Brinjal, eggplant or aubergine (Solanum melongena L.) is a major vegetable crop of India after potato. It is grown in all seasons and almost in all the parts of India except on higher altitudes. Leaf spot of disease were appears in two phases leaf spot and fruit rot caused by Alternaria alternata (Fr.) Keissler. It is mainly an outdoor whose spores disseminate in warm, dry air, so in temperate climate, their count peacks in the summers. Pathogen on crop plants reason huge yield losses, reduce the economic value of the crop plants in conventional production system and are very difficult to manage. Survey conducted in Brinjal fields in the different climatic condition was recorded the disease intensity of leaf spot (A. alternata). The maximum leaf spot disease intensity 39.01% was recorded in old plants, whereas, it was minimum disease intensity recorded in 9.20% in newly plant in areas surveyed. Fruit rot disease incidences was recorded more than 50%. In leaf spot symptoms is as small, circular, brown, necrotic spots with a chlorotic halo. They gradually emerged and coalesced are causing withering and shedding of the leaves. There are concentric rings with a deep greenish blue growth of the fungus. Lower leaves are first attacked than upper leaves and fruit. The fungus is isolated from infected leaves and found to be pathogenic as seed and spore cum myceial suspension under artificial inoculation condition. Microscopic observations of the isolated fungus revealed that the mycelium is septate, with dark brown hyphae and conidia, when observed singly and irregularly branched, measuring 2.7-4.4 µm in width. The conidiophores are dark brown in color, septate, branched and measured 34.0-93.0 µm in length and 3.4-9.0 µm in width. The conidia are dic-tyospores and transversely septate. The environmental factors during the crop season play and important role in disease development because temperature and relative humidity are two important external factors, which is influence the growth of pathogen as well as it pathogenesis. Maximum disease occurred when temperature are ranged from a maximum of 28.7-32.2 o C to a minimum of 15.5-20.3 o C and relative humidity from 62.74 % to 32.46%. Management of leaf spot and fruit rot are fungicides like Indofil Z-78, Vitavax, Benlate, Thiram, Karathane, Calaxin, Rid-omil, Miltox, Plantvax, Captan, Brestan-60, Dithane M-45, Difolatan, Cuman L, carbendazim+mancozeb, copper oxychloride, iprodione, thiophanate methyl , Zineb, propecanazole and hexacanazole gave satisfactory management, but are dangerous to the ecosystem. Other methods are managing alternaria