This section is from the book "Commercial Gardening Vol1", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
Although the gardener may look upon the great majority of insects as enemies, he must not conclude that there are no friends of his in the insect world. There are several, and it may be well to put them on record here.
In the first place the honey bee (Apis mellifica) does an enormous amount of good to the fruit-grower by fertilizing the pistils in the flowers of his Apple, Pear, Plum, Cherry and other fruit crops, thus ensuring a bounteous harvest, if the spring frosts have not interfered with the process of fertilization at a critical period. Whenever the fruit-grower can manage to have a few hives of bees in his gardens he will find it advantageous from a commercial point of view, and apart from the quantities of honey he may take from the hives for his own use or for sale. Bees, of course, are not only valuable for securing the fertilization of fruit trees and bushes of all kinds, but they perform similar good offices for almost every flowering plant. In a lesser degree the Humble Bees (Bombus ter-restris and B. lucorum) also do good work in fertilizing flowers, but they are often charged with taking a short cut to obtain the nectar by piercing the base of the flowers of Broad Beans and Runner Beans, instead of entering by the mouth of the blossoms and thus secure the deposition of the pollen from their bodies on to the stigmas.