APPLE DISEASES 13 



the fourth applications. Bordeaux mixture has been used 

 widely for the control of apple diseases, and particularly for 

 scab. It has been replaced with lime-sulfur spray and a sulfur- 

 lead dust on account of the injury or russeting of fruit which 

 results from the use of bordeaux (Fig. 124, page 434). 



It has been shown that dusting with properly powdered 

 materials is fully as effective as spraying. The operation is 

 much more rapid in covering the orchard ; an orchard may be 

 dusted in one-fifth to one-tenth the time required for spraying 

 the same. This dusting process not only saves time but an 

 orchard of large acreage may be protected at critical times, a 

 thing not always possible with the slower liquid process. Apply 

 a mixture of ninety parts finely powdered sulfur and ten 

 parts arsenate of lead (powdered), using about one and one- 

 fourth to two and one-half pounds a tree at each application. 

 The smaller dusting machines may be operated by hand, the 

 larger ones by a gasoline engine. The time of application of 

 dust mixtures does not differ from that of the application of 

 sprays. 



REFERENCES 



Wallace, E. The scab disease of apples. Cornell Univ. Agr. Exp. 



Sta. Bui. 335 : 545-624. 1913. 

 Clinton, G. P. Apple scab. Illinois Agr. Exp. Sta. Bui. 67 : 109-156. 



1901. 

 Reddick, D., and Crosby, C. R. Dusting and spraying experiments 



with apples. Cornell Univ. Agr. Exp. Sta. Bui. 369 : 308-356. 



1916. 

 Jackson, H. S. Diseases of pomaceous fruits. Scab. Oregon Crop 



Pest and Hort. Bienn. rept. 1911-1912 : 238-241. 1913. 

 Whetzel, H. H., and Hesler, Lex R. Some of our most common apple 



diseases. Apple scab. In The Fruit Industry in New York State. 



New York Agr. Dept. Bui. 79 : 855-861. 1916. 

 Aderhold, R. Die Fusicladien unserer Obstbaume. Landw. Jahrb. 



25 : 875-914. 1896. 

 Aderhold, R. Die Perithecienform von Fusicladium dendriticum 



(Venturia chlorospora f. Mali). Deut. bot. Ges. Ber. 12:338- 



342. 1894. 



