Weather (hot or cold/ dry or wet), hail damage, pests and diseases that may limit or impact crop production are more visibly evident factors compared to the influence of the a less marked/ measurable factor of pollination. While self-pollination in macadamias is possible, it may not be as effective as cross pollination in nut set and the use of honeybees has the potential to increase yield.
Fruit set and yield, from inflorescences visited by honeybees to honeybee-excluded inflorescences, were compared between the cultivars ‘695’, ‘814’, ‘816’ and ‘A4’. In this study yields of all four cultivars were considerably higher in inflorescences open to pollination by honeybees than those from which honeybees were excluded (bagged). Only 24.4% of bagged flowers set fruit, while up to 75.6% of open-to honeybee-pollinated flowers set fruit.
All cultivars studied benefited from pollination: nut size increased with between 2 and 6mm, between 6- 75% more nuts were harvested in open to honeybee pollinated inflorescences and shelled-kernel weight increased with between 6-18.6%. The contribution of honeybees can thus be converted into a monetary value to calculate the actual contribution of honeybees to crop yield. This is important information for the rapidly growing South African macadamia industry and goes hand in hand with a growing demand for honeybee colonies for pollination.