Toxicity of Essential Oil from a New Strain of Ocimum gratissimum (Clocimum) against Betelvine Pathogenic Fungi

The leaves of Ocimum gratissimum (Clocimum) exhibited strong volatile fungitoxicity against betelvine (Piper betle L.) pathogens—Alternaria alternata, Colletotrichum capsici and Sclerotium rolfsii. Fifteen compounds could be identified from the fungitoxic constituents—the essential oil. The oil at its minimum inhibitory concentrations of 50, 250 and 500 ppm against S. rolfsii, A. alternata and C. capsici, respectively, was fungistatic, although, fungicidal at higher concentrations. Eugenol was found to be the major fungitoxic principle in the oil. The oil was either equally effective or superior to synthetic commercial fungicides and was non-phytotoxic to the host plants. Thus, the oil can be used as a valuable indigenous and biodegradable agent against fungi that cause losses to the betelvine industry.