VasudhaUdupa A - Department of PG Studies and Research in Applied Botany, Jnana Sahyadri, Kuvempu University, Shankaraghatta – ۵۷۷ ۴۵۱, Shimoga Dist. India
Balakrishna Gowda - Department of Forestry and Environmental Science, University of Agricultural Sciences, GKVK Campus, Bangalore- ۵۶۰۰۶۵ India
Shivanna M.B - Department of PG Studies and Research in Applied Botany, Jnana Sahyadri, Kuvempu University, Shankaraghatta – ۵۷۷ ۴۵۱, Shimoga Dist. India

Purpose Raw and composted oil-cakes of neem, madhuca and simarouba were evaluated for their effect on plant growth, yield, and management of Alternaria tenuissima leaf spot disease, and rhizosphere microorganisms in chilli crop.Method The oil-cakes were composted in simple pits containing a mixture (۶:۱:۱) of individual oil-cake, soil and rice straw. Growth promotion and disease incidence were assessed in plants grown in soil amended with raw or composted oil-cakes of neem, madhuca and simarouba in pot and field. Rhizosphere microflora was also determined in all treatments.Result Raw oil-cakes and their composts increased plant growth and yield and considerably decreased disease incidence and severity of A. tenuissima leaf spot in chilli grown in pot and field. The composted oil-cakes of simarouba were most effective in improving plant growth and yield and decreasing leaf spot disease in chilli, followed by madhuca and neem oil-cake compost. Fruit yield and vitamin C content were also high in simarouba compost. All composted oil-cakes increased beneficial microbial population in the rhizosphere, including phosphate solubilizers, free-living N۲ fixers and Trichoderma species. The compost amendment decreased A. tenuissima population in the soil at the same time.Conclusion The growth promotion, yield increase and disease reduction in chilli were attributed to chemical compounds in oil-cakes and stimulation of beneficial microbes in the rhizosphere by raw or composted oil-cakes. This study demonstrated that composted non-edible oil-cakes could be used for soil amendment in place of agrochemicals to increase productivity, manage soil-borne diseases and improve soil health.

Leaf spot, Oil-cakes, compost, Disease management, yield improvement