290 



Bulletin 239. 



usually be detected by the brown or yellowish discoloration of the seed- 

 coat. When the seeds are badly affected, they become more or less 

 shriveled as well as discolored (Fig. 104). It is thus easy to tell with con- 

 siderable certainty whether seed to be planted is affected with anthracnose. 

 When the seed is planted in the spring the enclosed but dormant fungus 

 is planted with it. The moisture and warmth which stirs the bean to 

 life awakens the fungus also. In the soft and fleshy seed-leaves in which 

 it is imbedded the mycelium finds an abundance of food and grows rap- 

 idly, soon forming a spot or canker and producing spores which at once 

 begin again to spread the disease to neighboring healthy plants. 



Fig. 107. — Above, unsprayed; below, sprayed once with Bordeaux mixture. The 

 spotted pods are placed at the Icjt in each case. 



Treatment of Anthracnose 



Seed treatment. — Soaking the seed in formalin, corrosive sublimate 

 and other poisons, and in hot water, have been tried by different experi- 

 menters with varying results. So far no one has been able to prevent the 



