BUREAU OF PLANT INDUSTRY. 395 



Department of Agriculture. The station will be equipped with suit- 

 able buildings for carrying on general experimental work, including 

 the testing and propagation of trees, shrubs, fruits, and vegetables 

 for the Great Plains area. 



Potato and sugar beet station. — Among the miscellaneous appro- 

 priations for the department for the fiscal jear 1913 was a paragraph 

 appropriating $10,000 for the investigation of the cultivation, accli- 

 mating, and development of improved types of potatoes and sugar 

 beets. Under the authority contained in this section, a potato and 

 sugar beet station has been started just outside of the city of Jerome, 

 Idaho, where experiments with potatoes and sugar beets have been 

 commenced and will be activel}' pushed with the opening of the next 

 growing season. The main object of the work is to develop types 

 particularly adapted for culture under irrigation. 



PLANT-QUARANTINE ACT. 



Under the plant-quarantine act approved August 20, 1912, what 

 is known as the Federal Horticultural Board has been organized, 

 with two representatives of the bureau thereon. The necessary regu- 

 lations for the enforcement of the act have been promulgated, and 

 under them the importation of potatoes from countries infected with 

 the potato wart has been prohibited ; also the importation of four 

 species of pine, in order to protect the pine forests of this country 

 against the white-pine blister rust. 



SUMMARY OF PROGRESS. 



Brief summaries of the progress of the work in the various 

 branches of the bureau are set forth in the accompanying pages. 



LABORATORY OF PLANT PATHOLOGY. 



The work of the Laboratory of Plant Pathology has continued 

 under the charge of Dr. Erwin F. Smith, assisted by Dr. R. E. B. 

 McKenney, Miss Nellie A. Brown, Miss Florence Hedges, and others. 



Knot of citrus trees. — A bulletin on the knot of citrus trees caused 

 by Sphaeropsis tumefaciens has been completed and published. The 

 investigations reported therein cover a period of six years, during 

 which time the cause of the disease has been established beyond doubt 

 by means of numerous inoculations, reisolations of the fungus from 

 the knots thus artificallj'^ produced, and reinoculations with the 

 fungus thus obtained. This disease has proved destructive in 

 Jamaica, and recently the same or a very similar malady has been 

 discovered in Florida. It occurs also on oranges in Cuba. The dis- 

 ease is characterized by the formation of abnormal growths whicli 

 cause the branch or stem beyond them to become stunted and finally 

 die. Under favorable conditions witches'-brooms and many sec- 

 ondary knots are formed. Experiments have shown that the disease 

 can be controlled by cutting and burning the diseased parts. In 

 pruning, the fact must be borne in mind that the fungus may extend 

 tai* beyond any external sign of infection. 



