An assessment of alternative postharvest technologies for the disinfestation of fresh Cape Flora cut flowers for export from South Africa
Masters Degrees (Conservation Ecology and Entomology)
Huysamer, Anton Jean (2018-12)
Thesis (MSc)--Stellenbosch University, 2018.
ENGLISH ABSTRACT: A successful industry has developed around the export of fresh Proteaceae cut flowers from South Africa. Phytosanitary insects are a barrier to export, as South African Proteaceae associates with a considerable entomofauna. The development of alternative postharvest disinfestation technologies could reduce these interceptions and promote market access. Surveys on export material were conducted to determine which pests are most problematic when exporting Proteaceae. A total of 82 interceptions were made, comprising of eight insect orders and 26 insect families. Although many interceptions were as a result of solitary individuals, multiple interceptions consisted of many individuals of western flower thrips (Frankliniella occidentalis) and protea itch mite (Procotolaelaps vandenbergii). These pests were selected as the key pests on which to focus for disinfestation using alternative postharvest technologies not yet utilised for Proteaceae. Controlled Atmosphere and Temperature Treatment Systems (CATTS) technology was assessed as a potential disinfestation tool for fresh Proteaceae cut flowers. The tested commodities were Leucospermum ‗Veldfire‘, Protea magnifica ‗Barbi‘, Leucadendron ‗Safari sunset‘ and ‗Jade pearl‘, and Geraldton wax ‗Ofir‘ (Myrtaceae). CATTS treatments consisted of temperature ramps of 35°C/hour and 30°C/hour from 23°C to 40°C, with a 15 min soak at 40°C, and 35°C/hour and 30°C/hour from 23°C to 50°C, with a 15 min soak at 50°C, under modified atmospheres of 1% O2, 15% CO2 in N2. Treated stems were subjected to vase life studies after treatment, or following air- and sea-freight storage simulations at 2°C for 3 or 21 days respectively. Leucospermum ‗Veldfire‘ did not withstand treatments, as style wilting reduced overall quality. Protea magnifica ‗Barbi‘ withstood some treatments, maintaining comparable quality to control stems in the vase immediately after treatment. Both Leucadendron commodities withstood treatments well, and maintained marketable quality following treatment, air- and sea-freight simulations. Geraldton wax ‗Ofir‘ maintained quality in vase immediately after and following air-freight simulations. CATTS treatments of 35°C/hour and 30°C/hour to 40°C in 1% O2, 15% CO2 in N2 resulted in 100% mortality in western flower thrips and protea itch mites within 24 hours of treatment. Postharvest fumigation treatment with ethyl formate (EF) was also assessed as a potential disinfestation technology. Concentrations ranged from 18.53g/m3 to 151.47g/m3 EF, and durations ranging from 30 mins to 3 hours for the same cut flower commodities listed above for CATTS treatments. Further trials on Geraldton wax ‗Ofir‘ consisted of 10g/m3 and 20g/m3 for 1 and 2 hours. All treatments resulted in reduction in overall quality of treated fresh goods. EF fumigations of 18.53g/m3 for 1 and 2 hours achieved 100% mortality within 24 hours of treatment in western flower thrips and protea itch mites, but excessive post fumigation damage renders EF unsuitable. The information generated from this study has highlighted the most problematic phytosanitary pests in export consignments of fresh Proteaceae from South Africa. It has also highlighted a potential postharvest technology for integration into current disinfestation strategies, and refuted another. This information can assist in the development of postharvest disinfestation strategies, ultimately reducing the phytosanitary pressures and promoting the export of fresh Proteaceae cut flowers from South Africa.
