Fig. 6i. Potato Diseases. 



a. Black wart (after Gussow), b. late blight on foliage, c, late blight on tuber, d. 

 successive stages of the development of the conidia of Phyiophthora infestans (6. 

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

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

 g. melters, surface view, early stage of infection, h. pycnidium of Phoma tuherosa 

 (after Melhus and Rosenbaum). 



