66 PROTECTION OF PLANTS, 1921-22 



the remainder vertical, some of the cortical surface dries up and falls leaving 

 bare the adjacent ligneous layers. Nevertheless the tree may continue to live. 



The Bronze Birch Borer {Agrilus anxius Gor3^) 



This borer belonging to the Buprestidse family of the Coleoptera is a 

 scourge but recently established in Quebec. During the past seven years, numer- 

 ous cat leaf birches, very handsome trees, have been killed by this insect. 

 Unlike the sugar maple borer, the larvse of this pest appear in large numbers on a 

 single tree, and their numerous burrows completely cover the trunk with a 

 labyrinth of tunnels. The smaU pale larva lives but one year and the following 

 •spring the adult leaves the tree by an elliptical opening. This adult is a small 

 bronze black, cylindrical insect. It is safe to say that a birch when once in- 

 fested with this borer is bound to die within two or three years. 



The Poplar Borer {Saperda calcarata Say). 



Although less decorative than the birch, the species of the Populus are 

 widely planted here as ornamental trees. They are unfortunately the victim of 

 many diseases of fungous and insect pests of which the Saperda is one of the most 

 important. The larva is thick and fat and bores its tunnels vertically right in 

 the sap wood. These are like gimlet holes and are filled with coarsely torn 

 fibres and woody particles with which the larva surrounds itself at the time of 

 metamorphosis. Since it grows for three years constantly increasing in size, 

 the burrow becomes very wide and causes serious derangement in the life and 

 growth of the tree. The adult is a beautiful insect covered with a greyish down, 

 sometimes colored with brown or yellow. The insect belongs to the Cerambycidse 

 family of the Coleoptera. 



Poplar and WiUoiv Borer. (Cryptorhynchus lapathi). 



This insect was practically unknown here ten years ago but is found now in 

 several places. As to its origin there seems to be no doubt that this wood borer 

 was introduced from Ontario and is still coming in with plants imported from 

 that province. It attacks with preference Carolina Poplars which succumb to 

 its depredation a year after they are planted. The larvae bore into the young 

 trunk in several places and kill the outside portion, but fortunately the poplar 

 rebuilds new tissue from the base of the trunk. 



The larva is pale and fleshy. The adult has a rather small body, black 

 in color, with the extremities of the wings greyish and sometimes pink. 



Conclusion 



We can only preserve our ornamental trees intact by exercising the neces- 

 sary precautions. Essential measures consist in keeping the trees tidy, the 

 removing of the diseased portions and the cleaning of the bark. In case of an 

 epidemic of caterpillars the tree may be preserved by the timely application of 

 arsenical solutions. Wood borers may be easily exterminated with carbon 

 bisulphide. Finally, in the spring and fall, eggs, cocoons, etc. should be collected 



