Ascochyta blight of Chickpea

This disease is worldwide in distribution, first described in India by Butler in 1911 and occurs in epidemic forms in Punjab and Jammu.

Etiology

Causal organisum : Ascochyta robiei (Pass.) Labr.

            The conidia are oval to oblong, one to two celled, thin walled and hyaline, but pinkish in mass and measuring 9-20 x 3-6µ. They germinate in water with long germ tubes.

Disease cycle

            The fungus survives for some time in the host tissue, both in the form of pycnidia and peridia and perithecia, it is seed borne both internally and externally. Secondary spread is mainly through air borne inoculums.

Symptoms

• Round spot with brown margin on leaf, stem and pod
• These spots girdle the stem
• Centre of spot numerous minute black dots arranged in concentric zones occur

    Symptoms on leaves                  Symptoms on pods                       Healthy and infected seeds

 Epidemiology

            Night temperatures (10 ⁰C), day temperatures (20 ⁰C) and rain accompanied by cloudy days and excessive canopy favours the disease spread.