AFRIKAANSE OPSOMMING: n Suksesvolle bedryf het ontwikkel rondom die uitvoer van vars Proteaceae snyblomme uit Suid-Afrika. Fitosanitêre insekte is 'n belangrike handelsversperring, aangesien Suid-Afrikaanse Proteaceae met 'n aansienlike en diverse entomofauna geassosieer word. Die ontwikkeling van alternatiewe na-oesontsmettingstegnologieë kan fitosanitêre insek onderskeppings verminder en marktoegang bevorder. Fitosanitêre opnames is uitgevoer om vas te stel watter peste die mees problematies is met die uitvoer van Proteaceae. Altesaam 82 onderskeppings is gemaak, bestaande uit agt insek ordes en 26 insek families. Alhoewel baie onderskeppings toe te skryf was aan geïsoleerde individue, het verskeie onderskeppings bestaan uit veelvuldige individue van westerse blomblaaspootjies (Frankliniella occidentalis) en protea-kliermyt (Procotolaelaps vandenbergii). Hierdie peste is gekies as fokus spesies vir ontsmetting deur middel van alternatiewe na-oes tegnologie wat nog nie voorheen in die bedryf gebruik is nie. Beheerde Atmosfeer- en Temperatuurbehandelingstelsels (CATTS) -tegnologie is geassesseer as 'n potensiële ontsmettingsmetode vir vars Proteaceae snyblomme. Die produkte wat geëvalueer was sluit in Leucospermum 'Veldfire', Protea magnifica 'Barbi', Leucadendron 'Safari Sunset' en 'Jade pearl', en Geraldton wasblom 'Ofir'. CATTS behandelings het bestaan uit temperatuur-verhogingsskale van 35°C/uur en 30°C/uur vanaf 23°C tot 40°C, met 'n 15 min wekingsperiode by 40°C en 35°C/uur en 30°C/uur. vanaf 23°C tot 50°C, met 'n 15 min weekingsperiode by 50°C, onderhewig aan ŉ gemodifiseerde atmosfeer van 1% O2, 15% CO2 in N2. Behandelde stele is onderworpe aan vaaslewe-studies direk behandeling, of na lugen seevragopbergingsimulasies by 2°C vir 3 of 21 dae onderskeidelik. Leucospermum 'Veldfire' het nie die behandelings goed hanteer nie, aangesien ernstige stylverwelking drastiese algehele gehalte vermindering tot gevolg gehad het. Protea magnifica 'Barbi' het sekere behandelings weerstaan, met die handhawing van vergelykbare gehalte gedurende vaaslewe in vergelyking met die kontrole. Beide Leucadendron-produkte het die behandelings goed weerstaan, met die behoud van bemarkbare gehalte direk na behandeling, asook gevolg deur lugen see-vrag simulasies. Geraldton wasblom 'Ofir' het gehalte gehandhaaf in die vaas direk na behandeling asook na lugvrag-simulasies. CATTS behandelings van 35°C/uur en 30°C/uur tot 40°C in 1% O2, 15% CO2 in N2 het daartoe gelei tot ‗n 100% mortaliteit in beide westerse blomdruppels en protea-kliermyt binne 24 uur vanaf behandeling. Etielformaat (EF)-beroking is geassesseer as 'n potensiële ontsmettings-tegnologie. Konsentrasies het gewissel van 18.53g/m3 tot 151.47g/m3 EF, en het geduur van 30 minute tot 3 uur vir dieselfde produkte wat in Hoofstuk 3 getoets is. Verdere toetse op Geraldton wasblom 'Ofir' het bestaan uit 10g/m3 en 20g/m3 vir 1 en 2 ure. Alle behandelings het gelei tot 'n afname in die algehele gehalte van die behandelde vars produkte. EF-berokings van 18.53g/m3 vir 1 en 2 ure het 100% mortaliteit binne 24 uur van toediening in beide Westerse blomdruppels en protea-kliermiddye veroorsaak, maar weens die buitensporige skade is bevind dat EF nie geskik is nie. Die inligting bekom uit hierdie studie, het die mees problematiese fitosanitêre plae in uitvoerbesendings van vars Proteaceae uit Suid-Afrika uitgelig. Dit het die gebruik van ŉ potensiële na-oes tegnologie vir integrasie in huidige ontsmettings strategieë beklemtoon, terwyl 'n ander afgekeur is. Resultate van hierdie studie kan help met die ontwikkeling van na-oesontwrigtingstrategieë, wat uiteindelik die fitosanitêre druk verminder en die uitvoer van vars Proteaceae snyblomme uit Suid-Afrika bevorder.
Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/104880
Masters Degrees (Conservation Ecology and Entomology) 
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