98 MASSACHUSETTS HORTICULTURAL SOCIETY 



and judging from results to date it would seem that control will 

 resolve itself into some method of soil treatment, probably soil 

 sterilization. The fungus grows well on both acid and alkalin 

 media so that the possibility of control by developing an acid or 

 alkalin condition of the soil does not appear to be promising. Soil 

 sterilization and the exercise of care in using only healthy stock and 

 scions for grafting may be the only feasible method of controlling 

 the disease. Investigations of control measures are being con- 

 ducted in cooperation with Professors A. V. Osmun and P. J. 

 Anderson of the Massachusetts Agricultural Experiment Station. 

 Progress to date has been encouraging and it is hoped that some- 

 thing definite can be offered growers in the near future. 



Crown-Gall. 



This is a very common disease of the rose, both of plants grown 

 under glass and out-of-doors. It is the common crown-gall disease 

 of the nursery, affecting many woody plants, trees, and shrubs, as 

 well as herbaceous plants. Roses in benches are frequently severely 

 affected. Much interest in recent years has been attached to the 

 study of this disease because of its resemblance to malignant 

 human tumors, with the possibility that light may be thrown upon 

 the latter. 



History and distribution. The disease has been known in Europe 

 for over fifty years, being generally ascribed to frosts and mechani- 

 cal injuries by many workers. According to Smith, Townsend 

 and Brown (14), Scalia described a tumor occurring an old stems 

 of the rose near the surface of the earth, but also frequently higher 

 up. It is impossible to be quite certain that the disease described 

 by Scalia is identical with the crown-gall of the rose as it occurs in 

 this country. 



In the United States references to the disease in literature begin 

 about the year 1892, but undoubtedly the disease has been present 

 for a long time. It has been reported as occurring in all the states. 



Economic importance. Opinions differ as to just how much 

 damage this disease causes to roses. Skilled gardeners are gener- 

 ally of the opinion that serious injury is done, diseased plants being 



