The role of honeybees in pollination of apples

Abstract

Considering the relatively high concentrations of airborne apple pollen in apple orchards at flowering time, the present study was undertaken to determine the relative roles of airborne and insect borne pollen in the pollination of apples. Enclosing trees of Yates apples, each grafted with a limb of Jonathan, in bee-proof cages caused significant reduction in the number of fruit set, the weight of fruit harvested, and the number of seeds per Fruit as compared with uncaged trees, although airborne apple pollen concentrations were 4.07 times higher inside the cages than outside. Concentrations of airborne apple pollen are greatest in late morning and early afternoon. Flight activity of bees was related to ambient conditions, temperature having a major effect. There appears to be a threshold of flight activity in the region of 13¦C. Ripening and dehiscence of anthers of Yates apple are promoted by higher temperatures and lower humidities.