338 MANUAL OF TREE DISEASES 



with the elunination of the spore-producing material in the 

 vicinity of the tree. All the leaves from affected trees should 

 be carefully raked together and burned. Following this, all 

 dead or cankered twigs and branches should be pruned from the 

 tree and burned. This is a tedious operation and unless care is 

 taken many infected twigs will be missed. The twigs that are 

 overlooked become apparent as soon as the leaves are out in the 

 spring and should be removed at that time. The twigs left 

 until that time, however, have had a chance to disseminate 

 spores and start the primary infection of the leaves. If these 

 sanitation precautions are thoroughly carried out for all the 

 sycamores and oaks in the vicinity, the amount of primary in- 

 fection may be considerably reduced, or under adverse weather 

 conditions entirely eliminated. However, since the greatest 

 damage probably comes from secondary infection, spraying with 

 bordeaux mixture is advised to protect the leaves. When 

 spraying has been tried, this disease has been successfully con- 

 trolled. Bordeaux mixture (4-4r-50 or 5—5—50) applied thor- 

 oughly with a power sprayer, so that all the leaves are covered, 

 will prevent the spores that may be present from infecting the 

 leaves. The number and time of the applications depend on 

 the weather conditions. The first application should be made 

 after the buds burst and before the leaves are half grown. A 

 second application should be given about one week later and 

 the third and fourth if the season is rainy, at intervals of two 

 weeks. For fuller directions on spraying trees, see page 357. 



References 



Soiithworth, E. A. A disease of the sycamore. U. S. Dept. Agr. 



Rept. Com. Agr. 1888 : 387-389, pi. 15. 1889. 

 Southworth, E. A. Gloeosporium nervisequum (Fckl.) Sacc. Jour. 



Mycol6gy 6 : 51-52. 1889. 

 Bdgerton, C. W. The physiology and development of some anthrae- 



noses. Bot. Gaz. 45:367^08, pi. 11, figs. 1-17. 1908. 

 Duggar, B. M. Anthracnose of sycamore. In Fungous diseases of 



plants, pp. 278-280. 1909. 



