THE OCCURRENCE OF AIRBORNE DIDYMELLA SPORES IN EDINBURGH

Concentrations of Didymella ascospores, a cause of late summer asthma, reached peaks of 4400 m(-3) in urban Edinburgh. There were three main periods of peak concentration in most years, late-July, mid-August an d mid-September, which might be related to periods of spore maturation on ripening cereal crops. Peak counts occurred at night, were not dep endent on rain, but were associated with high humidity. No correlation s between spore counts and meteorological factors were found which cou ld be useful in predicting high spore counts.