FUNGI AFFECTING THE SPINACH 



The Spinach Mildew 



Peronospora effusa 



Spinach, when forced for market undi-r glass, is 

 subject to attack by several fungous diseases, which have 

 been investigated by Dr. B. D. 

 Halsted. The mildew is one of 

 the most destructive of these mal- 

 adies. It is closely related to the 

 downy mildew of the potato, and 

 produces "gray, slightly violet, 

 patches of a velvety texture, upon 

 the under side of the leaves, while 

 from the upper side they hav 

 pale yellow shade, due to the 

 of the green color." If a cross 

 section of the leaf be made through 

 one of these patches, and n minute 

 piece placed under the microscope 

 on a glass slide, the fungus will 

 be seen to have a structure similar 

 to Fig. 75, which represents on 

 the lower part the cells of the leaf 

 having the mycelium of. the fun- 

 gus running between some of 

 them, sending here and there 

 "suckers" into the cells them- 

 selves to absorb their contents, 

 and pushing out through the 

 breathing pore, a, the fruiting 

 M3fiea evelopmenl >fspore ' stalk, b, which bears the spores, c. 

 At d one of the spores is shown, more magnified. These 

 spores are scattered to other plants, where they germinate 



