Automatic Volumetric Spore Trap Research Articles

The air spora of a cowshed.

SUMMARY: Study of the air spora of a cowshed by means of a Hirst Automatic Volumetric Spore Trap showed an atmospheric concentration of fungal spores ranging from 95,000 to 16,000,000 spores/m3. There was a direct relationship between the hours during which hay was being fed and the highest concentrations of spores. Asper-gillus-Penicillium and Mucor types of spore were predominant, and hyphal fragments including conidiophores were the third most numerous component. The findings are discussed with reference to human and animal fungal disease.

The diurnal and seasonal periodicity of spores of certain plant pathogens in the air

Using an automatic volumetric spore trap for sampling air at 2 m. above ground in an open field at Rothamsted Experimental Station, Harpenden, the diurnal and seasonal periodicities of 15 spore types belonging to fungi pathogenic to plants were followed during June to September, 1953. Large numbers of smut spores and conidia of powdery mildews occurred very early in the season when spores of Botrytis and Periconia also reached their peak. Uredospores of rusts and Helminthosporium spores were in maximum numbers during the middle of the season and spores of Polythrincium and Epicoccum occurred in large numbers towards the end of the season. Alternaria and Stemphylium spores began to appear during the middle of the season and persisted till the end. Spores of Tilletia , probably liberated into the air during the threshing operations, were seen in appreciable numbers towards the end of the season. Spores of Ganoderma were present over the whole period, while those of Coniophora occurred over a very short time. It was found that in dry weather many showed typical diurnal periodicity. Ustilago, Helminthosporium , uredospores, Botrytis, Alternaria, Stemphylium and Periconia were most abundant in the afternoon and least in the early morning. Erysiphe, Polythrincium and Epicoccum also occurred during the daytime but reached their maxima before noon. Spores of Ganoderma, Coniophora and other coloured basidiospores were found to occur in great concentrations between midnight and dawn. The changes observed during this crop season were compared with the existing data and it was concluded that the changes described were, in general, representative of large rural inland agricultural areas in temperate regions.

Volumetric counts of pollen grains at Cardiff, 1954–1957

1. 1. The article presents the principal results of a four-year pollen census carried out with a Hirst automatic volumetric spore trap. 2. 2. Direct volumetric estimates have been made of the pollen incidence of the various types of pollen concerned; the potential value of such estimates in the study of inhalant allergy needs no emphasis. 3. 3. The survey has confirmed the general conclusions (based on a much longer gravity slide census) on the qualitative and (with the exceptions stated below) the quantitative botanical composition of the pollen cloud over South Wales, on the phenology and (with the same exceptions) the relative abundance of its constituent types, and on their variation from year to year. 4. 4. Use of an efficient volumetric trap has made possible a more correct assessment of the numerical abundance of certain types (notably Urtica) whose relative importance, by reason of their small size, had previously been underestimated. 5. 5. Attention is drawn to especially wide variations in the annual incidence of certain principal types and to the need to consider such variations when the effects of treatment are assessed.

Spore dispersal in Ophiobolus graminis and other fungi of cereal foot rots

During Oct. 1953, air was sampled with a Hirst automatic volumetric spore trap at a height of 0·5 m. above the stubble of a wheat crop bearing fructifications of Ophiobolus graminis, Cercosporella herpotrichoides and Fusarium culmorum. Ascospores of O. graminis were never caught on rainless days; nor after rain of less than 0·01 in. They were caught within an hour of 0·01 in. or more rain and attained a maximum concentration of 3700 per m.3 of air within 2 hr. of 0·05 in. rain. Wind-tunnel tests showed that the peak rate of liberation occurred within 45 min. of wetting. All mature ascospores seemed to be discharged during 4 hr. of rain, but a few dry days sufficed for another batch to mature. C. herpotrichoides behaved differently : a few conidia occurred after a trace of rain, and more rain did not increase their numbers; their maximum concentration was only one-tenth of O. graminis. Concentrations of coloured basidiospores were more nearly constant, regardless of weather and time of day, and Cladosporium was more common by day than by night. No macroconidia of Fusarium were detected.

The summer air-spora at Rothamsted in 1952.

SUMMARY: The air over an arable field at Rothamsted Experimental Station, Harpenden, was sampled from 1 June to 25 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 41l. 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/m.3 air, and then related to meteorological data. Cladosporium conidia accounted for 46 % 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. During 24 days in late June and July comparable estimates of spore concentration were made with another trap 24 m. above ground. The spore concentration of the twelve commonest groups at 24 m. totalled 82 % of that at 2 m.