BLOTCH 167 



the weather is dry during the early part of the season and wet 

 at the last part, a single late spraying may give better results 

 than two or three early ones. 



With varieties of either pears or apples which are especially 

 susceptible to scab, it is desirable to make two applications before 

 the blossoms open. One of these is made before the blossom buds 

 and the clusters separate from each other ; and the second is made 

 just before the blossoms open. (See Fig. 88). 



Rust. — Similar forms of this disease attack the apple, pear 

 and quince. It is one of those peculiar diseases which at one 

 stage lives on one host plant and at another stage on another 

 host. In this case the second host, with all three forms of the 

 disease, is the cedar tree. On this it forms the peculiar rough 

 brown knots known as ' ' cedar-apples, ' ' and the first thing to do, 

 where possible, is to get rid of the cedar trees. 



On apple leaves the rust appears as small roughened spots, 

 generally in the form of a distinct ring. The tissue of this ring 

 is thickened and on the under surface of the leaf there are 

 numerous little protuberances, while on the upper surface the 

 tissue turns yellow and finally a bright orange. On the fruit 

 the disease is less conspicuous, but appears about the same as on 

 the under surface of the leaves. 



Varieties of fruits differ greatly in their susceptibility. 

 Among apples the Wealthy is conspicuous for its liability to the 

 disease, and the bright orange spots will be found on the leaves 

 of this variety if the disease is in the neighborhood. 



When the disease cannot be controlled by destroying the 

 cedar trees, the only thing to do is to resort to spraying and the 

 same applications given for the scab are a.s effective as any and 

 will do something to keep this disease in check. It is much more 

 troublesome in southern sections than farther north. 



Blotch. — This is a relatively new disease and is much more 

 common in the Middle West than elsewhere, but is sometimes 

 found in most apple sections. It resembles the scab verj^ closely 

 and is often mistaken for it, but on the fruit it is apt to be 

 scattered rather uniformly over the entire surface, while the 

 scab is confined to one side of the fruit. The blotch also makes 

 a less compact growth on the areas affected. It produces cankers 



