April, 1912] SOME APPLE DISEASES TREATMENT. 21 



FIRE BLIGHT. 



Bacillus amylovorus (Burrill) De Toni. 



This is a very serious disease of the pear. On the apple th 

 disease may start in the blossom or in the tender tips of growing 

 twigs and spread to kill the entire season's growth. Insects 

 are the great agency in the spread of the disease. The trouble is 

 of rare occurrence in New Hampshire, and has been seen by the 

 writer only on trees that were closely adjacent to seriously 



Fig. 25. — Sprayed tree adjacent to the one shown in Fig. 24. 



affected pear trees. The destruction of affected limbs is the 

 only remedy. 



CROWN GALL. 



Pseudomonas tufnefaciens. Erw. Smith and Townsend. 



Crown gall is the term applied to al)normal outgrowths near 

 the surface of the soil in the region of the collar (Fig. 26). It 

 occurs on practically all the stone, pomaceous and bush fruits. 

 With most of these plants the disease has been proven to be 



