24 ANNUAL EEPOETS OF DEPARTMENT OF AGRICULTURE. 



turers would be relieved of the expense of conducting their own tests. 

 While the plan indicated contemplates control only of serum intended 

 for shipment in interstate commerce, it is likely that the States 

 would take similar action and apply similar rules to their own plants 

 as well as to private establishments doing business wholly within the 

 State. The plan probably would be effective and would require little 

 additional expenditure of public funds. 



CITRUS CANKER. 



The citrus industry of the Gulf States is seriously threatened by 

 citrus canker. This has been found to be a highly infectious bac- 

 terial disease. An emergency appropriation of $35,000, which became 

 available January 28, 1915, enabled the department to cooperate with 

 the States of Florida, Alabama, Mississippi, Louisiana, and Texas 

 in an effort to eradicate the trouble, the department bearing the cost 

 of the inspection work, while the expense incident to the actual de- 

 struction of trees was borne by the respective States. The work of 

 inspection and eradication has progressed very satisfactorily, although 

 the disease is more widely scattered and is more serious than at first 

 was supposed. In Texas, Mississippi, and Alabama the greater num- 

 ber of the infected centers have been eliminated, and, if it is possible 

 for these States to maintain a thorough inspection during the com- 

 ing year, there appears to be no reason why the disease should not 

 be completely eradicated from these regions. In Louisiana and 

 Florida the greater portion of the infected areas seems to be under 

 control, but the complete elimination of the disease, especially from 

 the latter State, probably will require large expenditures for at least 

 two years. 



POTASH SUPPLY. 



The potash situation continues very serious and a grave condition 

 confronts the American farmer. There is practically no potash in 

 this country for fertilizer use, and present indications are that the 

 supply for this purpose will not be increased materially during the 

 coming year. The investigations of the department and of the 

 Geological Survey have shown the possibility of producing from 

 American sources an ample quantity of potassium salts for domestic 

 consumption. During the year no new sources have been dis- 

 covered, but the conditions surrounding the development of laiown 

 sources have been clarified considerably. There are four possible 



