The contribution of pollinators in the pollination of pome fruits

Pome fruit production is of high economic importance for the Flemish horticulture sector. In Belgium there is a yearly production of around 285.000 tonnes apples and 369.000 tonnes pear. The main cultivars that have been growing over the years are the pear ‘Conference’ and the apple ‘Jonagold’. Earlier studies indicated that more and/or better fruits will be produced when the cultivars are cross-pollinated. To ensure this, pollinizer cultivars are planted within the orchard, and pollinators such as honeybees (Apis mellifera L.), bumblebees (Bombus spp.) and solitary bees (Osmia spp.) can be introduced in apple and pear orchards. The recent declines in the honeybee populations worldwide together with their poor pollination service during cold periods urges to explore the use of other insect pollinators to fulfil and guarantee optimal fruit set. The attractiveness of apple and pear flowers for pollinators is determined by the flower characteristics such as morphology and the quantity and quality of the nectar and pollen. To improve the pollination efficiency and increase yield stability and fruit quality of apple and pear this study will investigate a range of specific measures. First of all, the current pollinator community in apple and pear orchards nowadays will be investigated based on standardised transect walks. Later on the pollinator community will be diversified with managed honeybee and bumblebee hives and the effects on pollination success, fruit set and fruit quality will be measured. Furthermore, we will evaluate the relationship between flower characteristics (nectar, pollen and morphology) and the visitation rate of pollinators in different apple and pear cultivars. The quantity and quality of the nectar of several apple, pear and sweet cherry varieties will be analyzed to make a comprehensive comparison in relation to pollinator preferences. The obtained preliminary results of this study will be discussed in this presentation.status: publishe