Abstract: The effects of diterpenic acids from pine needles of P.massoniana on the mycelial growth of Botrytis cinear, Sclerotinia sclerotiorum and Fusarium graminearum were studied by the mycelial growth rate method. The pot method was used to investigate its control effects on Sphaerotheca fuliginea. Results showed that diterpenic acids from pine needles of P.massoniana have significant inhibitory activity against the mycelial growth of B.cinerea, S.sclerotiorum and F.graminearum and their EC₅₀ values are 97.79, 14.94 and 76.39mg/L respectively. The control fuction against S.fuliginea was obvious, when the EC₅₀ value is 84.07mg/L. The toxicity against 4 kinds of plant pathogenic fungi was strengthened with the increased concentration of diterpenic acids from pine needls of P.massoniana.

Key words: pine needles, diterpenic acids, plant pathogens, antifungal activity