PLATE VII 
Phytophthora infestans: Infection of potato plants 
Fig. i.—A hill of potatoes having 13 shoots grown from a whole infected tuber in 
the field. The smallest shoot, indicated by the arrow, became infected by the myce¬ 
lium growing up through the stem from the parent tuber. 
Fig. 2.—In this hill with two shoots the fungus has reached the surface and killed 
its host. 
Fig. 3.—This shows the hill illustrated in Plate VII, fig. 2, in its position in the row 
where it grew. Notice the poor stand obtained by planting infected seed potatoes. 
This hill did not become a center for the spread of P. infestans , owing to its isolation 
in the row and early occurrence. 
5771°—15 - i 
