SEEDLING DISEASES AND INJURIES 9 



References on Dampinq-Opf 



Hartley, Carl, and Pierce, R. G. The control of damping-off of conif- 

 erous seedlings. U. S. Dept. Agr. Bui. 453 : 1-32, pis. 1-2, fig. 1. 

 1917. 



Johnson, James. The control of damping-off disease in plant beds. 

 Wisconsin Agr. Exp. Sta. Research Bui. 31:29-61, figs. 1-12. 

 1914. 



Gifford, C. M. The damping off of coniferous seedlings. Vermont 

 Agr. Exp. Sta. Bui. 157 : 143-171, pis. 1^, figs. 1-10. 1911. 



Jones, L. R. The damping off of coniferous seedUngs. Vermont Agr. 

 Exp. Sta. Ann. Rept. 20 : 342-347. 1908. 



Hartley, Carl. Injury by disinfectants to seeds and roots in sandy 

 soUs. U. S. Dept. Agr. Bui. 169 : 1-35, pi. 1, figs. 1-2. 1915. 



Spaulding, Perley. The damping-off of coniferous seedlings. Phyto- 

 pathology 4 : 73-88, pi. 6, figs. 1-2. 1914. 



Hartley, Carl, and Merrill, P. C. PreUminary tests of disinfectants 

 in controlling damping-off in various nursery soils. Phyto- 

 pathology 4 : 89-92. 1914. 



Pettis, C. R. Problems in nursery practice. Proc. Soc.'Amer. Fores- 

 ters 4 : 43-44. 1909. 



Scott, Chas. A. A practical method of preventing the damping-off 

 of coniferous seedUngs. Jour. Forestry 16 : 192-196, pis. 1-2. 

 1917. 



Sun-Scorch 



Caused by over-transpiration and dry soils 



Under the crowded conditions which usually exist in the 

 seed- and transplant-beds, damage from sun-scorch is common 

 and often destructive. Next to damping-ofF, sun-scorch is 

 probably the most important general nursery trouble. A care- 

 ful analysis of the causal conditions and the resulting behavior 

 of the affected plants should make a case of sun-scorch relatively 

 easy of diagnosis. For a discussion of this type of injury in 

 older trees, see page 22. 



Symptoms. 



The entire plants or only the tops may be killed. The area 

 of the beds involved where the entire plants are killed may be 

 more or less circular. Contrary to the action of parasites, how- 



