Ascochyta blight of lentil

Systematic position and pathogen type: The causal agent of lentil blight is the fungus Ascochyta lentis (teleomorph Didymella lentis). It belongs to the Ascomycota division. This fungal pathogen is highly specific to legumes, particularly lentils, and serves as a major limiting factor in the cultivation of this crop in humid regions.

Diseases and crops: The fungus causes Ascochyta blight, a systemic disease that impacts lentil production globally. All above-ground parts of the lentil plant are susceptible to the pathogen, including leaves, stems, flowers, and developing pods. The infection causes necrotic lesions that impair photosynthesis and lead to significant yield losses and poor seed quality.

Biology and life cycle: The pathogen survives as mycelium or pycnidia in infected crop residue and within contaminated seeds. During the growing season, pycnidia produce conidia that are disseminated by rain splash, wind, or agricultural equipment. The infection process begins when these spores land on susceptible plant tissues under favorable moisture conditions, initiating the disease cycle.

Conditions for development and spread: Ascochyta lentis thrives in cool to moderate temperatures and high humidity. Optimal conditions for spore germination and infection involve prolonged leaf wetness, often associated with rainy weather and overcast skies. If high moisture levels persist, the fungus can spread rapidly across a field, causing severe outbreaks within a short period.

Damage, protection, and control measures: The disease causes significant economic loss, reducing both seed yield and marketability. Management strategies must be proactive:

• Sowing disease-free, certified seeds treated with effective fungicides.
• Implementing crop rotation with non-leguminous crops for at least 3-4 years.
• Deep tillage to bury crop residues and reduce primary inoculum.
• Monitoring fields for early symptoms and applying foliar fungicides as needed.
• Selecting resistant or tolerant lentil cultivars suited for the local climate.