INSECTS INJURIOUS TO FOREST TREES 513 



in the burrows may be killed by injecting a little carbon 

 bisulphide into the hole after the castings and exudations have 

 been cleared from the entrance. The hole in the bark should 

 then be filled with cement. 



The Leopard-moth (Zeuzera pyrina). The leopard-moths are 

 beautiful white moths that have their bodies and wings marked 

 with many black spots. The larvae may 

 be found in any part of the tree, but they 

 more often attack the smaller limbs. As 

 they work principally in the sapwood, 

 the affected limbs are usually killed. The 

 only satisfactory method of treatment is 

 to cut out all the infested wood and burn 

 it. It is easier and safer to sacrifice the 

 whole tree if it is badly infested. The 

 female moths do not fly readily, so the 

 infestation does not spread rapidly except 

 in places where the trees are very close 

 together. 



The Oak-pruner (Elapkidion mllosutn). 

 When oak-pruner beetles occur in con- 

 siderable numbers the trees are made un- 

 sightly by the dead branches which later 

 fall to the ground. The damage is done 

 by the larvae, which bore in the twigs and 

 finally cut them off. As the larvae pupate 

 in the fallen twigs they should be gathered 

 and burned before the adult beetles issue. 

 This insect attacks many kinds of shade 

 trees, and sometimes may be injurious to 

 certain fruit trees also. 



On the Pacific Coast there is another 

 smaller borer, Agrilus politus, that attacks 



FIG. 244. Work 

 of oak twig-girdler, 

 Agrilus sp. (About 

 2/3 natural size.) 



and kills the small branches of the oak trees. As the twigs 

 are killed, but not cut off, the tree soon becomes very ragged 

 and unpleasing in appearance. Such infested twigs should be 

 cut off some time during the winter. 



33 



