Didymella ascospores in derby

Abstract The main Didymella ascospore season in Derby is June-September. 10 day running means for the years 1986–1988 have been compared with 10 day running means of rainfall and maximum temperatures. The high temperatures reached in 1987 together with substantial rainfall were very favourable for Didymella ascospore release. Diurnal periodicity showed that the expected night time pattern was only occasionally disturbed by day time rainfall. Didymella ascospore liberation is greatly increased when both temperature and rainfall are high. Temperatures of about 20° in the period before rainfall appear to greatly increase the numbers of Didymella ascospores liberated. Air has been sampled for fungal spores in Derby for many years and there is evidence of an upward trend in the June-September seasonal mean concentrations of Didymella ascospores since 1985 with no corresponding trend apparent in the corresponding June-September rainfall totals. Seasonal mean concentrations for 1985, 1987, 1988 and 1992 were at ...