Inhibitory and compatibility effects of essential oils on sapstain and biological control fungi

Three essential oils (Ceylon citronella, Cedarleaf and Geranium) were evalu ated for their fungitoxic activity against four major sapstain fungi (Ophio stoma picea, Aureobasium pullulans, Alternaria alternata, Gliocladium virid e) and compatibility with one potential biocontrol fungus (Gliocladium rose um). Sapstain fungi, which belong to deuteromycetes and ascomycetes, genera lly colonize and discolor the sapwood of softwood and hardwood lumber. Gera nium and citronella oils inhibited growth of all fungi at medium (2.5%, vol ume/volume) and high (5%, volume/volume) concentrations respectively except for O. piceae and G. viride. Cedarleaf oil inhibited O. piceae at all conc entrations and A. alternata at only high concentration. Cedarleaf oil was a lso partially compatible with the biological control agent, G. roseum. None of the oils evaluated could he characterized as a selective sterilant.