EEPORT OF THE SECRETARY OF AGRICULTURE. 27 



many of the best groves at least 10 per cent of the trees of the stand- 

 ard varieties are of inferior strains, which should be eliminated by 

 top- working. The growers who have observed the experimental plots 

 realize the importance of this work and already have undertaken the 

 conversion of the undesirable trees by top-working on a rather large 

 scale. This study will be extended to some of the deciduous-tree 

 fruits. 



As the economic soundness of commercial fruit orcharding to a 

 considerable extent rests upon the maintenance of high average 

 annual production, it is obvious that the results of this investigation 

 are of fundamental importance to the fruit industry. 



STJGAB-BEET INDUSTRY. 



The production of beet sugar in the United States has increased 

 during the past four years from less than 700,000 tons to approxi- 

 mately 900,000 tons. During the past year seven new localities for 

 sugar-beet production have been developed. But for the existing 

 shortage of sugar-beet seed a considerably larger increase of produc- 

 tion would have been secured. 



Stimulated by the inadequate supply of seed from European 

 countries American growers now are undertaking seriously the pro- 

 duction of seed. Approximately 4,000 acres, which should produce 

 about one-fourth of the present requirements, have been devoted to 

 this purpose during the current year. A special appropriation made 

 at the last session of Congress will enable the department to cooper- 

 ate with the industry in solving some of the more technical problems 

 involved. It is hoped that, as a result of this work, the industry 

 may be freed from the menace of seed shortage which during the 

 past two years seriously threatened its existence. 



CONTROL OF PLANT DISEASES. 



It is very clear that fuller knowledge of the distribution and the 

 nature and methods of control of crop diseases is essential. In 

 some seasons, when unusual climatic conditions prevail at critical 

 periods, diseases greatly lessen or practically destroy particular 

 crops throughout important producing districts. Progress has 

 been made in determining their exact character and in develop- 

 ing methods of control, but the destructiveness of certain diseases 

 under climatic conditions favorable to their spread necessitates 

 72412°— agr 1916 3 



