PRINCIPAL INVESTIGATOR: Prof. Lise Korsten
CONTACT DETAILS: +27 12 420 3295 / +27 79 522 8476 / lise.korsten@up.ac.za
DURATION: Three years
PHI-1 CONTRIBUTION: R234 000
LEAD INSTITUTION: University of Pretoria (Department of Microbiology and Plant Pathology)
BENEFICIARY: The subtropical fruit sector
Amidst pressure to compete effectively with emerging mango export countries like Peru, Brazil and Chile, the South African subtropical fruit sector experienced a declining trend in export volumes. A contributing factor to this downward trend was an increase in soft brown rot and anthracnose post-harvest diseases. Treating export fruit in pack houses with a hot water and cold prochloraz dip generally controls these diseases. However, there is an international demand to reduce the use of synthetic pesticides. This study focused on the development of alternative environmentally friendly disease control strategies.
Evaluating the effect of cold storage treatments and biological control
Prof. Lise Korsten and Prof. Dharini Sivakumar supervised a project at the Department of Microbiology and Plant Pathology of the University of Pretoria. The study was focused on improving the quality and shelf life of South African mangoes.
- Tests were conducted on the ‘Kent’ and ‘Tommy Atkins’ cultivars.
- Some of the fruit was inoculated with the post-harvest pathogens responsible for soft brown rot (Botryosphaeria parva) and anthracnose (Colletotrichum gloeosporioides).
- The efficiency of environmentally friendly alternatives was evaluated by dipping some of the inoculated fruit into a hot bath containing the biocontrol agent, Bacillus amyloliquefaciens.
- Other fruit was treated with 1-MCP (Smartfresh™).
- Thereafter, all the fruit was stored at 10°C for eighteen days and allowed to ripen for five days at 25°C.
- Controlled atmosphere storage conditions were used with different combinations of oxygen and carbon dioxide.
- The biocontrol agent was used with biodegradable packaging and different plastic film types to investigate the influence of modified atmosphere packaging (MAP) on fruit quality.
Outcome of study and benefits to industry
- The use of 1-MCP is recommended to the industry, since its application indicated potential to control mango post-harvest diseases. This increases market penetration.
- Francois van Deventer, an MSc student that was involved in the project, has submitted a paper on the work. Francois is graduating in April 2012, Cum Laude, and is currently employed by an agribusiness company, Syngenta. The project was therefore successful in capacity building.
- Dr Eva Arrebola completed the in vitro studies for Bacillus amyloliquefaciens – results were published in the journal, Crop Protection (2009).
- One more paper was published as an outflow of the work: Sivakumar, Van Deventer, Terry, Polanta, & Korsten (2011). Journal of the Science of Food and Agriculture.
