54 



BEAN CULTURE 



not carried to healthy beans from diseased plants 

 by insects or some other means. The fungus con- 

 sists entirely of tiny colorless threads in the tissue 

 of the bean and the spores produced at the surface 

 of the black spots. After a heavy rain or dew these 

 spores may easily become attached to insects which 

 visit the diseased plants and so be ca'rried to healthy 

 ones. 



Hoeing -the beans when they are wet is also sure 

 to scatter the spores in flying drops of water. While 



FIG. 17 BEAN LEAF BEETLE. (fl) , ADULT BEETLE J 



(b), PUPA; (c), LARVA; (/), EGGS. 



the weather is not directly responsible for the dis- 

 ease itself, it has very much to do with the preva- 

 lence and destructiveness of anthracnose. When 

 there is an abundance of moisture, the spore masses 

 quickly dissolve and the spores are easily distrib- 

 uted by insects, rabbits, or other animals running 



