DEPARTMENT OF BACTERIOLOGY 127 



DEPARTMENT OF BACTERIOLOGY 



The work of this department during 1901 was directed to the 

 study and treatment of fungous diseases of plants, storage of apples, 

 bacteriology of ensilage, and the study of weeds. 



NOTES ON FUNGOUS DISEASES 



The season of 1901 seemed to be very favorable to the develop- 

 ment of these diseases. Most of the familiar ones — such as apple 

 leaf and fruit spots, pear scab, black knot, tomato rot, early and 

 late blight of potatoes — were present in at least their average 

 abundance. Several seemed to be more abundant than usual. Of 

 these the following have not been specially considered in previous 

 bulletins of this Station : 



Peach Leaf CurL — This is a disease which attacks the leaves, 

 twigs, flowers, and fruit of the peach. It takes its name from the 

 ciiaracteristic appearance of the affected leaves. These become 

 strongly wrinkled or puckered, owing to the unusual development 

 of the cells of certain areas caused by the presence of the vege- 

 tative part of a fungus. Later the wrinkled surface takes on a 

 whitish or frosted appearance, due to the development of the 

 fruiting or spore-bearing part of the fungus. The leaves turn 

 yellow and soon drop off. Diseased twigs become swollen and 

 distorted ; diseased fruits drop off. The losses caused by this 

 disease are oftentimes very serious ; but it ajjpears that they may 

 be largely prevented by suitable treatment. According to a re- 

 cent bulletin of the Division of Vegetable Pathology of the Uni- 

 ted States Department of Agriculture, the chief source of infec- 

 tion in case of this disease is the spores which germinate in the 

 spring and attack the first tender growth from the opening buds. 

 The treatment recommended and which has proved very success- 

 ful, is a thorougli spraying of the trees with Bordeaux mixture a 

 sliort time previous (two weeks) to the opening of the buds. 



Plum Rot. — This disease attacks the fruit at, or a short time 

 previous to, the period of ripening. Its first appearance is as a 

 brown spot, which rapidly spreads until the whole ])lum is in- 

 volved. Upon the])rown surface there soon appears an abundant 



