Insect Attack. 33 



This may be cured, but It is better to 

 prevent it by inducing growth by culture and 

 care. The cure may be effected by drainage 

 when the soil is wet, by cutting through the 

 outer bark longitudinally with a sharp knife, 

 by keeping the bark moist by compost or 

 hay bands kept wet, and by scraping off 

 the outer bark. 



INSECT ATTACK. 



Another cause is that of insect attack, 



which often, indirectly perhaps, renders the 



bark inactive, but this will be considered 



under the head of insects which injure forest 



trees. Among these are the ash bark beetle 



{Hylesinus fraxini), ash bark scale [Chion- 



aspis fraxini), elm bark beetle (Scolytus 



destructor), goat moth {Cossus Itgniperdd), 



buff tip moth {Pygera bucephala), cockchafer 



{Melolontha vulgaris), marble gall fly {Cynips 



Kollari), oak leaf roller moth {Tortrix 



viridana), pine beetle {Hylurgus piniperda), 



pine saw fly {Lophyrus pini), pine weevil 



{Hylobius abietis), spruce gall aphis {Chermes 



abietis). These insect pests attack the trees 



D 



