Ascochyta blight

Ascochyta blight is a major fungal disease caused by the pathogen Didymella rabiei. This disease is particularly devastating for chickpeas, although it also affects lentil and field pea crops. It is recognized as one of the most significant limiting factors for global pulse production in many regions.

The infection manifests as lesions on all aerial parts of the plant, including leaves, stems, and pods. These spots are typically circular or elongated with a dark margin. As the disease progresses, small dark fruiting bodies known as pycnidia develop within the lesions, which are characteristic diagnostic features of this pathogen.

The development of the disease is highly dependent on environmental conditions, particularly cool to moderate temperatures and high humidity. Frequent rainfall and persistent dew promote the dispersal of fungal spores through rain splashes and wind. In such conditions, the disease can spread rapidly across a field, leading to severe outbreaks.

The damage caused by Didymella rabiei is substantial, leading to significant yield losses, reduced grain quality, and potential failure of the crop in favorable years. Infected seeds often fail to germinate, or resulting seedlings may die shortly after emergence due to the presence of the fungus on the seed coat.

Effective management requires a multi-faceted approach to reduce the inoculum load and protect the crop. Recommended strategies include:

• Planting certified, disease-free seed treated with systemic fungicides.
• Rotating crops with at least a 3–4 year gap between susceptible legumes.
• Application of foliar fungicides during the vegetative growth stage if weather conditions favor the disease.
• Destroying or deeply burying infected crop residues to prevent overwintering of the fungus.
• Growing resistant or tolerant chickpea cultivars suited to local conditions.