Pg. 10-14 Post-harvest control of decay and browning of litchi fruit by fungicide dips and paper sheets impregnated with sodium metabisulphite

Integrated control is necessary to increase the shelf-life of litchis. This can be done by a dip treatment of Benomyl (600 ppm), Prochloraz (250 ppm) and a fruit coating compound, Semperfresh F (1%) to prevent decay, followed by the incorporation of two slow releasing sodium metabisulphite (SMS) paper sheets on both sides of the litchis in polyethylene bags to prevent browning. The cv Madras requires a much higher SO₂ concentration than the cv Mauritius. A storage temperature of 3,5°C is recommended for both cultivars.

Summary:

• Integrated control is necessary to extend the shelf-life of litchi fruit.
• Effective post-harvest treatment includes fungicide dips using Benomyl (600 ppm) and Prochloraz (250 ppm) combined with a fruit coating compound, Semperfresh F (1%) to prevent decay.
• Browning prevention is achieved by placing slow-releasing sodium metabisulphite (SMS) paper sheets on both sides of the fruit inside polyethylene bags.
• The Madras cultivar requires a higher sulfur dioxide (SO₂) concentration than the Mauritius cultivar for browning control.
• Recommended storage temperature for both cultivars is 3.5°C.
• Litchis are highly susceptible to post-harvest decay and browning, especially under low humidity conditions.
• Polyethylene packaging enhances freshness by maintaining higher humidity and reducing browning and weight loss.
• Fungicide treatments that wet the fruit surface may promote decay; proper dipping agents like Benomyl and Prochloraz are effective in controlling decay.
• Slow and fast-releasing SMS sheets have been evaluated; slow-releasing sheets are more effective in reducing browning and decay.
• Combination treatments of Semperfresh, Benomyl, and Prochloraz provide excellent decay control, though browning may vary by temperature.
• The use of SMS sheets with polyethylene bags significantly reduces browning and extends marketable fruit life.
• High concentrations of sodium metabisulphite in SMS sheets should be carefully managed to avoid sulphur-burn.
• Overall recommendations include maintaining cold storage at 3.5°C, using fungicide dips, fruit coatings, polyethylene packaging, and appropriate SMS sheets for optimal post-harvest decay and browning control.