INSECT DAMAGE IN THE NATIONAL. PARKS. 5 



50 cents a tree for the required treatment. After an outbreak is 

 under control the living timber can be easily protected from further 

 depredations by giving prompt attention to the felling and barking 

 of any clumps of dying trees found during May and June. Rangers 

 or fire patrolmen can be instructed so that they can do this and any- 

 thing else that is required to maintain control. 



THE WESTEKN PINE BEETLE. 



The western pine beetle attacks the Avestern yellow pine, the sugar 

 pine, and the Jeffrey pine. The beetles fly in late June to October, 

 inclusive, and usually attack scattering individual trees, often select- 

 ing the larger and older examples. The adults excavate winding 

 egg galleries between the inner living bark and the wood and trans- 

 form to the adult stage in the outer bark. The beetles begin to fly 

 and attack the trees in June and continue the attack until October or 

 November. The first generation develops and emerges in August to 

 November, and the second generation passes the winter in the trees 

 that are killed by it in the summer and fall. 



The foliage of the infested trees begins to fade and turn yellow in 

 a few weeks after the trees are attacked by this beetle. The summer 

 broods of the first generation leave the trees by the time the foliage 

 is reddish brown, but the overwintered broods do not emerge until the 

 following May and June, in some cases several months after the 

 foliage is brown. 



This species is next in importance to the mountain pine beetle 

 as a destructive enemy of the pine, and the two species often combine 

 in their attack. In this combined attack the western pine beetle is 

 a secondar^y enemy of the trees because it follows the attack of the 

 other species. When it is the primary enemy it is responsible for 

 the death of a few scattering trees each year throughout the forest, 

 which results in the accumulation of dead timber. * In the aggre- 

 gate, this accumulative loss is very extensive, involving, as it does, the 

 largest and best trees. 



The insect can be controlled and the living timber protected from 

 its ravages by felling the infested trees during the period between the 

 1st of October and the 1st of June and removing the bark from the 

 main trunks and burning it. It is necessary to burn the bark because 

 the broods of this species transform in the outer bark. They are not 

 destroj^ed by simply exposing the inner bark, as is the case with the 

 mountain pine beetle. 



THE JEFFREY PINE BEETT.E. 



The characteristic habits of the Jeffrey pine beetle are similar to 

 those of the mountain pine beetle, and therefore it requires the same 

 treatment. 



