256 Diseases of Truck Crops 



the total annual production of these oils to be 600,000 

 pounds, 250,000 of which are produced in the United 

 States. Peppermint and spearmint are grown in 

 Wayne County, New York, and in a few northern 

 coimties of Ohio, Maryland, and Indiana. Accord- 

 ing to the Thirteenth Census of the United States 

 the 1909 area devoted to mint in America was es- 

 timated at 8,195 acres. The total crop was valued 

 at $253,000. Of the States growing most on a com- 

 mercial scale may be mentioned Indiana, Michigan, 

 New York, and Tennessee. 



DISEASES OF THE BALM {Melissa officinalis) 



Rust 



Caused by Puccinia mentha Pers. 



The disease attacks about thirty-five members of 

 the mint family. AH the three stages i: e., aecidio- 

 spores, uredospores, and teleutospores, occur on the 

 same host. The disease is characterized by brown 

 sori which are at first cinnamon colored and later 

 chestnut brown. Diseased leaves curl and dry up. 

 The disease is not sufficiently important to warrant 

 treatment. 



Leaf Spot 



Caused by Septoria melisscs Desm. 



The disease is characterized by numerous brownish 

 spots which are angular and apparently limited by the 



