- T Botha, G C Schutte, J H Lonsdale en J M Kotzé
- University of Pertoria, Pretoria 0002
- 1988
n Groot verskeidenheid swamme (nege genera insluitend giste) is uit die twee lietsjiekultivars gei’soleer. Effektiewe beheer van na-oesbederf by die Mauritius-kultivar is verkry met prochloras, prochloras & TBS, prochloras & imasalil en imasalil & TBS doopbehandelings (1 000 dpm vir 10 minute). Prochloras het egter ‘n onaanvaarbare bysmaak in die lietsjies tot gevolg gehad en daarom het die imasalil en TBS-behandeling tans as die enigste alternati ef oorgebl y. Verpakking van liets/ies in poli-etileensakke het verbruining vertraag en massaver/ies verminder. ‘n Grater mate van na-oesbedert het egter by poli-etileenverpakte vrugte voorgekom. Die graad van vrugteverrotting was gekorreleer met die graad van vrugtevliegskade op die lietsjies. Beheer van vrugtevlieg is ‘n belangrike en integrate komponent van ‘n strategie vir die beheer van na-oesbederf. By die kultivar Madras het die imasalil & TBS-doopbe-handeling oak die beste gevaar, maar die resultaat was swakker as in d ie geval van die vroee kultivar. Die beroking en ULV-behandelings het swak gevaar en die swael-behandeling het ‘n swae/smaak in veral Madras-vrugte tot gevolg gehad. Die swak resultate by die kultivar Madras word aa n swak kultivareienskappe toegeskryf.
Summary:
- Multiple genera of fungi, including yeasts, are responsible for postharvest decay in litchis, with species isolated from ‘Mauritius’ and ‘Madras’ cultivars.
- Effective fungicide dip treatments for controlling postharvest decay in the ‘Mauritius’ cultivar include prochloraz, prochloraz & thiabendazole (TBS), prochloraz & imazalil, and imazalil & TBS; however, prochloraz leaves an unacceptable aftertaste.
- For practical use, imazalil & TBS are the preferred fungicide treatments due to better taste and effectiveness.
- Polyethylene packaging delays fruit browning and reduces weight loss but can increase fungal decay due to moisture retention.
- Postharvest decay correlates strongly with fruit fly damage; 98% of yeast-related decay occurred in fruit with fly lesions, indicating the critical importance of fruit fly control in decay management.
- The ‘Madras’ cultivar showed poorer fungicide treatment results; sulfur treatments caused undesirable off-flavors, and fumigation/ULV treatments were ineffective.
- Postharvest management recommendations include:
- Rigorous fruit fly and insect control to prevent infections.
- Use of fungicide dip treatments (imazalil & TBS being optimal).
- Polyethylene packaging to minimize browning and weight loss, with caution due to decay risk.
- The study emphasizes collaboration between researchers and producers to improve the postharvest quality and exportability of South African litchis.
- This research supports efforts towards reducing postharvest losses, maintaining fruit quality, and enhancing market competitiveness of litchis.