FIELD DISEASES 145 



and it is to be found wherever clovers are 

 grown. 



Symptoms. Like the bacteriosis of the 

 bean, streak makes its appearance in the 

 season of heavy dew. On the sweet pea 

 the disease usually appears just as the 

 plants begin to bloom; it is manifested by 

 light reddish brown to dark brown spots 

 and streaks (the older almost purple) 

 along the stems, having their origin usu- 

 ally near the ground, which indicates dis- 

 tribution by spattering rain and infection 

 through the stomata or through insect in- 

 jury. The disease becomes distributed 

 quickly over the mature stems until the 

 cambium and deeper tissues are destroyed 

 in continuous areas, and the plant dies 

 prematurely. From the stem the disease 

 spreads to the petioles, flowers, peduncles, 

 and pods, the symptoms in these cases be- 

 ing similar to those on the stems. On the 



