FUNGI AFFECTING THE SPINACH 



The Spinach Mildew 



Peronospora effusa 



Spinach, wlien forced for market under glass, is 

 subject to attack bv several fungous diseases, wliicli have 



been investigated by Dr. B. D. 

 llalsted. The mildew is one of 

 the most destructive of these mal- 

 lidics. It is closely related to the 

 downy mildew of the potato, and 

 produces *'gray, slightly violet, 

 patches (i a velvety texture, upon 

 the under side of the leaves, while 

 from the upper side they liave a 

 pale yellow shade, due to the loss 

 of the green color.*' If a cross 

 section of the leaf be made through 

 one of these patches, and ii minute 

 jiiece placed under the microscope 

 on a glass slide, the fungus Vv-ill 

 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- 

 2:us runnins: between some of 

 them, sending here and there 

 ''suckers" into the cells them- 

 selves to absorb their contents, 

 and pushing out through the 



FIG 75. SPIJfACH IMIXBEW. , ,, . ^ ^ « +"Uo -Pvnifi'nrr 



Section of leaf showiui^nivceii- brcathmg porc, tt, the truiting 



Mag'JifieJr''"'''''"'''''^ ''"''"• stalk, i, which bears the spores, c. 



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



spores are scattered to other plaiits, where they germinate 



