126 



N. H. AGR. EXPERIMENT STATION 



[Bulletin 144 



ments made here indicate that the leaf spot in New Hampshire 

 is of the same origin. 



Treatment. The fact that the 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 



Fig. 24.— Unsprayed tree defoliated by Leaf Spot. 



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 effective for leaf spot. Sprayings made at various times in 

 the summer have had little or no effect upon the number of 

 spots of rot on the fruit at picking time. The destruction of the 

 affected fruit is apparently the only efficient treatment for this 

 form of the disease. All cankered limbs should be cut out and 

 burned. Proper treatment of wounds and thoro spraying will 

 decrease the number of cankers. Heavy applications made when 

 the trees are in a dormant condition are probably especially 

 efficacious. (See page 138.) 



