30 



FUNGI AND FUNGICIDES 



Literature. Articles concerning apple scab may 

 be found in the following publications : Bulletin Ohio 

 Experiment Station, IV, No. ; Report IT. S. Dept. 

 Agriculture, 1887, pp. 341-347 ; First Report Wisconsin 

 Experiment Station, 1884, pp. 45-56; Cornell Univer- 

 sity Experiment Station, Bulletin 48. 



The Powdery Mildew 



Podosphcera oxyacanthce 



About midsummer one may often find on the leaves 

 and young shoots of apple, cherry, quince, peach, and 



FIG. 14. SECTION SHOWING SCAB FUNGUS. 



A, spores in position, as developed; B, skin of fruit turned tip; C 1 , parenchyma- 

 like cells of the parasite ; D I), tissues of the fruit. Much magnified. 



several other trees, small round whitish blotches of mil- 

 dew, which at first have more or less of a radiated ap- 

 pearance, due to the spreading of the threads. In a 

 short time many of the spots enlarge so that they run 



