SPKAYING WITH FUNGICIDES. 



43 



taken in weighing the proper amount of chemicals. The custom of 

 guessing at the amounts invariably results in a poor mixture. Stock 

 solutions of the copper sulphate, 1 or 2 pounds to the gallon, can be 

 made and kept without deterioration, evaporation being considered. 



(b) On the thoroughness with which spraying is done.— Only nozzles 

 which throw a fine spray should be used. The Yermorel is the stand 

 ard nozzle for good work. In spraying, the old precept that all parts 

 of a tree should be reached by the spray holds good. With a fungus 

 like that of the bitter rot, where a large number of spores may reach 

 a fruit, thorough spraying alone will be effective. The apparent 

 failure to control the bitter rot in many instances is doubtless due to 

 the fact that even with the best spraying it is impossible to cover the 



Fig. 9.— Arrangment of vats used in making Bordeaux mixture. 



entire fruit with the fungicide. Numerous fruits were found on 

 sprayed trees where the fungus had started to grow between points 

 on the fruit covered with the fungicide. It is very desirable that 

 further information concerning the number of sprayed fruits actually 

 rotted be obtained. 



(2) Is winter treatment of the dormant trees of any assistance in the 

 process? — The spraying of trees before the buds opened showed no 

 apparent benefit. This, however, ought not to be taken as conclusive, 

 especially in view of the recent discovery of a stage in the life history 

 of the bitter-rot fungus in the wood and bark of the apple tree. In 

 the absence of any data as to the exact time when this bark stage— the 

 canker — is reached, it may be that winter spraying will to some extent 

 check the development of possible cankers. 



