Identity and occurrence of Venturiaceous spores in the air at Cambridge

Abstract

Airborne ascospores and conidia which were thought to resemble the spores of Venturiaceous fungi and ascospores and conidia of reference material are described and illustrated. A comparison of airborne spores and reference material allowed the identification of most of the airborne spores. The importance of considering only fully mature ascospores in reference material is emphasised. Dark transverse bands in the ascospores of Venturia macularis and the upper cells of immature ascospores of V. pyrina are described for the first time, and ascospore dimorphism is noted in V. ditricha. Ascospores of V. ditricha, a parasite of Betula species, ascospores resembling those of V. crataegi, and ascospores of the unidentified ‘Visual type D’ are common in Cambridge air spora, but ascospores of other species, and conidia of all the species are much rarer. The seasons during which spores were present in the air is reported and discussed briefly.