| Abstract: | Seven 6-alkyl-3-n-butyl-7-hydroxy-4-methylcoumarins and three other related substituted coumarins were synthesised, characterised and tested for their toxicity towards mycelial growth of seven phytopathogenic fungi in culture. Rhizoctonia solani, Alternaria alternate, and Drechslera oryzae exhibited maximum sensitivity to these compounds whereas Pythium aphanidermatum, Colletotrichum falcatum, Fusarium solani and Macro-phomina phaseolina were less sensitive. The 6-n-butyl and 6-n-pentyl derivatives possessed strongest toxicity towards all fungi except C. falcatum but the corresponding 6-n-propyl derivative was inhibitory to only D. oryzae and A. alternata. |
