A Study on the Effect of Different Soil pH on Sclerotinia sclerotiorum Infection and Growth of Mentha arvensis

Abstract

Sclerotinia sclerotiorum is a broad-host-range phytopathogenic fungus. It also effect plants of Mentha arvensis, source of menthol which has great demand in pharmaceutical, flavouring and cosmetic industries. The present study was carried out to determine the role of soil pH (4.5, 6.0, 7.5 and 9.0) on S. sclerotiorum infection and the growth, biochemical parameters and oil yield of M. arvensis and in pot condition. Results showed that soil pH had effected either positively or negatively the growth and oil yield of M. arvensis. The maximum percent reduction in shoot height (20.1 %), shoot dry weight (25.8 %), roots and suckers dry weight (27.2 %) and oil yield (9.37 %) was observed in plants grown in soil pH 4.5 and inoculated with S. sclerotiorum. The maximum roots/suckers S. sclerotiorum infection was 52 % at pH 4.5. Chlorophyll a, chlorophyll b, total chlorophyll, total phenol and total sugar content of the plants inoculated with S.sclerotiorum as well as uninoculated plants increased with the increase in soil pH. Results demonstrated that pH is an important factor influencing the disease development and also affecting plant growth, oil yield and biochemical parameters.