Observations on the Periodicity in the Air-Borne Spores of Ganoderma Applanatum

SUMMARY

The periodicity in the air-borne spores of Ganoderma applanatum (Pers. ex Fr.) Pat. was studied by sampling air continuously, with a Hirst spore trap, near three large mature actively sporulating perennial fruit bodies growing on the trunk of a living tree in the Imperial College Field Station, Ascot, U.K., from 27 June to 30 July, 1955 and 13 June to 16 August, 1956. In both years daily mean concentrations of more than 2,000/m³ of air were encountered on many days. A regular and sharply defined “nocturnal pattern” of diurnal periodicity (with the daily maximum recurring at about midnight and with very low concentrations during the daytime) was observed on normal dry days. From the hourly changes in the concentrations during three periods, it was shown how changes in the weather conditions (especially rainfall at night) alter the diurnal periodicity pattern. The existence of humid conditions associated with low temperatures and high relative humidity (in cloudy weather even without rain) was also found to influence the diurnal rhythm. The highest concentration measured exceeded 21,000/m³ of air.