The decrease of pathogenicity of pine wood nematode, Bursaphelenchus lignicolus, induced by the extended ubculturing on the fungal mat of Botrytis cinerea

Abstract

The extended subculture of B. lignicolus on the fungal mat of B. cinerea resulted in the decrease of pathogenicity to pine trees as well as the propagation rate. The population of B. lignicolus collected in 1969, which had been highly pathogenic inasmuch as they brought about the entire death of pine trees inoculated, exhibited the degradation of the pathogenicity after being subcultured on the fungi for 5 years. The population also showed a lower rate of propagation when compared with that of the injurious fresh population.