FIG. 61. POTATO DISEASES. 



a. Black wart (after Giissow), &. late blight on foliage, c. late blight on tuber, d. 

 successive stages of the development of the conidia of Phyiophthora infestans (b. 

 and d. after L. R. Jones), e. germination of conidia of Phyiophihora infestans, by 

 means of zoopores (after Ward),/, mature oogpnium of P. infestans (after Clinton), 

 /?. melters, surface view, early stage of infection, h. pycnidium of Phoma tuberosa 

 (after Melhus and Rosenbaum). 



