Seaweed Extracts Control the Leaf Spot Disease of the Medicinal Plant Gymnema Sylvestre

Antimicrobial screening of 12 different seaweeds extracts namely Chaetomorpha antennina, Dictyota dichotoma, Enteromorpha flexuosa, Laurencia obtusa, Gracilaria corticata, Gracilaria verrucosa, Grateloupia lithophila, Padina boergesenii, Sargassum wightii, Turbinaria conoides, Halimeda tuna and Ulva lactuca was carried out in vitro . The crude extracts were tested against the phytopathogenic bacterium- Pseudomonas syringae causing leaf spot disease of the medicinal plant Gymnema sylvestre . The methanolic extracts of Sargassum wightii showed maximum activity followed by ethyl acetate compared to that of other organic solvent- extracts. Thus, this investigation throws fresh light on the appropriate usage of solvent extraction method in preparing potent biopesticide.