ORGANIZATION OF THE UNITED STATES DEPARTMENT OF 

 AGRICULTURE. 



Secretary of Agriculture Henry C. Wallace. 



Assistant Secretary C. W. Ptjgsley. 



Director of Scientific Work E. D. Ball. 



Director of Regulatory Work 



Weather Bureau Charles F. Marvin, Chief. 



Bureau of Agricultural Economics __. Henry C. Taylor, Chief. 



Bureau of Animal Industry John R. Mohler, Chief. 



Bureau of Plant Industry William A. Taylor, Chief. 



Forest Service W. B. Greeley, Chief. 



Bureau of Chemistry Walter G. Campbell, Acting 



Chief. 



Bureau of Soils Milton Whitney, Chief. 



Bureau of Entomology L. O. Howard, Chief. 



Bureau of Biological Survey E. W. Nelson, Chief. 



Bureau of Public Roads Thomas H. MacDonald, Chief. 



Fixed-Nitrogen Research Laboratory F. G. Cottrell, Director. 



Division of Accounts and Disbursements A. Zappone, Chief. 



Division of Publications John L. Cobbs, Jr., Chief. 



Library Clarlbel R. Barnett, Librarian.. 



States Relations Service A. C. True, Director. 



Federal Horticultural Board C. L. Marlatt, Chairman. 



Insecticide and Fungicide Board J. K. Haywood, Chairman. 



Packers and Stockyards Administration \ Chester Morrill, Assistant 



Grain Future Trading Act Administration / to the Secretary. 



Office of the Solicitor R. W. Williams, Solicitor. 



This bulletin is a contribution from the — 



Bureau of Plant Industry William A. Taylor, Chief. 



Investigations in Forest Pathology Haven Metcalf, Pathologist in 



Charge. 

 16 



ADDITIONAL copies 



OF THIS PUBLICATION MAY BE PROCURED FROM 



THE SUPERINTENDENT OF DOCUMENTS 



GOVERNMENT PRINTING OFFICE 



WASHINGTON, D. C. 



AT 



10 CENTS PER COPY 



PURCHASER AGREES NOT TO RESELL OR DISTRIBUTE THIS 

 COPY FOR PROFIT.— PUB. RES. 57, APPROVED MAY 11, 1922 



