Some Diseases of Beans. 287 



so numerous as to cause heavy loss in the seedHngs and result in a poor 

 stand. Sometimes the stem is so badly diseased or '" eaten " near the 

 base that it falls over and dies. Usually so few of the seedlings are 

 attacked that the presence of the disease in a field is at first overlooked. 

 Nevertheless, as the season advances the fungus spreads to healthy plants 

 near by, by means of its multitude of tiny spores produced in these spots 

 on the seedling, and before the grower knows it his entire field may be 

 badly affected. 



The disease on leaves and stems. — From the spots on stem and seed- 

 leaves of the seedlings the spores find their way to the large leaves and 

 branches of the rapidly growing plants (Fig. loi). The large veins of 

 the leaf are frequently eaten through and killed by the fungus, and 



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Fig. 104..— Beatis badly affected with anthracnose. Such seed should never be planted. 



holes or cracks with blackened margins appear in the blade. While this 

 may not entirely kill the leaf, it greatly lessens its efficiency as a starch 

 maker and so indirectly but effectively reduces the yield of seed. Many 

 times, however, the attack is so severe that the leaf stems are cut off 

 and the entire plant is practically ruined (Fig. 102). 



The disease on pods. — It is from the attack of the disease on the 

 pods that the most direct and apparent damage to the crop results. 

 During the time of blossoming and previous, the fungus has been spread- 

 ing and becoming established on the stems and leaves, and it now attacks 

 the young and succulent pods. With their tender growing tissue full of 

 water and food materials, these pods offer the best of conditions for the 



