots, and effectively preventing seedling diseases (such as damping-off and damping-off).
(2)Seedbed/Seedling Media Treatment
Method: Mix Trichoderma granules or powder with seedling media (such as nutrient soil) or apply directly to the seedbed.
Purpose: Provide continuous protection for the entire root system of the seedlings, cultivating disease-free and strong seedlings.
(3)Soil Treatment
Method:
Hole application: Apply the Trichoderma formulation directly to the planting hole during transplanting.
Furrow application: Apply the formulation in furrows between crop rows.
Root irrigation/drip irrigation: Apply the liquid formulation to the roots along with the irrigation water. Purpose: Directly colonize the crop rhizosphere to continuously prevent and control soil-borne diseases (such as wilt and root rot) and activate rhizosphere soil nutrients.
(4) Composting
Method: Introduce Trichoderma agents during the composting process.
Purpose: Leverage the powerful decomposition capabilities of Trichoderma to accelerate the decomposition of organic waste such as straw and livestock manure, improve the quality and efficiency of compost, and inhibit harmful bacteria in the compost.
(5) Postharvest Treatment
Method: Prepare the Trichoderma agent into a suspension and spray it on the surface of harvested fruit.
Purpose: Leverage its antagonistic effects to prevent and mitigate storage diseases such as gray mold, thereby extending the shelf life of agricultural products.
In summary, Trichoderma fungi are multifunctional beneficial agricultural microorganisms. Through their integrated efforts of “disease prevention, growth promotion, and soil improvement,” they provide a powerful tool for achieving green, organic, and sustainable agricultural production, serving as a vital bridge between ecological balance and high agricultural yields.More details could chick here.