Between 15 and 20 million bags were applied to individual apples on trees in Washington State and British Columbia in 1994. They were mostly on Fuji apples, but some Jonagold and Mutsu were also bagged. Bags have been used on fruits in Japan for at least 20 years, perhaps much longer.
Japan is a rather difficult place to grow temperate-zone fruit.
To combat the problem, someone had the idea of putting a paper bag over the fruit in the early stage of development and allowing the fruit to grow within the bag's protective environment until near harvest or, with some fruits, right up to harvest. The technique of bagging hasn't been limited to apples, either. There may be more than a hundred sizes and types of bags in Japan. Some are made of a cellophane-type material that allows light on the fruit but keeps off the rain. Some bags are impregnated with fungicides and, possibly, insecticides, although no bags imported into the United States are impregnated with pesticides.