Bioassay of Volatiles Released from Mustard Leaf and Mustard Powder
Response of Sclerotium rolfsii, the causal agent of groundnut (Arachis hypogea L.), to toxic volatiles produced by the mustard leaf discs and different concentrations of mustard powder was studied. Mycelium plugs were exposed to inoculated leaf discs and powder of black mustard (Brassica nigra). Growth of S. rolfsii exposed to mustard leaf discs was inhibited more than 15.68% compared to controls. Despite inhibition of exposed fungal colonies, the fungus continued to grow in infected tissue. Repeated exposure of fungus to hydrated mustard powder (which contains both glucosinolates and myrosinase) resulted in growth inhibition up to 63.29% after 96 hours, suggesting that S. rolfsii has the ability to adapt to volatiles during the infection process.