66 BACTERIAL DISEASES OF PLANTS 



Potter has written on a rot of swedes and Paine on a rot of 

 mushrooms and a leaf-spot of Protea. 



France and Italy. Potato diseases are common and at times 

 very destructive. Olive tubercle, common also in California, 

 and all around the Mediterranean, is prevalent in spots. Vine 

 diseases, especially Maladie d'Oleran and crown gall, do con- 

 siderable damage. Pear blight seems to be absent in France, 

 but has been reported from several places in Italy. Mul- 

 berry blight occurs. The destructive Italian rice disease, 



FIG. 48. Bacterial citrus canker enlarged and photographed by transmitted light 

 to show translucent border. X 6. The tiny white specks are oil glands. 



brusone, is not due to bacteria as reported, but to a fungus 

 (Piricularid) . Not much exact work has been done on bacterial 

 diseases of plants either in France or Italy. 



Spain and Portugal. These countries are a terra incognita. 



Russia. A few years previous to the late war there was a 

 great awakening in Russia. A plant pathological journal w r as 

 founded and numerous discoveries were reported. From this j our- 

 nal and other sources it is evident that many bacterial diseases 

 of plants occur. I think, for example, that our black chaff of 

 wheat is an importation from Russia. At least it should be 



