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The one a bacterium 

 (Bacillus amylovorus, Burr.), 

 which, in the old cases of 

 blight, winters over in the 

 blighted parts. From these 

 diseased parts a watery exu- 

 dation at times takes place in 

 the spring, which is visited 

 by insects, and by them 

 transmitted to the opening 

 blossoms or to the sap vessels 

 of the tree. Once within the 

 tissues of the host, the 

 microbe may spread indefi- 

 nitely. 



Another cause, producing 

 a similar appearance, has 

 been traced to the presence 

 in the ground of a mould 

 which grows on the surface 

 roots and spreads over them 

 web fashion, thwarting their 

 growth, with the results de- 

 scribed. 



In the first instance, 

 spraying early, to keep off 

 inoculating insects, confines 

 the trouble to a few trees 

 only, and may also disinfect 

 the infested exudation. All 

 blighted parts should be 

 carefully cut off below the 

 lowest manifestation, and 

 burnt each autumn. A 

 good precaution is to disin- 

 fect the knife, after cutting- 

 through a diseased spot, by 

 dipping in carbolic acid. 



Cultivate thoroughly and 

 fertilise liberally, to help the 

 trees to throw off the 

 disease. 



In the second instance, 

 the ground should be deep- 

 ly ploughed, thoroughly 

 drained, and liberally limed and manured, so as to encourage 

 the growth of the roots in healthy surroundings. (See Pear 

 Blight.) 



Powdery Mildew of the Apple. 



