The large cankers at the bases of young trees, frequently re- 

 ferred to by growers as " collar rot " (Fig. 14) are in many cases 

 very probably due to the same cause as that of the cankers on 

 the upper parts of the tree. The well known " collar rot " of 

 King trees may also be due to the same or a similar organism. 



History and Distribution op the Blight Canker. 

 The blight canker has been known for many years and was 

 probably first observed by horticultural writers as early as 1780. 

 It has been repeatedly referred to in horticultural writings 

 since that time, altho its true nature does not seem to have been 

 suspected until 1880. In that year Professor T. J. Burrill, of 

 the Illinois State Experiment Station, while working on the fire 

 blight of pears and apples, came to the conclusion that the so- 

 called " sun scald " spots on the bodies and larger limbs of apple 

 trees are due to the same cause. At a meeting of the Illinois 

 State Horticultural Society in 1881, in answer to a query regard- 

 ing the nature of " sun scald," he said : " The sun scald on apple 

 trees is the same as pear blight." Upon what experimental 

 evidence, if any, this and other statements were based I have so 

 far failed to discover. A number of writers since that time have 

 referred to these cankered patches as " body blight " due to 

 attacks of Bacillus amylovorus, but none seem to have actually 

 produced the cankers by the introduction of the bacteria into 

 the bark of healthy trees. Much of my work has been to try 

 to prove that these cankers were due to pear blight organ- 

 isms. In Saratoga county and vicinity, the disease has been very 

 bad. At least ninety-five per cent, of the young trees which 

 were just coming into bearing were affected with this canker. 

 It is a dangerous pest for the very reason that it affects the 

 trees just at the time that the grower may expect some reward 

 for his labor. In an orchard of about 400 trees (Fig. 15) there 

 were not ten trees out of one hundred still alive that were entirely 

 free from canker and finally the entire orchard was destroyed 

 alth^o it was given the best of care. There are also sections in Cen- 

 tral New York and Jefferson county where orchards are affected 

 as bady as those in the Hudson River valley (Fig. 16). I believe 

 the disease is common thruout the State, as well as in numerous 



