xxii Minnesota Plant Diseases. 



FIG. 176. Black rot of cabbage. Bacteria, highly magnified. After 



H. L. Russell 343 



FIG. 177. Black rot of cabbage. Cabbage heads, apparently sound, are 



attacked by the rot. After H. L. Russell 344 



FIG. 178. Black rot of cabbage. A cabbage leaf showing the manner 



of infection. After H. L. Russell 344 



FIG. 179. Club root of turnips. After Halsted 345 



FIG. 180. Club root of cabbage. After Clinton 346 



FIG. 181. Cedar apples of red cedar. Original 348 



FIG. 182. Rust of apple leaves. After Clinton 349 



FIG. 183. Apple scab on the fruit. After Clinton 351 



FIG. 184. Apple scab on the fruit. After Longyear 351 



FIG. 185. Apple scab on a twig. After Clinton 352 



FIG. 186. Apple scab on the leaf. After Longyear 353 



FIG. 187. Spores of the apple scab fungus. Highly magnified. After 



Longyear 354 



FIG. 188. Blue-mold fruit rot of apple. After L. F. Kinney 355 



FIG. 189. Blue-mold fruit rot of apple. Accessory spores of the fun- 

 gus, highly magnified. After L. F. Kinney 356 



FIG. 190. Bitter rot of apple. After Clinton 357 



FIG. 191. Black knot of wild cherry, showing various stages in the de- 

 velopment of the knots. Original 359 



FIG. 192. Powdery mildew of plums and cherries. Variously magni- 

 fied. After Ellis 3^ 



FIG. 193. Plum Pockets. Photograph by H. Cuzner 362 



FIG. 194. Black rot of apple. After Clinton 364 



FIG. 195. Fire blight of apples. Bacteria which cause the disease. 



Highly magnified. After B. M. Duggar 364 



FIG. 196. Downy mildew of grape. Under surface of an attacked grape 



leaf. Original 368 



FIG. 197. Downy mildew of grape. A healthy and an attacked bunch 



of grapes. Original 369 



