Emulsive water (EW) formulations prepared from non-polar fraction of sorghum root exudates were most inhibitory to seven test pathogens. It was most lethal to Sclerotinia sclerotiorum and Sclerotium rolfsii at LD50 values of 17 and 22 μg g−1, respectively. Against Fusarium udum and Fusarium oxysporum sp. ciceri Emulsifiable concentrate showed relatively higher LD50 values of 250 and 270 μg g−1 respectively. Against Rhizoctonia bataticola, Alternaria alternata and Choenephora cucurbitarum LD50 values of developed EC were 182, 146 and 87.5 μg g−1, respectively. Detrimental effect of EC was also observed on number and size of sclerotia and their viability against two most sensitive fungi viz., Sclerotinia sclerotiorum and Sclerotium rolfsii. At different concentrations, it inhibited the sclortia viability, where depended on EC concentration in medium. Reduction in number and size of sclerotia of both pathogens was observed at increased concentration. Similarly, increase in concentration reduced the viability of sclerotia from 93.7% in untreated to 43.7% at 250 μg g−1. All collected root exudate was separated into five different fractions viz., A, B, C, D and E by fractional crystallization. Each fraction was predominantly (>90%) rich in single allelopathic compound (HPLC). 1HNMR analysis of extra-purified fractions revealed the presence of identical aromatic chemical moiety in all fractions. EPR analysis of fraction D confirmed the presence of three anti fungal paramagnetic elements viz., Mn++, Cu++ and Fe+++ ions, where the inorganic element remained compounded with organic molecules.
Allelopathy, Allelocchemicals, Alternaria alternata, Fusarium oxysporum sp. ciceri, Fusarium udum, Rhizoctonia bataticola, Sclerotium rolfsii, Sclerotinia sclerotiorum, root exudates, sorghum, Sorghum vulgare
