ABSTRACT
Euryale ferox Salisb (also known as fox nut, foxnut, makhana, or gorgon plant) is one of the most valuable cash aquatic fruit grown in thousands of fresh water stagnant pools (both natural and man-made) of Northern and Eastern Asia, Europe, America, etc. and is very common in the freshwater habitats of Northern, Eastern and Western India. In India, it is grown in the various tracts of N.E. Assam, Tripura, West Bengal, Orissa, Bihar, and Meghalay, different parts in MP and UP and in Alwar (Rajasthan). North Bihar and lower Assam are probably the only states in India where the plant is cultivated for commercial purpose along with Nelumbium, Trapa species and fish (Ahmad and Singh, 1991, 1997; Datta Munshi, et al., 1991; Dehadrai, 1994; Jha, 2000). For geographical and climatic reasons Bihar is the heaven for Makhana Production. The cultivation of the crop is confined to Dharbhanga, Motihari, Madhubani, Samastipur, Sitamarhi, Saharsa, Supaul, Araria, Kishanganj, Katihar and Purnea districts of Bihar. Makhana is cultivated in more than 2000 ha in Darbhanga and Madhubani districts. Around 75% of the total Makhana production comes from Bihar Swetlands. Approximately 2000 tons of popped makhana worth Rs. 100 million are exported outside north Bihar (Thakur, 2005). Makhana is valued for its nutritional, medicinal and ritualistic significance also. In north Bihar, the seed is consumed in popped form, but in Manipur, other parts (leaves and stalks) are consumed as vegetables. Seeds are also used in many dishes of India. It is highly estimated for its spermatogenic and aphrodisiac properties and is used in rheumatic disorders. Makhana is superior to dry fruits such as almonds, walnut, coconut and cashew nut in term of sugar, protein, ascorbic acid and phenol content. It has 80% carbohydrate mainly in the form of starch and 10-12% protein (Jha et al., 1991a, b). It is rich in minerals and is almost fatless (0.1%). Like other crops, several diseases attack makhana plants, but unlike elsewhere in field, these cannot be sprayed with chemicals, for they would kill the fish. There is no systematic study has been done for correct identification and diagnosis of different diseases of makhana and their management. Therefore, there is urgent need of correct
diagnosis and comprehensive understanding of the life cycles of the various diseases so that they can be managed at the most appropriate time, if they are causing economic loss. The most common diseases in Makhana are leaf blight, black and brown leaf spot, botrytis gray mold, root rot and development of tumors.
