Colletotrichum truncatum

Systematic position and type of pathogen: Colletotrichum truncatum belongs to the kingdom Fungi, phylum Ascomycota. It is a major fungal pathogen known to cause anthracnose in a wide range of legumes. The pathogen is characterized by the production of acervuli containing dark, stiff bristles, which facilitate its identification in laboratory conditions.

Diseases caused and host crops: The primary disease associated with this fungus is soybean anthracnose. It significantly affects the development of various leguminous crops, including dry beans, chickpeas, and lentils. The pathogen targets the stems, leaves, pods, and seeds, often leading to severe yield losses in infected regions.

Biology and life cycle: The fungus survives the winter as mycelium or as structures called sclerotia in crop residues and infected seeds. Under warm and humid conditions, it produces masses of conidia that are splashed by rainfall or spread by wind to healthy plant parts. These conidia germinate and penetrate the host tissue, initiating secondary infections that can cycle repeatedly throughout the growing season.

Conditions for development and harmfulness: The development of Colletotrichum truncatum is highly dependent on high humidity and temperatures ranging from 20°C to 30°C. Harmfulness is manifested in stunted growth, pod rot, and seed discoloration. In severe cases, the entire plant may wither prematurely, leading to substantial reductions in seed quality and market value.

Protection and control measures: Integrated management is essential to minimize damage:

• Planting disease-free, high-quality seeds.
• Implementing crop rotation with non-leguminous hosts for at least 2–3 years.
• Managing crop debris through deep tillage to bury infected tissues.
• Applying foliar fungicides specifically targeting Colletotrichum species during the critical growth stages.