282 Studies in Forestry [CHAP. xin. 



General Classifications of the Chief Fungoid Diseases 

 of Sylvicultural Importance. 



I. ON FOLIAGE. 



A. Of Conifers: 



1. Hysterium pinastri^ Pine scab or scurf. Mainly attacking 

 Scots Pine. 



2. Chrysomyxa abietis, Spruce needle-rust or blight. Mainly 

 attacking Spruce. 



3. Aeddium pint, var. aricola, Pine needle-rust or blight. 

 Mainly attacking Pines. 



4. Trichosphaeriaparasitica, Silver Fir needle-blight. Mainly 

 attacking Silver Fir and Spruce. 



Minor disorders are occasioned by Hysterium nervisequium 

 on Silver Fir, H. macrosporum on Spruce, Caeoma laricis on 

 Larch, C. abietis pectinatae on Silver Fir, Aeddium columnare on 

 Silver Fir, A. abietinum on Spruce, and A. strobilinum on the 

 bracts of Spruce cones. 



B. Of Broad-leaved Trees : 



i. Phytophthora omnivora, Beech-seedling fungus. Mainly 

 attacking Beech, Maples, Ash ; Spruce and Scots Pine (in 

 nurseries and young seedling growth). 



Minor disorders are due to Melampsora Hartigii on Willows 

 (especially S. caspicd) ; M. tremulae on Aspen, M. Betulina 

 on Birch, and M. salidna on Sallow, also Rhytisma acerinum 

 on Maples and Sycamores \ 



1 It may here be remarked that there is reason to believe that Caeoma 

 laricis and C. pinitorquum can both of them pass through their aecidial 

 stage either as Melampsora tremulae on Aspen or as M. Betulina on Birch ; 

 and that the spores of either of these latter forms may infect the shoots of 

 Scots Pine with Caeoma pinitorquum or the foliage of Larch with C. laricis. 

 Hence Birch and Aspen should be treated as weeds and cut out, wherever 

 either of these diseases is prevalent among Pine or Larch woods. 



