Effect of meteorological parameters on growth and sporulation of alternaria alternata causing alternaria fruit rot of brinjal

摘要

Brinjal (Solarium melongena L.) is a major solanaceous vegetable crop of India. It contributes about 12.47 per cent of the total production of vegetables in India. In Rajasthan, it is grown in all districts in an area of5738 hectares with 37253 metrictonnes production and productivity of 6.49 metric tonnes per hectare (Anonymous, 2007-08). A heavy infection of Alternaria fruit rot of brinjal caused by A. alternata (Fr.) Keissler was observed in the vicinity of Jobner (Jaipur). In India, the diseaseAlternaria fruit rot of brinjal was first reported from IARI, New Delhi. This disease is severe and appears regularly, causing heavy losses in fruit yield. The disease appear in two phases, leaf spot and fruit rot. The disease first makes its appearancein young seedling during the rainy season (July-August) which is blighted. They give a cherry appearance and finally die out. In September, it attacks on leaves and then spread to fruits which rot and become unfit for consumption. Lesions of fruits arefirst observed during February. They start as small (above 1/ 2cm in size), concentric, dark brown and sunken spots. Colour of the lesions become olivaceous dark brown due to spore formation. Several lesions may coalesce and cover the entire surface of the fruit (Kapoor and Hingorani, 1958). Fungus produces muriform conidia and usually formed in chains (Fig. 1 & 2). To find out the role of environmental factors such as temperature, relative humidity and light/darkness on the disease development, in vitro studies were conducted at Department of Plant Pathology, SKN, College of agriculture, Jobner during 2009-10.