11 



Liquid v. Dust. 



We now have data bearing on the question of the use of 

 dust mixtures for control of fungous diseases and insects which 

 are derived from a period of about six years. Dust has not 

 been able, apparently, to control plant lice, red bug, leaf 

 hoppers, scab or other fungous diseases in a way to compare 

 at all favorably with liquid applications. Dust can, therefore, 

 not be recommended as a substitute for liquid applications on 

 apples. 



Substitutes for Arsenate of Lead. 



Calcium arsenate and other recent combinations of arsenic 

 with minerals, other than lead, have been placed on the 

 market at figures which make them, on the basis of equivalent 

 amounts of arsenic, much cheaper than arsenate of lead. Cal- 

 cium arsenate and such others as the writer has examined 

 apparently break down much more quickly than lead arsenate, 

 and are therefore less safe for use on the foliage and fruit of 

 apple trees, which are not tolerant of arsenic as are potatoes 

 and tomatoes. 



