Sequential introduction of honeybee colonies and doubling their density increases cross-pollination, fruit-set and yield in 'Red Delicious' apple

The 'Red Delicious' apple exhibits full self-incompatibility, therefore its fruit production depends totally on cross pollination, especially by honey bees, which are the ultimate apple pollinators. In the present study, the t echnique of sequential introduction of honeybee colonies and doubling their density was applied to determine effects on yield. In three consecutive se ason it was found that sequentially increasing the density of colonies in t he apple orchards from 2.5 colonies per ha., as recommended previously, to 5.0 colonies per ha, and introducing them sequentially (half at the 10% ful l bloom (FB) and half at FB), increased the number of bees per tree, their mobility among the rows, and the proportion of "topworkers" compared with " sideworkers". It seems that a large number of foragers per tree directly in creases the amount of pollination, high bee mobility between rows increases the amount of cross-pollination, and a high proportion of "topworkers" inc reases pollination efficiency. All the above effects were expressed in high er fruit set and higher yield (50-100%) in the treatment plots.