342 MANUAL OF FRUIT DISEASES 



fortunately for all concerned, the one is confined to the eastern 

 part of the country, while the other (see page 345) occurs only 

 on the Pacific Coast. They are accordingly named eastern 

 rust and Pacific Coast rust. 



The rust disease here considered is very similar to the apple- 

 rust (see page 63). As already indicated, this trouble has a 

 wide range over the United States east of the Mississippi 

 River. It has been recorded from Connecticut, Massachusetts, 

 New Jersey, North Carolina, Alabama, Mississippi, Indiana, 

 Wisconsin and Iowa. It is relatively rare in New York State. 



Rust is destructive in that it interferes with the normal 

 activities of the plant. In severe cases defoliation results. 

 Affected fruits are rendered worthless, and are usually less than 

 one-half normal size. Several Japanese varieties of pears are 

 likely to be injured. The Worden, Bartlett, Bosc and Duchess 

 are said to remain relatively free from the disease. 



Symptoms. 



Leaves and fruits (Fig. 94) are rusted. In June, orange- 

 colored or dark-brown spots with red borders appear on the 

 upper surface of the foliage. These lesions measure from 

 one-fourth to one-half of an inch in diameter. Toward fall, 

 in August and September, the lower surfaces of the leaves 

 exhibit at first dark spots, which lack a red border, and soon 

 develop finger-like cups in clusters. This is known as the 

 cluster-cup stage of the rust fungus. Fruits are affected from 

 the time when they are no larger than a pea (Fig. 94). The 

 cups already mentioned for leaves develop anywhere on the 

 fruit, although they are more common near the stalk end 

 (Fig. 94). They are orange-colored and possess fringed mar- 

 gins. As a result of the affection, fruits are dwarfed (Fig. 94). 

 These symptoms may also show on the apple and hawthorn, 

 but less commonly than on the pear. Another stage of the 

 fungus occurs on the red cedar. Galls are produced ; they are 

 an inch or less in diameter, very irregular surfaced, being marked 



