Department of Plant Pathology Ixxxv 



Crown gall. — A number of the peach and apple trees that were set in 

 the disease garden in order to determine the effect on them, under Xew 

 York conditions, of the crown-gall disease, were injured by the severe 

 winter and by ice. Fortunately, nearly all survived and developed a 

 strong renewal from near the ground. It is not possible at the present 

 time to distinguish the healthy from the galled trees. 



Investigation of the fungicidal value of sulfate of iron. — The experi- 

 ments on the control of raspberry anthracnose were continued as for last 

 year, but the results were not nearly so satisfactory for any of the 

 fungicides tried. 



The work started last year on diseases of the peach and the apple was 

 continued, but the scarcity of fungous diseases made most of the work 

 unsatisfactory. It has been demonstrated by extensive experimicnts that 

 sulfate of iron has no value for the control of the leaf-curl disease of 

 peaches. David Gunn, a special student in Entomolog}', established the 

 fact in connection with this work that iron sulfate has no value as a 

 destroyer of San Jose scale. This was an important point because a 

 fungicide having no value as a scale destroyer would be practically worth- 

 less as a dormant spray for peaches. 



Investigation of peach black-canker. — This work was supported by 

 peach-growers in the town of Xew fane, Niagara count)-. R. A. Jehle 

 has brought parts of the investigations to a satisfactory' conclusion, but 

 unfortunately he will not have an opportunity to continue control experi- 

 ments that give promise of 3^ielding successful results. The cause of the 

 canker has been determined to be Sclerotinia fructigena, and this has 

 been proved by repeated inoculations and isolations. Blossom blight 

 seems to play an important role in the production of cankers, and the 

 control of blossom blight has been one of the points receiving special 

 attention. Frost cankers have been studied in this connection. The 

 fungus Valsa leucostoma, frequently associated with frost cankers, has 

 given only negative results when inoculated into healthy trees. 



Peony disease investigations. — This work has been taken up in connec- 

 tion with the pathological work of the Society of American Florists. 

 The botn,-tis blight has received some attention during the past year and a 

 popular treatise, "A Destructive Disease of Peonies," has been published 

 (Florists* Exchange 1912: 565-566. figs. 1-4). 



The violet disease. — An investigation of the root rot, or black-rot, of 

 violets has been made possible by the financial cooperation of the 

 Rhinebeck A'iolet Growers ]\Iutual Protective Association. The cause of 

 the disease has been determined and experiments looking toward its 

 control are now under wav. 



