Page:Popular Science Monthly Volume 78.djvu/481

Rh

wave of disease. It to-day causes loss estimated at $36,000,000 annually in the United States. New York alone has incurred a loss of $10,000,000 in one year.

The asparagus rust prohibited successful asparagus culture in several states and threatened that industry in California, where the crop occupies yearly over 7,000 acres of land, until means of control were devised by scientific men. The rice smut was recognized in its

 Black shows area of severe infection; round dots, presence of disease prior to 1909; + indicates the spread of the disease during 1909. After Metcalf.