- R B Cronie1 and P G Mostert2
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1ARC-lnstitute for Tropical and Subtropical Crops, Private Bag Xl 1208, Nelspruit 1200, South Africa
2Mostert Consulting Service, PO Box 3799, Nelspruit 1200, South Africa - 2005
The South African litchi industry is predominantly export orientated and fruit size is of great importance. Furthermore, litchi yield is affected through alternate bearing. Therefore, an attempt was made to establish a management program to increase litchi yield and fruit size by combining and optimising existing management strategies. Five management programs, which consist mainly of additional foliar fertiliser and plant growth regulator (PGR) applications, were developed and are currently being compared with each other according to their effects on yield and fruit size. No yield or fruit size data is available yet, but will be reported on in the coming season. At the end of this three to five year research, the most successful program will be included in a software program, which should assist the farmer in managing his orchard optimally.
Summary:
- The South African litchi industry is export-oriented, with fruit size being critically important for marketability.
- Litchi yield is affected by alternate bearing, prompting the need for a management program to improve yield and fruit size.
- The research aims to establish a holistic orchard management program combining foliar fertiliser, plant growth regulators (PGRs), and horticultural practices like pruning and girdling.
- Five different management programs were developed, each with variations of additional foliar fertiliser and PGR applications, and are currently compared for their effects on fruit retention, yield, and size.
- The programs include treatments such as extra urea, cytokinins (Kelpak), KNO3 sprays, auxin applications (Maxim), and girdling at different fruit development stages.
- Standard practices across all programs include pruning after harvest, ethephon applications, fertiliser as per control, and pest control for fruit fly and litchi moth.
- Trials were conducted at Hall & Sons in Nelspruit with soil and leaf analysis guiding adjusted fertiliser regimes.
- Environmental factors such as temperature, humidity, soil moisture, and rainfall are continuously monitored, and orchard production mapping is used to track bearing patterns.
- Fruit set is monitored biweekly to weekly, with plans to measure yield per tree and fruit size at harvest by weighing and measuring fruit shoulder width.
- As the trial is in early stages, no yield or fruit size results are yet available; data collection and analysis will be reported after the 2005/06 season.
- The most successful management program will be incorporated into software designed to assist farmers in optimal orchard management.