Abstract
Leaf extracts of four plant species, Piper betle, Ocimum sanctum, Nyctanthes arbor-tristis and Citrus limon were effective in reducing the radial in vitro growth of Pyricularia oryzae, Cochliobolus miyabeanus and Rhizoctonia solani. P. betle was found to be the best, followed by O. sanctum, in reducing the growth of the pathogens completely in vitro and in checking the spread of blast, brown spot and sheath blight diseases of rice in vivo. Though the leaf extracts from the other two plant species tested (N. arbor-tristis and C. limon) reduced the radial growth of the pathogens in vitro at a higher concentration, they failed to check their spread effectively in the glasshouse. P. betle and O. sanctum could be used as source of a pesticide of plant origin to combat the above three pathogens of rice in the field.
