Antifungal activity of selected medicinal plants against Alternaria species: The pathogen of dirty panicle disease in rice

Antifungal activity of the ethanolic crude extracts from ten plants, namely: Curcuma xanthorhiza, Curcuma aromatica,  Kaempferia parviflora, Syzygium aromaticum, Origanum vulgare, Synedrella nodiflora, Sorghum bicolor, Rosmarinus officinalis, Piper longum and Eupatorium odoratum were tested against Alternaria species (the pathogen of dirty panicle disease in rice) by poisoned food technique at 0, 1,000, 2,500, 5,000, 7,500 and 10,000 ppm. The inhibition of mycelial growth and spore germination were evaluated. The results showed C. aromatica, S. aromaticum and O. vulgare crude extracts at 1,000  ppm, the R. officinalis crude extracts at 5,000 ppm, and the C. xanthorrhiza crude extracts at 10,000 ppm showed the highest inhibition of mycelial growth at 100%, whereas S. nodiflora and S. bicolor crude extracts at 10,000 ppm had the inhibition at 56 and 58%, respectively. For inhibition of spore germination, the three plant crude extracts; C. aromatica, S. aromaticum and O. vulgare at 1,000 ppm and C. xanthorrhiza, S. nodiflora, S. bicolor, R. officinalis and P. longum crude extracts at 2,500 ppm reached the highest inhibition of spore germination at 100%, whereas E. odoratum and K. parviflora crude extracts at 10,000 ppm had the inhibition at 20 and 55%, respectively. Key words: Antifungal activity, dirty panicle disease, Alternaria species, medicinal crude extract, rice.