BOARD OF HORTICULTURE 



117 



in tlie tops of the trees, because in the upper portion completeness of covering 

 is often nearly impossible because of the height of the trees. Growers have not 

 adoptetl the use of towers as rapicily as the jjrowth of the trees demanded. 

 Immediate improvement ahvays results where one man is put to working on top 

 of the tank or on a tower whenever mature trees must be sprayed with the ordi- 

 nary outfits. Another help to better spraying that has been adopted by a good 

 many growers, in tlie last year or two especially, is the use of copperas or iron 

 Sulfate added to the ordinary lime-sulfur after the latter has been put into the 

 tank. This results in a chemieal action wliich does not destroy the practical 

 effectiveness of the spray, although it turns it black in color. The black color 

 makes it possible for the sprayer to see at once just where his spray hits and 

 whether it is in the form of a fine mist or of coarse particles, etc. He can do a 

 better and more thorough job, because he can see what he is doing. His hired 

 sprayers also will do a better job, for he can teil just what sort of work they 

 are doing. 



APPLE SCAB ON FRUIT 



One more Suggestion may be made. It is well known that if the old leaves 

 in an orchard are completely turned uuder during the winter and before the buds 

 begin to unfold in the spring, the amount of initial scab infection will be greatly 

 reduced. In thö" Hood River Valley this method lias been tested occasionally 

 with very little evidence of effectiveness, but that is doubtless because, surrounded 

 on all sides by other orchards not similarly handled as they were, the test blocks 

 suffered from the abundant entrance of scab spores from without. In sections 

 where the orchards are more isolated the practice of plowing the old leaves 

 under should be practiced where the soil conditions and weather conditions will 

 permit. Where there is a cover crop growing vigorously in the orchards, such as 

 alfalfa or clover, it is thought by some that the overlying blauket of the cover 

 crop may prevent to some extent tlie successful passing of spores discharged from 

 the old leaves up into the air of the orchard. At any rate experience has shown 

 a decrease in scab trouble where cover crops have become general, perhaps, how- 

 ever, only because better spraying methods have gone band in hand with general 

 improvement in orchard practices. 



