90 



Diseases of Economic Plants 



Black-spot ^^^ ^"^ {Pseudomonas pruni EFS.). — Peaches, 

 plums, apricots, nectarines, and more rarely cherries are 



I'lG. 46. — Peach leaves inoculated with culture of Pseudoinottds pruni. 

 Photograph taken 43 days after inoculation. After Eolfs. 



susceptible to black-spot, affecting chiefly the leaves, but 

 occurring, also, on fruit and branch. It constitutes a really 

 serious disease on peaches, being next in importance to 



