62 MANUAL OF FRUIT DISEASES 



cline by the first of July, and no spores are disseminated after 

 the last of August. After this season of the year the history 

 of the pathogene on the leaves and fruits is unknown ; but it 

 is believed that these organs do not carry the fungus through 

 the winter and hence are not sources of the first inoculum in 

 the spring. . It is on the twigs that the organism hibernates, a 

 fact of great importance in dealing with the pathogene. 



Control. 



Since the disease characteristically occurs annually, control 

 measures should be applied each year. There are two lines of 

 remedial procedure : the removal of the cankered twigs and 

 the protection of the susceptible parts by spraying. Careful 

 pruning will remove a large portion of the diseased twigs, 

 which are the source of trouble. Their removal is a valuable 

 operation supplemental to the application of a protective spray. 

 Spraying must be done before inoculation takes place; this, 

 as has been seen, occurs within a month after the petals fall. 

 The number of applications depends on the nature of the 

 weather. In the Middle West and Southwest the schedule is 

 as follows : First application, use bordeaux mixture, 3-4-50, 

 three weeks after the blossoms drop. Lime-sulfur should be 

 substituted for bordeaux mixture in wet weather, since the 

 latter produces injury to the fruit and foliage under such con- 

 ditions. Second application should be made two to four weeks 

 after the first. A third application is recommended ten weeks 

 after the petals fall. The second and third applications corre- 

 spond to those made for bitter-rot, so that one course of spray- 

 ing will suffice for both diseases. 



REFERENCES 



Scott, W. M., and Rorer, J. B. Apple blotch, a serious disease of 

 southern orchards. U. S. Agr. Dept. Plant Indus. Bur. Bui. 

 144 : 1-28. 1909. 



Lewis, D. E. The control of apple blotch. Kansas Agr. Exp. Sta. 

 Bui. 196 : 520-574. 1913. 



