Entomovectoring technology in kiwifruit pollination

The flowers of Actinidia deliciosa show adaptations to wind pollination, as well as insect pollination. Each female pistil requires about 3000 pollen grains to set 700 seeds per fruit, which is the minimum number of seeds required for a fruit with good market value. However, wind pollination is significantly impeded by the layout of most commercial orchards (e.g., plantation frames, anti-hail nets, plastic covers). Hence, in commercial kiwifruit orchards, successful pollination requires the combined action of entomophilous and anemophilous pollination. With the global decline of wild pollinators, supplemental pollination is frequently implemented in agricultural practices. Honeybees, however, show little attraction towards kiwifruit flowers. As a result, many growers rely on mechanical application of pollen. We aim to compare the efficacy of mechanical devices, insect pollination, and a third system that combines the advantages of the previous two: entomovectoring technology. For the latter, we tested the Flying Doctors system, consisting of a bumblebee colony equipped with a pollen dispenser, allowing a continuous, yet effortless, application of pollen during the blooming season. We performed trials in France in which we tested the activity of Flying Doctors hives, the amount of pollen dispersed per hive installed in the field, along with the viability of the pollen in pollen trays over time. Pollination success on fruit set, fruit size and roundness, number of seeds per fruit and fruit weight was assessed. Our results show the advantages of entomophilous compared with wind pollination and dusting. The use of the Flying Doctors technology gave the best results in terms of fruit weight and number of fruits of high market value, while reducing overall pollen use by 80% compared with mechanical blowing of the pollen as currently practiced.