DISEASES OF THE PEAR 



247 



The pear blight is the result of the work of bacteria. The 

 bacillus multiplies very rapidly under favorable conditions. 

 The nectar in the flowers offers a very good medium on 

 which to develop. From this source it is usually carried 



Fig. 109. — Fire blight of the pear on the twig. (After Whetzel and Stewart, 

 Cornell Agricultural Experiment Station.) 



from one plant to another by insects visiting the different 

 flowers. 



The control of the blight is only accomplished by system- 

 atic and careful pruning. It may even be eradicated by 



