200 



DISEASES OF ECONOMIC PLANTS 



Since the spores arc spread only when they are wet, 

 handling or disturbing the vines in any way while the 



Fig. 89. — Boan rust upon leaf and pods ; note the numerous sori upon both surfaces. 

 After Heach. 



dew or rain is still upon them should be avoided. Seeds 

 already bearing the fungus, i.e., spotted seeds, should 

 never be planted, since they not only raise sick plants, 



