Apr'l, 1912.] SOME APPLE DISEASES — TREATMENT. 19 



and 25.) Trees thus robbed of their fohage from year to year 

 must eventually become greatly impaired in their vigor. 



Fig. 22. — Early stage of Leaf Spot. 



The cause of the leaf spot has occasioned no little difficulty. A 

 number of fungi have been found to be present in the spots, but 

 inoculation experiments have indi- 

 cated that Sphoeropsis Malorum is 

 probably the only one that is of 

 importance in the production of 

 the disease. 



Treatment. The fact that one 

 fungus is responsible for three 

 different forms of disease makes 

 its destruction a matter of special 

 importance and rather unusual 

 difficulty. Spraying has been 

 quite effective in controlling the 

 leaf spot. In the summer of 1908 

 the per cent, of leaves spotted in 

 the orchards referred to under 

 apple scab was reduced from 97 

 to 26 by the use of Bordeaux 

 and to 21 by the use of lime-sulfur solution. Five sprayings 

 were made, but it is probable that only the first three were 



Fig. 23. — Late stage of Leaf Spot, show- 

 ing growth in the size of the spots. 



