392 Slate Horticultural Society. 



eastern shore of Maryland, and in the James River county of Virginia. 



Since the publication of Mr. Waite's note there have appeared two 

 brief but important reports on this apple canker. These are both by Mr. 

 W. Paddock, of the Xew York State Experiment Station at Geneva, and 

 are published in the numbers of Science for October 28 and December 

 9, respectively. Mr. Paddock began experiments with this disease last 

 spring, it having been called to the attention of the horticultural force at 

 Geneva by orchardists in western N^ew York, who have suffered severely 

 from its ravages. 



Mr. Paddock gives the following symptoms of the trouble: "'This 

 disease attacks the bark of the larger limbs, where all stages of develop- 

 ment may be seen, from small sunken areas to the large cankers of many 

 inches' extent. In aggravated cases a portion of the wood is laid bare. 

 The bark becomes swollen and rough in all directions from the wound, 

 so that the diseased limbs become quite conspicuous. These wounds 

 produce an effect similar to girdling, and where many limbs are attacked 

 the effect on a tree is disastrous." Unless one looks closely, the general 

 appearance of the disease is something like what is commonly known as 

 "body blight." The bark on the limbs or even on the trunk becomes 

 black, and sometimes finally falls away. What seems to be the same 

 disease, sometimes attacks trees near the ground and girdles them therv3. 

 A limited number of observations seem to show this manifestation rather 

 more common on Kings. Spitzenberg, which is known to be an un- 

 healthy tree, is probably sometimes or often killed in the same way. Mr. 

 Waite found the disease in western jSTew York particularly severe on 

 Twenty-Ounce, while in the south Early Harvest was worse affected. 

 Further investigation will doubtless show that other varieties are specially 

 susceptible, while certain ones enjoy relative immunity. 



Mr. "Waite reported that he had found a common fungus, Schizophyl- 

 lum commune, on the dead trees, and thought that perhaps it was the 

 cause of the disease. Mr. Paddock's subsequent experiments have 

 reached a different conclusion, however. He finds that the apple canker 

 is caused by a well-known fungus, Spaeropsis malorum. This is the 

 same fungus which has long been recognized as the cause of black-rot on 

 the apple fruit (not scab). Eurther experiments have shown that the 

 same fungus produces canker upon pear and quince. In his note Mr. 



