Cylindrocladium leaf spot and stem canker

Cylindrocladium leaf spot and stem canker is a serious fungal disease caused by species within the Cylindrocladium genus (often reclassified under Calonectria). This pathogen acts as both a foliar blight and a stem-infecting fungus, causing significant physiological stress and structural damage to a wide range of host plants, leading to severe yield losses in susceptible agricultural crops.

The host range of this pathogen is extensive, encompassing various woody plants, ornamentals, and key food crops. Among legumes, chickpea is a known host, where the infection can severely damage the vascular system and stem tissue, hindering nutrient uptake. The pathogen is notorious for its ability to persist in soil for prolonged periods, making sanitation and soil management critical components of control.

Symptoms typically begin as small, water-soaked spots on leaves that expand into irregular, dark brown necrotic lesions. As the disease progresses, stem cankers appear near the soil line or along the branches, which can lead to wilting, stunting, or total collapse of the plant. In humid conditions, the presence of white to yellow sporulation can often be observed on the affected necrotic areas.

Development and dissemination of the disease are heavily dependent on high moisture levels and warm temperatures. The fungus produces spores that are easily dispersed by rain splash, irrigation water, and contaminated nursery equipment. High plant density creates a microclimate with high humidity, which significantly accelerates the rate of infection and spread throughout a field or greenhouse.

Management strategies for this pathogen require an integrated approach. Effective measures include the use of disease-free planting material, improving drainage, and maintaining optimal plant spacing to promote airflow. Chemical control using registered fungicides is often necessary during wet seasons to suppress the development of lesions. Regular monitoring and removing symptomatic plant parts are essential to limit the primary source of inoculum.