Reduction of the post-harvest losses in organic beetroot production

Summary

The market for organic agriculture is rapidly growing. In Switzerland, the production of organic Beetroot is particularly renowned. However, their storage until spring has become increasingly difficult in recent years, and losses due to post-harvest rots can lead to over 50 % by March. Therefore, most organic beetroots sold in spring need to be imported. The causes for the various storage rots in beetroot are currently unclear, and therefore there are few measures to prevent them in organic production. Pathogen infections causing storage rots in beetroot, but also in other long-stored vegetables, can occur via the seed, in the field, or post-harvest. Understanding the process of infection is, therefore, critical to find preventive solutions. Here, we present the results of a two-year project aiming at reducing post-harvest losses in organic beetroot production. In a combination of on-farm field experiments and laboratory analyses, we aim to elucidate the causes of storage rots in organic beetroot and develop measures to improve storability. Analysis of stored beetroot in February 2021 revealed Fusarium species and Phoma betae as predominant pathogens in Switzerland. Botrytis cinerea, Rhizoctonia solani, and Pythium sp. were found as additional causative agents of storage rots. In summer 2021, a field trial in cooperation with four producers of organic beetroot was started, where the production from sowing to storage was monitored. Different measures, such as steam sterilization of the seed, the use of biocontrol products in the field and before storage, or processing and cooling methods after harvest, as well as cultivar differences were investigated. The various measures were found to affect seed health, seedling emergence, leaf health, and the quality of beetroot after storage.