EXrERIMENT STATION BULLETINS. 



269 



SOME BACTERIAL DISEASES OF PLANTS PREVALENT IN MICHIGAN. 



WALTEB G. SACKETT. 



-^ [Bulletin No. 230.] 



I. Pear Blight. 



II. Bacteriosis of Beans. 



III. Black Rot of Cabbage. 



IV. Wilt of the Cucumber, Muskmellon and Squash. 

 V. Soft Rot of the Sugar beet. 



VI. Blight of the Irish Potato, Tomato and Egg Plant. 



PEAR BLIGHT (Fire Blight). 



Fig. 1. — Two Pear Twigs; the upper one affected with Fire Blight, the lower one healthy. 



Of all the diseases which affect the pear, there is none which is so universally- 

 dreaded by fruit growers as the pear blight. This disease is by no means confined 

 to the pear alone but also infests the apple, quince, crab, mountain ash, service 

 berry and several species of hawthorne; hence the blight can spread from one 

 kind of a tree to another. 



The name fire blight is especially good because it is at once suggestive of the 

 symptoms of the malady. To one not familiar with the disease, it can be recog- 

 nized at first sight by the brown and subsequent blackened appearance of the 

 young leaf tufts and flower clusters; the young twigs show a blackened, shrivelled 

 bark resembling very much green brush which has been only partially burned. 



