Early diagnosis of Ganoderma infection in indicator plants through ELISA and visual observation

摘要

Basal Stem Rot (BSR) disease in coconut incited by the fungus Ganoderma lucidum (Leys) Karst (Bhaskaran and Ramanathan, 1983) is one of the main limiting factors in coconut cultivation. It is a severe disease in India and in some cases the incidence as high as 31% was recorded (Anonymous, 1987). The disease is responsible for significant reduction in yield of nuts every year in India and in some Asian countries (Bhaskaran et al, 1984). Management practices are effective only when the disease is diagnosed at the early stages. Trees can be saved from the disease if reliable diagnostic methods are available. A few methods have been reported to be useful for early diagnosis of the disease (Vijayaraghavan et al. 1987). A colorimetric method using ethylene diamine tetra acetic acid (EDTA) was reported by Natarajan et al. (1986) in which optical density of the sap from infected stem tissues was found to increase with increase in disease intensity. Use of indicator plants for the early detection of basal stem rot in coconut was also reported (Srinivasulu et al., 2006). In the present study attempts were made to test the use of DAC-ELISA in early detection of BSR disease and also by using indicator plants.