Storage fungi of onion and their control

Authors

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

DOI: https://doi.org/10.23986/afsci.72053

Abstract

Botrytis allii Munn caused total onion damages of 15—20 % during storage in 1975—1979, and was present on 80—90 % of the spoilt onions. The proportion of damage caused by Fusarium oxysporum Schl. was 0—5 % and was present in 0—10 % of the spoilt onions. The early weight losses during storage of the onions were mostly due to storage pathogens which spread via the onion sets used as propagation material. This can be prevented very effectively by soaking the sets in benomyl solution before planting out. The unusually high fungus content of the sets resulted in a reduced yield. Spraying with fungicide early on in the growing season and applying different amounts of nitrogen fertilizer had no significant effect on the number of storage pathogens. A low stroge temperature did not inhibit the development of storage pathogens, it merely slowed it down.