- D H Swarts and T Anderson
- Citrus and Subtropical Fruit Research Institute, Nelspruit
- 1988
Chemical control of postharvest mould growth on litchis was investigated. The best results were obtained by dipping the fruit for 10 minutes in a suspension of 0,375 g dicloran 50 per cent wp plus 0,625 g benomyl 50 per cent wp per litre water, which was preheated to a temperature of 52°C. Dipping of the fruit in cold (± 25°C) fungicide suspensions, was much less effective.
Summary:
- The study investigated chemical control methods to reduce postharvest mould growth on litchis during storage and sea shipment.
- The best control was achieved by dipping litchis for 10 minutes in a hot (52°C) suspension of 0.375 g dicloran 50% WP plus 0.625 g benomyl 50% WP per liter of water.
- Cold fungicide dips at 25°C were much less effective than hot treatments.
- Litchis are highly susceptible to a wide range of moulds during storage and shipment, including Colletotrichum, Pestalotia, Botryodiplodia, Cylindrocarpon, Aspergillus, Rhizopus, and Penicillium species.
- More than 40 fungicides were initially screened; many were phytotoxic, affected flavor, or left undesirable residues.
- Hot water (52°C) dips alone offered some control but re-infection occurred without fungicides.
- Mixtures of fungicides were more effective than single chemicals.
- The dicloran and benomyl mixture reduced postharvest decay to less than 10%, with acceptable residue levels when the ratio was 0.375 g dicloran to 0.625 g benomyl.
- Litchis require continuous refrigeration after cold storage to prevent rapid deterioration; shelf life after cold storage is only about three days at room temperature.
- The treatment used in the study is not yet registered for commercial use on litchis.
- Proper chemical treatment combined with refrigerated storage is necessary for successful sea shipment of litchis without decay.