New Yokk Ageicultueal Expeeiment Station. 353 



The extent of growth of the Sphaeropses where inoculated has 

 been expressed in the relative terms, slight, fair, good and very 

 good. Figures 1, 2 and 3 of Plate XXXI are reproduced from a 

 photograph of inoculated nursery trees of apple, pear and Jap- 

 anese plum respectively, and show what has been termed a very 

 good growth. Figure 4 of Plate XXXI shows a slight growth on 

 an apple tree, while Fig. 5 is a check apple tree. The other two 

 degrees of growth range between the two shown in the illustration. 



Where the fungus made a very good growth it spread rapidly 

 till the different inoculations coalesced and formed continuous 

 cankers as is shown in the illustration. In some instances 

 pycnidia formed by the tenth of July and by the first of August 

 growth had stopped as could be seen by the formation of a defi- 

 nite boundary between the dead and living bark. Pycnidia were 

 now abundant on the dead bark and occasionally on the decorti- 

 cated wood under the grafting wax as well ag elsewhere on the 

 dead surface. In some instances where the fungus made a less 

 vigorous growth the area of dead bark was entirely covered with 

 the wax. 



A number of the different cultures were inoculated into all four 

 kinds of trees, all but three into both apple and pear trees, while 

 all were inoculated into apple trees. Twenty-five sweet and 

 twenty-five sour cherry trees, and twenty-five European plum trees 

 were also used in the experiment, but none of the inoculations on 

 these trees were effective. In all of the other inoculations there 

 were but two entire failures. But the inoculations made with cul- 

 tures of Sphaeropsis from cankered apple tree limbs made a 

 greater growth than most of the others. Those made with cul- 

 tures obtained from Japanese plum were the only ones which made 

 a comparable growth. 



The results of the inoculations on the pear trees are interesting 

 from the fact that the cultiires obtained from cankered apple tree 



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