BITTER ROT 199 



Twig Blight. — Pears, apples and quinces are subject to attacks 

 of a bacterial disease known as twig blight. Small twigs of trees 

 are seen to turn brown after the leaves have formed. This may 

 prove very serious, as the attacks may extend into the larger 

 branches and destroy nearly all the new growth each season. No 

 satisfactory remedy for this disease has yet been found. Spraying 

 with Bordeaux mixture for the control of scab and other diseases 

 will doubtless aid somewhat in the control of twig blight. 



Severe pruning is considered the most satisfactory remedy. 

 The pruning instruments should be disinfected after every cut by 

 dipping in an antiseptic solution, such as copper sulfate, or carbolic 

 acid. Make the cuts about one foot farther back than the disease 

 because of the probability that the disease extends downward in 

 the sap farther than it shows on the surface. Burn the prunings. 



Fig. 124. — Scab disease and sooty blotch on apples compared with Bound specimens on the 



left. (Ohio Station.) 



Constitutional remedies are sometimes recommended. It is 

 believed that the disease is more prevalent in heavy, rich soils. If 

 this be true, robbing the soil of some of its plant food by cropping 

 with millet, buckwheat and similar crops may be helpful. 



Certain varieties are more immune to the disease than others. 

 Further study along this line is yet to be made. 



Bitter Rot. — The apple fruits are attacked by a disease known 

 as bitter rot. The fungous growth starts in a small spot on the 

 surface when the fruit is growing on the tree. These spots enlarge 

 until they cover large areas and reach to the center of the apples. 

 Several spots blend into each other and the whole fruit is finally 

 destroyed. Certain varieties of sweet apples are more subject to 

 the disease than others. Bentley Sweet, for example, is quite 

 subject to attacks of bitter rot. 



