Injury to currants during mechanical harvesting and subsequent fungal infection

Authors

• Risto Tahvonen Department of Plant Pathology, University of Helsinki, 00710 Helsinki 71, Finland

DOI: https://doi.org/10.23986/afsci.72007

Abstract

Mechanical harvesting did not cause significant damage to blackcurrants. Redcurrants suffered extensive injuries, which gave rise to dieback. In addition to mechanical injuries, the pathogen Botrytis cinerea Pers. aggravated bieback of the branches, and severely inhibited healing of the wounds. In wounds on both red- and blackcurrants, the commonest fungus was Alternaria tenuis auct. This fungus did not inhibit healing of the wounds, indeed it appeared to reduce the incidence of B. cinerea wound infection. The wounds contained 19 other fungal species and genera of no pathogenic importance. In a colder-than-average autumn, B. cinerea infection was more severe, and dieback during the subsequent season more extensive than usual. A methyl thiophanate application made in a cold autumn after harvesting reduced the incidence of B. cinerea in wounds, and little dieback resulted the following year. In mild autumns maneb and dichlofluanid reduced dieback, too. When the harvesting was followed by a cold autumn, mechanical harvesting reduced the following year’s yield compared with hand-picking.