Kiwifruit pollination: an unbiased estimate of wind and bee contribution

The role of wind and bees in kiwifruit (Actinidia deliciosa (A. Chev.) C.F. Liang et A.R. Ferguson) pollination was investigated using large cages enclosing 80 mature vines and assembled so as to prevent insects entering without reducing wind flow within the cages. Monitoring wind speed within the cage and in the open orchard showed that the cages were suitable for such experimentation. Cages without hives, cages with hives, open pollination with hives, and hand pollination were compared during 1990 and 1991. Wind pollination led to an appreciable fruit set (81 and 98% in the first and second year respectively) but fruit weight was low, averaging 61 and 66 g. The use of hives resulted in 98-100% fruit set, but fruit size did not improve significantly, remaining far below that achieved by hand pollination (66 g versus 108 g, the first year; 78 g versus 119 g, the second year). The short flowering period, the frequent adverse weather conditions, and the unpredictable foraging efficiency of bee colonies, made both wind and honey bees inadequate for kiwifruit pollination. Only hand pollination guaranteed maximal fruit size in each year.