SYLVICULTURAL NOTES ON NORWAY SPRUCE. 295 



The Spruce has many insect foes, and recovers less 

 readily from injury than the Scotch Pine. The seed- 

 lings and young plants suffer like those of the Scotch 

 Pine, Ilylolius abietis being a great danger (page 301). 

 Many Tortrices live on the twigs and needles ; the 

 chief devourer, however, is tl^e nun, Liparis monacha, 

 which has caused widespread destruction. The Spruce- 

 gall Aphis, Chermes abietis,* cripples the shoots. The 

 bark-beetles, Tomicus typographies and its allies, are the 

 most destructive insects. They especially follow cater- 

 pillar-attacks, and are perhaps more dreaded than any 

 other forest-insects of Europe. 



Spruce is also much infested by fungi. Young seed- 

 lings are attacked by Phytophthora omnivora, which kills 

 large patches of them in nurseries. Young plants up 

 to a few years old become yellow and succumb, owing to 

 Pestalozzia Hartigii. Trametes radiciperda and Agaricus 

 melleus attack the roots. Red-rot is produced in 

 the root and the stem by Polyporus vaporarius ; white- 

 rot by Polyporus fulvus and borealis, Trametes radiciperda 

 and pini ; green-rot by Peziza ceruginosa. There are 

 many other species of minor importance. 



Young Spruce woods require watching, lest Birch, 

 Aspen, and Willow should settle in them and injure 

 the Spruce. 



Pruning. Spruce does not stand the pruning of 

 green branches, the operation being generally followed 

 by a falling off in height-growth. Opinions differ 

 regarding the expediency of pruning off dry branches ; 



* There is some reason to believe that this is identical with Chermes laricis, 

 the insect breeding alternately on Spruce and Larch. 



