Feasibility of mechanical pollination in tree fruit and nut crops: a review

Pollination is essential for the production of most fruit and nut crops, yet it is often a limiting factor for both yield and product quality. Mechanical pollination (MP) systems offer the potential to increase productivity of a broad range of horticultural fruit and nut crops, and to manage the risk of reliance on current insect pollination services. To date, commercial MP systems have been developed for only a few crops (e.g., kiwifruit and date palm), suggesting that innovation in the use of MP systems has been stymied. Here, we review published and ‘grey’ literature to investigate the feasibility of MP systems of economically important tree fruit and nut crops. This review found that, whilst MP systems are a commercial reality for a wider range of fruit crops (e.g., sweet cherry) than nut crops (e.g., almond), promising results have been achieved at the experimental scale. Further we identified that the key barriers for progressing MP systems more widely include knowledge gaps in pollination biology, particularly of emerging fruit and nut species that are grown outside their native distributions, and access to proprietorial knowledge gained by commercial operators. What continues to remain unclear is detailed knowledge of the commercial development of MP systems and therefore, the opportunities to apply this knowledge to other tree crops where effective pollination limits yield and quality.