Fungicide Spraying during Ascospore Discharge by the Causal Fungus of Apple Blotch (Diplocarpon mali) Suppresses Development of the Disease

Abstract

The ascospore-discharge period of the apple blotch fungus and the effect of fungicide application during the discharge period on apple blotch development were investigated. Ascospore discharge started on 7 May 2001 and lasted until the beginning of July. When some effective fungicides were applied during the discharge period, the level of damage to apple trees by the disease was low. From these results, infection with ascospores is believed to be strongly associated with apple blotch development.