Jakkie (OPJ) Stander
Citrus Research International | Department of Horticultural Science, University of Stellenbosch
E-mail: jakkie@sun.ac.za
In 2017 citrus producers in the Eastern and Western Cape reported abnormal levels of premature fruit drop in a range of different citrus cultivars. In some orchards fruit drop levels of up to 80% of the total yield were recorded. This report is based on an investigation conducted in May 2017 which considered as many potential contributing factors as possible. It aimed to describe the nature of the fruit drop problem and provide future recommendations.
General Findings
The excessive premature drop of citrus fruit during the 2016/17 season was most likely caused by the development of abnormal stylar-end characteristics in non-‘Navel’ cultivars, and by large secondary navels and navel-end openings in ‘Navel’ orange fruit. Nearly all abscised fruit had a fissure at the stylar- or navel-end of the fruit, and were split open. For ‘Navels’ in the Sundays River Valley (SRV), the majority of fruit still on the trees had large secondary navels and were about to drop, or would most probably have to be culled in the packhouse.