Influence of non-edible oil-cakes and their composts on growth, yield and Alternaria leaf spot disease in chilli

Authors

• VasudhaUdupa A ¹
• Balakrishna Gowda ²
• Shivanna M.B * ¹

1. Department of PG Studies and Research in Applied Botany, Jnana Sahyadri, Kuvempu University, Shankaraghatta – 577 451, Shimoga Dist. India
2. Department of Forestry and Environmental Science, University of Agricultural Sciences, GKVK Campus, Bangalore- 560065 India

Abstract

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 (6:1:1) 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 N₂ 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.

Highlights

• Alternaria tenuissima cause leaf spot disease in chilli crop and is the cause of reduced yield.
• The first study on the use of oil-cakes of neem, madhuca and simarouba in controlling leaf spot in chilli;
• The oil-cake application inducing systemic resistance in chilli plants;
• Providing baseline information on the application of composted oil-cakes for yield improvement and disease management in chilli crop

Keywords

• Disease management
• Leaf spot
• Oil-cakes
• Yield improvement
• Compost