Kansas Aeromycology XIII: Diurnal Studies 1959–60

SUMMARY

Using silicone slides and nutrient plates to study diurnal periodicity in airborne fungi in Kansas between October, 1959, and November, 1960, 16 24-hr and one 48-hr series were made. Viability studies were made of the spores. Most of the series were at 2-week intervals during the growing season, but some were during the fall and winter.

Great variation was found from series to series and also from hr to hr. The highest spore number was 2718/ft³, July 13, 1960, and the highest number of colonies 1100/ft³, October 14, 1960. Commonest spores were 1-celled hyaline, which occurred at night and after rains. The maximum was 1800/ft³ at 2 AM, June 10, 1960. Basidiospores were next in abundance with a peak of 566/ft³, October 20, 1960. Cladosporium was present in all series with highest numbers in late summer and fall, with a peak of 376/ft³, October 28, 1960. Yeast colonies were generally present, but were low in number except October 14, 1960, when they reached 1000/ft³. Sterile colonies were common and frequently abundant with a peak of 240/ft³, June 9, 1960.

Fusarium, Alternaria, Penicillium, Aspergillus, and hyphal fragments usually were present but numbers were usually below 50/ft³. Of less frequent occurrence in the plates were smut-like colonies, Phoma, Sporotrichum, Pullularia, Cephalosporium, Fusidium, Coniothyrium, Epicoccum, Geotrichum, Chloridium, Curvularia, Beauveria, Scopulariopsis, Stemphylium, Helminthosporium, Rhizopus, and Sirodesmium, and 47 additional genera only occasionally found.

Diurnal periodicity was displayed only by the 1-celled hyaline spores and basidiospores, which had definite nighttime peaks. When yeasts were abundant, their peaks were at night. Cladosporium and Alternaria were very irregular, commonly without any marked peaks, but in some series there were morning, afternoon, and evening peaks, and not infrequently 2 or more minor peaks.

Although numbers in winter were generally low, conditions frequently favored spore production, as December 31, 1959, when 335/ft³ were found with basidiospores reaching 286/ft³ and displaying typical diurnal periodicity.

In most series, spore viability ranged from 30–60% but occasionally reached as high as 90%.