PLUM DISEASES 373 



Control. 



The customary measures of fruit disease control do not readily 

 apply to silver-leaf. As a matter of fact, no specific schedule 

 for the control of silver-leaf, based upon experimentation, is 

 at hand. Certain precautionary measures should be taken : 



(1) affected limbs, trunks and stumps should be wholly de- 

 stroyed, and brush-piles should never be allowed to accumulate ; 



(2) avoid the use of the limbs or trunks of any of the previously- 

 mentioned fruit-trees as props and posts ; (3) avoid injuries to 

 the roots, and to the trunks and branches ; (4) avoid planting 

 young trees showing brown hearts. 



It has been shown that the application of iron sulfate, as used 

 in New Zealand, is wholly without value in the control of silver- 

 leaf. 



REFERENCES 



Giissow, H. T. Der Milchglanz der Obstbaume. Zeitschr. fur 



Pflanzenkr. 22 : 385-401. 1912. 

 Giissow, H. T. Preliminary note on "silver leaf " disease of fruit trees. 



Phytopath. 1 : 177-179. 1911. 

 Percival, John. "Silver-leaf" disease. Linn. Soc. Bot. Journ. 35: 



390-395. 1902. 

 Aderhold, Rud. Notizen iiber einige im vorigen Sommer beobachtete 



Pflanzenkrankheiten. 4. Milchglanz des Steinobstes. Zeitschr. 



fur Pflanzenkr. 5 : 86-90. 1895. 

 The Duke of Bedford and Pickering, S. U. Silver-leaf disease. Wo- 



burn Exper. Fruit Farm Rept. 12 : 1-34. 1910. 

 The Duke of Bedford and Pickering, S. U. Silver-leaf. Woburn 



Exper. Fruit Farm Rept. 6 : 210-224 ; 234-235. 1906. 

 Brooks, F. T. Silver-leaf disease. Journ. Agr. Sci. 4 : 133-144. 1911. 

 Brooks, F. T. Silver-leaf disease (II). Journ. Agr. Sci. 5:288-308. 



1913. 



POCKETS, OR BLADDERS 

 Caused by Exoascus Pruni Fckl. 



This disease has a very general geographical range in Europe 

 and in portions of the United States. It has been reported 

 from Michigan, Iowa, South Dakota, North Dakota, Ohio, 



