The Summer Air-Spora at Rothamsted in 1952

Abstract

The air over an arable field at Rothamsted Experimental Station was sampled from June to October, 1952 at 2 m above ground with an automatic volumetric spore trap. Each day''s slide was scanned and all the spores counted on an area representing a sample volume of 411 of air. Spores were classified in 20 morphological groups and a miscellaneous one. Seasonal periodicities are presented as 6-day running means of the daily average number of spores/m3 air, and then related to meteorological data. Cladosporium conidia accounted for 45% of the total catch; hyaline basidiospores (chiefly Sporobolomyces) for 31%; and pollen only 1%. The relative frequency of various spore types differs from that recorded by earlier workers because the suction trap catches spores of all sizes with almost equal efficiency and is little influenced by external conditions. The results which should be representative of large rural areas of central and south England show that the major changes of spore concentration depend on the weather and the phenology of the local vegetation and its associated fungal flora.