The present study was undertaken to explore the inhibitory effect of 
cyanobacterial extracts of Nostoc commune FA-103 against the tomato-wilt 
pathogen, Fusarium oxysporum f. sp. lycopersici. In an optimal medium, cell 
growth, antifungal activity, and antifungal compound production could be 
increased 2.7-fold, 4.1-fold, and 13.4-fold, respectively. A crude algal extract 
had a similar effect as mancozeb at the recommended dose, both in laboratory and 
pot tests. In vitro and in vivo fungal growth, spore sporulation and fungal 
infection of wilt pathogen in tomato seeds were significantly inhibited by 
cyanobacterial extracts. Nostoc commune FA-103 extracts have potential for the 
suppression of Fusarium oxysporum f. sp. lycopersici.