PLATE 2 
A. —a, Upper surface of a spinach leaf affected with downy-mildew (cause: Peronos- 
pora effusa ), showing the light areas which might be mistaken for early symptoms 
of spinach-blight. b t The under surface of a similar leaf. Note the growth of the 
fungus about the tip. (Original.) 
B. —Spinach leaves affected with Heterosporium leafspot. This disease, besides 
appearing as definite black spots, may cause the leaves to become more or less yellowed, 
similar in appearance to blighted leaves. (Original.) 
