Cercospora cajani, Cercospora indica ,Cercospora instabilis

Fungal Disease

Cercospora cajani, Cercospora indica ,Cercospora instabilis

Fungal Disease

Introduction and Distribution
Cercospora leaf spot is a significant fungal disease of redgram, widely distributed in regions such as India, Bangladesh, Kenya, Nigeria, Sri Lanka, and Venezuela. It thrives in humid areas and poses a severe threat to redgram cultivation.

Economic Importance
The disease can cause yield losses of up to 85%, particularly in eastern Africa. Defoliation before flowering and podding results in significant production losses, making the disease a critical concern for farmers in affected regions.

Epidemiology

• Favored by cool temperatures (around 25°C) and high humidity.
• Commonly occurs during the flowering and podding stages of the crop.
• Cyclonic rains in southern and northeastern India often lead to sudden outbreaks.
• Long-duration and perennial redgram varieties are more susceptible.

Symptoms

• Early Signs: Small, circular to irregular necrotic spots appear on older leaves.
• Progression: Lesions expand and coalesce, causing leaf blight and defoliation. Severe outbreaks may lead to tip dieback in young branches.
• Regional Differences: Indian isolates produce fluffy mycelial growth on lesions, whereas African isolates form concentric zonations on lesions.

Proper monitoring and timely management are essential to mitigate the disease's impact, especially in high-risk humid regions.