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One of the key impediments for the cultivation of cucurbit vegetables is the pathogenic infestation. Besides, some abiotic causes are also involved in lowering crop yields in terms of both quality and quantity. Cucurbits are suffering from different kinds of pre- and post-harvest biotic stresses like fungi, bacteria, virus, phytoplasma, nematodes, etc. The abiotic factors are related to excess or deficient supply of nutrients, adverse edaphological and climatological conditions, etc. Some of the economically important and destructive diseases are downy mildew, powdery mildew, damping-off, fruit and vine rot, cottony leak, gummosis, Phytophthora blight, anthracnose, Cercospora leaf spot, phoma blight, collar rot, charcoal rot, Fusarium wilt, white rot, root knot, bacterial wilt, watermelon bud necrosis and leaf distortion virus, mosaic, phyllody, etc. Most of the diseases are of national importance and cause significant losses of the crops. A comprehensive catalogue on biotic diseases of cucurbits and their eco-friendly management strategies are presented in this chapter.

The field experiments were conducted during Rabi season of 2014-15 and 2015-2016 in Birbhum district under Lateritic Red and Undulating Agro-climatic region of West Bengal to find out the field efficacy of different fungicides against late blight of potato (cv. Kufri Jyoti). During 2014-15, among seven fungicides, Chlorothalonil 75% WP at 2 g/litre of water was recorded more efficacious. In 2015-16, three fungicides were evaluated in different doses to standardize the effective dose of Ethaboxam 40% SC and its bioefficacy in field condition against late blight of potato. Foliage and tuber infection were significantly lower and tuber yield recorded higher in Ethaboxam treatments when applied at 1.33 ml/litre of water. There were no significant differences between two different doses (1 ml and 1.33 ml/ litre of water) of Ethaboxam. Among eleven fungicides tested, Ethaboxam were also recorded superior in case of seed-tuber treatment-cum-spraying experiment.

Aim: To develop method for rapid and simple laboratory evaluation of fungicides against Phytophthora infestans, the causal pathogen of late blight of potato. Study Design: Descriptive statistics and analysis of variance. Each treatment was replicated thrice. Place and Duration of Study: Department of Plant Protection, Palli-Siksha Bhavana (Institute of Agriculture), Visva-Bharati, India in February, 2014. Methodology: Small portion of potato leaf tissue from advancing margin of late bight lesion is placed on water since Phytophthora infestans (Mont.) de Bary grow well in water producing hypha and sporangium. Using this property, performance of fungicides on mycelial growth and sporangia production/formation was assayed by placing a small bit of infected leaf tissue in different Short Research Article Mondal et al.; JSRR, 4(2): 168-173, 2015; Article no. JSRR.2015.019 169 concentration of fungicides. Results: Among the seventeen fungicides tested, chlorothalonil, fenamidone + mancozeb and tricyclazole inhibited mycelial growth and sporangia production but dimethomorph, tebuconazole + trifloxystrobin inhibited sporangia production only. Metalaxyl + mancozeb totally inhibited mycelial growth at higher concentration. Conclusion: This method can be useful for evaluating and comparing performance of different fungicides and even same formulations of a fungicide, produced by different companies within a very short time period. The experimental work can be completed within 48 –72h if late blight infected leaves are available.