Alternaria alternata causes leaf and fruit blight in makhana

Makhana (Euryale ferox) is a high-value commodity of nutritional, medicinal and ritualistic significance. North Bihar has occupied a prominent position in terms of both production and productivity of makhana not only in India, but across the globe. Leaf blight disease on makhana was noticed in April 2018, with a severity of 15–20% in a survey of farmers’ ponds in North Bihar. Symptoms of the disease were circular, small, light-brown, necrotic, sunken lesion that later turned into a large, dark, blighted area in the leaves. Blighting of fruits was also noticed during June and July 2018. Blighted fruits were small, distorted and twisted with less seed. Alternaria alternata was identified as the pathogen causing the disease based on morphological and cultural characteristics of the culture maintained on potato dextrose agar from symptomatic leaf and fruit samples. The fungus gave rise to greyish to grey–black colonies with obclavate to obpyriform, catenulate conidia in chains. Conidia consisted of 2–5 horizontal and 0–2 vertical septa and measured 15–60 ´ 5–9 mm in dimension. Molecular confirmation was done by sequence analysis of the internal transcribed spacer (ITS) regions of rDNA using ITS1 and ITS4 primers. Eventually, pathogenicity test inferred that leaf and fruit blight in makhana are due to A. alternata infection