est in those regions of the world where the human population is greatest in relation to the food resource, making this all the more important in addressing the issue of world hunger (McEwen, 773).
Losses from plant diseases can be as great or greater than losses from insects, and the famine in Ireland in the nineteenth century can be cited as an example. This was due to blight which destroyed the entire food crop of the country, and such an epidemic can appear and do its damage quite rapidly. Losses due to disease are an annual occurrence in most of our fruit, vegetable, and field crops, and the extent of this type of loss is also difficult to document with any accuracy. However, models have been developed that suggest what the size of losses could be and what new crop yields might be with the elimination of certain crop diseases. It was recently estimated, for instance, that potential crop losses in the United States for most of the major vegetables, in the absence of protective chemicals, could be quite high--as high as 89 percen
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