Die Marillenblattbräune (Gnomonia erythrostoma) : Biologie und Versuchsergebnisse

Apricot leaf scorch caused by Gnomonia erythrostoma - Biology and trial results. The first epidemic appearance of Gnomonia erythrostoma in Austrian apricot orchards was reported in the mid 80ies in the Lower Austrian region Wachau. Since then Gnomonia erythrostoma has been appearing regularly with varying severity. In field trials and laboratory tests the connection between precipitation and ascospore discharge has been shown. We also found that the release of ascospores does not depend on the luminous intensity, ascospores of Gnomonia erythrostoma are discharged in the dark, too. Trials showed that fungicides of different active substances applied during the primary infection period give sufficient control. Best results were obtained with specific sprays shortly after rainfall. Trials to reduce the ascospore inoculum by spraying the leaves in autumn with nitrogen containing fertilizers showed a reduction of the ascospore inoculum in spring of up to 90 %.