FUNGICIDAL ACTIVITY OF RANUNCULUS-ASIATICUS AND OTHER WEEDS AGAINST FUSARIUM-OXYSPORUM F SP LYCOPERSICI

The effects of aqueous extracts of some common weed species against Fu sarium oxysporum Schlecht f.sp. lycopersici (the causal agent of tomat o wilt disease) were investigated under laboratory conditions. Anagall is foemina L., Cerastium dicotomum L., Falcaria vulgaris L., Ranunculu s asiaticus L., Scorpiurus muricatus L. and Solanum nigrum L. extracts were the most toxic to the fungus. Further studies on buttercup (Ranu nculus asiaticus L.) showed that fresh shoot extract of this species p revented growth of F. oxysporum when incorporated into agar medium. Ex tracts of different parts of the plant inhibited fungus growth and spo rulation, but the fungitoxicity decreased with incubation period with only slight changes in the toxicity of fresh shoot extract. The shoot and fresh parts extracts were more toxic than root and dried tissue ex tracts. Addition of 0.5 ml fresh shoot or 1 ml fresh root extract to t he growing medium significantly reduced fungal colony growth, and the effect was extract concentration dependent. Fresh shoot extract of R. asiaticus added to a liquid medium significantly reduced mycelial dry weight compared with the control, and incorporation of 0.1 g dried sho ot or 0.2 g dried roots in the media strongly inhibited fungus growth. Results of a pot experiment showed no harmful effects of R. asiaticus extracts on tomato growth.