BULLETIN OF THE 



No. 169 



Contribution from the Bureau of Plant Industry, Wm. A. Taylor, Chief. 

 February 20, 1915. 



PROFESSIONAL PAPER. 



INJURY BY DISINFECTANTS TO SEEDS AND ROOTS IN SANDY 



SOILS. 



By Carl Hartley, Pathologist, Investigations in Forest Pathology. 

 INTRODUCTION. 



For several seasons the writer has conducted experiments in the 

 application of disinfectants to pine seed beds for the purpose of con- 

 trolling damping-off. Formaldehyde and various inorganic acids 

 and salts have been tested. The work conducted at two of the 

 nurseries with seed beds sown in the spring and summer has now 

 been completed. The practical results of the disease-control work 

 have already been briefly summarized. 1 Because of the interest of 

 soil investigators as well as plant pathologists in the behavior of dis- 

 infecting agents in the soil, the data on injury to pine and weed 

 seedlings by disinfectants are here published separately. Data on 

 the effects of the disinfectants on the growth rate of pine seedlings 

 are still being gathered from three nurseries, and it is hoped to pub- 

 lish these later. 



Acknowledgments are due Dr. F. K. Cameron and others, of the 

 Bureau of Soils, and Drs. Rodney H. True and F. D. Heald, of the 

 Bureau of Plant Industry, for helpful suggestions. 



SOIL CHARACTERS. 



The nursery where most of the work was done is at Halsey, Nebr., 

 in a valley among sand hills. The soil throughout the nursery area 

 is quite uniform, both soil and subsoil being classed as fine sand. 

 There is a fair amount of humus in the upper 10 to 12 inches, in some 

 places extending to nearly 20 inches below the surface. Below 12 

 inches there is no humus in most of the nursery. The soil at the 

 other nursery, that of the Pennsylvania Railroad, near Morrisville, 

 Pa., is a light-gray sandy loam, with a fine, reddish, sandy subsoil 

 which is rather nearer the surface than the subsoil at Halsey. Exami- 



1 Hartley, Carl, and Merrill, T. C. Preliminary tests of disinfectants in controlling damping-off in vari- 

 ous nursery soils. In Phytopathology, v. 4, no. 2, p. 89-92, 1914. 

 71222°— Bull. 169—15 1 



