Proceedings of the Washington State Horticultral Association
Artificial pollination of apple blossoms on a commercial basis was started in the State of Washington approximately 20 years ago. Since that time many orchards with inadequate pollination by natural means have been pollinated artificially; these for the most part produced greatly increased crops as a result of the practice. In general the increase was greatest where pollination by natural means was poorest. The need for artificial pollination was and still is mainly with apples, although some attention has been given to pears, sweet cherries and plums in recent years.
Bullock, R. M. and Snyder, J. C., "Some Methods of Tree Fruit Pollination" (1946). Bu. Paper 2.
Available for download on Saturday, January 01, 2050