20 MANUAL OF TREE DISEASES 



due to winter-drying or to fungous attack is to note carefully 

 the needles affected on a few trees and then watch the trees 

 throughout the season. If no further spread of the trouble is 

 apparent during the summer, one may usually be assured that 

 the damage was due to temperature conditions and not to 

 leaf -parasites. 



Control. 



Little can be done to protect trees from winter-drying. In 

 the case of ornamental conifers, it should be remembered 

 that this trouble is cotnmon in places exposed to the wind 

 and that young trees with shallow root systems are most 

 susceptible. Mulching the soil around small trees may be 

 advisable during winters when there is little snow on the 

 ground. 



Refebbncbs 



stone, G. E. Winter-injuries, drouglit, sun-seoreli, and bronzing of 



leaves. In Shade trees, characteristics, adaptation, diseases 



and care. Massachusetts Agr. Exp. Sta. Bui. 170 : 199-212. 



1916. 

 Morse, W. J. Winter injury of the white pine in 1908. In Notes 



on plant diseases in 1908. Maine Agr. Exp. Sta. Bui. 164 : 21- 



28, fig. 4. 1909. 

 Hedgcock, G. G. Notes on some diseases of trees in our national 



forests. III. Phytopathology 3: 111-114. 1913. 

 Spaulding, Perley. The present status of the white-pine blights. 



U. 8. Dept. Agr. Bur. PI. Ind. Circ. 35 : 1-12. 1909. 

 Brooks, Charles. Pine blight. In Report of the Department of 



Botany. New Hampshire Agr. Exp. Sta. Ann. Rept. 19-20 : 



370-371. 1908. 

 Hartley, Carl P. Notes on winterkilling of forest trees. Forest 



Club (Univ. Nebraska) Ann. 4 : 39-50. 1912. 

 Galloway, B. T., and Woods, A. F. Desiccation, or drying out, and 



low temperatures. In Diseases of shade and ornamental trees. 



U. S. Dept. Agr. Yearbook 1896 : 243-246. 1897. 

 Metcalf, Haven. Drying out. Effects of cold. In Diseases of 



ornamental trees. U. S. Dept. Agr. Yearbook 1907 : 486-487. 



1908. 



