RESULTS OBTAINED BY PRUNING OVERCROWDED AVOCADO ORCHARDS

SUMMARY A large percentage of avocado orchards in South Africa are currently in an overcrowded state. Trees in these orchards have become so tall that they are difficult to spray or harvest. Results show that orchards in the initial phase of congestion can be selectively or mechanically pruned without adversely affecting yield. Trees that are already in a seriously congested condition have developed bare stems at their base with most of the foliage in the treetops. These denuded areas can be rehabilitated by more drastic pruning actions but without the need to staghorn the trees. When drastic pruning is fully applied immediately after harvest, one year’s yield will, however, be lost. A pyramidal tree shape is preferred in order to get an open V-shape in the work row. The tree height must not exceed 80% of the row width and possibly less where the work rows are not strictly north-south orientated or where the trees are on a slope. Current research is not only examining post-harvest pruning but also the correct follow-up summer pruning that needs to be applied. A complete orchard management program is essential to support the pruning actions so that controlled growth can take place, and production and fruit quality optimized. Additional advantages from a pruning program include more uniform and smaller trees where orchard operations and spray activities will be easier and cheaper.