64 MANUAL OF FRUIT DISEASES 



Jonathan, Smith and Ben Davis. Among the more resistant 

 varieties are the Baldwin, Yellow Newtown, Grimes, Arkansas, 

 Maiden Blush, Stayman Winesap, Yellow Transparent and 

 Winesap. 



Apple-rust has been known to scientists for about a century. 

 Important studies were made in New England about 1880. 

 Since that date the rust has attracted more than usual atten- 

 tion in the states of Vermont, Iowa, Indiana, Alabama, Ne- 

 braska, West Virginia, Virginia, Kansas and North Carolina. 

 The disease is now found to be widely distributed through the 

 central and eastern portions of the United States. 



The extent of the injury to apple-foliage is not always severe, 

 but sometimes no less than 25 per cent of the leaves is taken 

 from the tree. In many sections of the country the disease is 

 serious on the fruits of the apple. The lesions not only mar 

 the appearance of the fruit, but there is frequently a reduction in 

 size and in quality. Rusted fruit is very likely to become in- 

 fected with storage-rot pathogenes, thus entailing considerable 

 loss. Rust itself does not induce trouble in storage. The 

 red cedar is not only severely injured, but in extreme cases is 

 killed. Where the tree is used for ornamental purposes this 

 becomes an economic item. It is clear, then, that apple-rust 

 may become important in one or more of the following ways : 

 (1) by defoliating the apple ; (2) by dwarfing and reducing the 

 quality of the fruit; and (3) by incurring damage to the red 

 cedar. 



With respect to the amount of the losses resulting from this 

 disease it may be pointed out that in 1912 the crop of York 

 Imperials was an entire failure in many orchards of West 

 Virginia. Actual fruit-losses ranging from $2000 to $3000 an 

 orchard, due to rust, were very common throughout the east- 

 ern part of the state that season. The growers of one county 

 lost $75,000. The disease is equally destructive in Virginia, 

 Alabama, Iowa and Nebraska. 



