Abstract

                                A survey was conducted on the occurrence of sugarbeet root rot caused by Sclerotium rolfsii in Tamil Nadu (India) during 2008-2009. Soil samples collected from conducive and suppressive soils were tested under pot culture conditions inoculated with sclerotia of S. rolfsii. Sugarbeet grown in disease conducive soils such as Ooty, Thondamuthur, Pollachi, and Bhavanisagar were observed with root rot incidence of 45.9, 54.2, 37.5 and 50 per cent respectively; whereas sugarbeet grown in the experimental plot of TNAU (suppressive soil) was free from disease. The physico-chemical properties of soils showed that the conducive soils were sandy loam to sandy clay loam, non calcareous with normal pH, while the suppressive soil were clay loam, calcareous with higher pH. Actinomycete population was dominant in the suppressive soil than conducive soils.

Key words : Actinomycetes, conducive soil, microbiological and physico-chemical properties, Sclerotium rolfsii, suppressive soil.