DISEASES OF THE APPLE. 239 



treatises which are easily obtainable, such as Experiment Sta- 

 tion Bulletins, etc. 



BITTER ROT. 



Cause: Bitter Rot is caused by a fungus {GlomereUa rufoma- 

 Gulans) which attacks, not only the apple, causing Bitter Rot, 

 but also the twigs, causing Bitter Rot Canker. 



Description: The disease is first noticed as a small circular 

 spot on the unbroken skin of the apple. Later, as the spot en- 

 larges, it becomes a pale brown with a dark surrounding circle. 

 Sometimes around all is a purple stain. The tissue becomes 

 slightly shrunken, and in the center the fruiting pustules are 

 formed. The entire fruit never becomes covered with these, 

 as in the case of Black Rot. The disease begins sometimes 

 when the fruit is not yet half grownbut is much worse as the fruit 

 reaches maturity. The first outbreak usually occurs about the 

 middle of July. The disease has not as yet done much damage 

 in Nebraska, but' its appearance in a destructive form may be 

 looked for at any time. It has been definitely shown that in 

 some cases the disease passes the winter in the form of cankers 

 on the limbs or twigs of the trees. 



How Spread: The spores wash off during a rain, and in this 

 way reach the apples below. They may also be carried some 

 distance by the wind. The disease is also spread to some ex- 

 tent by insects. 



Treatment: All cankered limbs should be removed and 

 burned, and all affected fruit should be destroyed. The disease 

 can be checked by the early use of a Bordeaux mixture spray, 

 while the apples are young. 



BLIGHT. 



Cause: Apple Blight, sometimes called Twig Blight or Fire 

 Blight, is the result of the growth of bacteria {Bactirium amy- 

 lovorum) in the young and tender twigs of the tree causing the 

 destruction of the cells attacked. 



Description: The disease attracts the attention of the casual 

 observer first by the fact that the twigs at the ends of the limbs 

 are dying, presenting an appearance very much as if they had 



