The Appropriate Management of Honey Bee Colonies for Pollination of Rosaceae Fruit Trees in Warm Climates

Most of the Rosaceae fruit trees, such as apple, pear, plum, almond and cherry, exhibit full self-incompatibility. Therefore, their fruit production completely depends on cross pollination. The ultimate pollen carrier in Rosaceae is the honey bee. In the present review, different bee-hive management techniques for improving fruit set and yield are discussed. The main manipulations are of colony density and the timing and number of colony introductions. In pear, it was found that increasing the density from 2.5 colonies ha -1 to 5 colonies ha -1 in one introduction at 10% full bloom (FB), did not increase bee activity on the trees and did not improve fruit set and yield. However, introducing the colonies sequentially (1.25 colonies ha -1 at 10% FB and 1.25 colonies ha -1 at FB) increased bee activity and consequently improved fruit set and yield. In apple, the combination of both treatments: increasing the density to 2.5 colonies ha -1 at 10% FB and a second introduction of 2.5 colonies ha -1 at FB, for a total of 5 colonies ha -1 , increased the number of bees tree -1 , their mobility between the rows and the proportion of “topworkers” compared with “sideworkers”. As a result, fruit set and yield were enhanced. In Japanese plum, highest bee activity, fruit set and yield, were achieved when colonies were introduced at four different times (multiple introductions). Each introduction was of a density of 1.25 colonies ha -1 at 10% FB, 50% FB, FB and FB+3 days (total of 5 colonies ha -1 ). For all three species, there was a positive and statistically significant correlation between the average number of bees tree -1 and fruit set or yield. The optimum number of bees tree -1 min -1 at FB was 6-7 for pear, 7-8 for Japanese plum and 12-14 for apple.