26 BULLETIN 308, U. S. DEPAKTMElsTT OP AGEICTJLTUEE. 



(6) The broods of the beetle in the bark of the main trunks of the medium 

 to larger-sized dying infested trees within an area of 8 or 10 square miles or 

 more must be destroyed in order to stop their depredations. 



(c) The broods may be destroyed by one or more of the following methods, 

 the work to be done between the 1st of November and the 1st of March : 



(1) Removing and burning the infested bark from the trunks of the stand- 

 ing trees; or 



(2) Removing and burning the infested bark from the trunks of the trees 

 after they have been cut down ; or 



(3) Scorching the infested bark or burning the wood with the bark after the 

 trees are cut down ; or 



(4) Placing the infested portions of the trunks in water; or 



(5) Converting the trunks of the infested trees into cordwood and using the 

 wood for fuel before the beetles leave the bark; or 



(6) Converting the infested trees into lumber or other products and burning 

 the slabs or bark. 



(d) It is not necessary to burn the tops or branches of treated trees or to cut 

 and burn small infested saplings if the larger infested trees are disposed of. 



(e) It is not necessary to remove or destroy the bark on the lower portion of 

 the trunk or on the stumps if it is not infested with the destructive beetle, and 

 it is not necessary to cut or treat dead trees from which the beetles have 

 emerged. 



(/) It is necessary and essential that the broods of the destructive beetle in 

 the bark of any portion of the main trunks of the medium to larger sized dying 

 infested trees of any given locality should be destroyed. 



(g) If the wood of the infested trees can be utilized for fuel, lumber, or 

 other purposes, its value should cover the cost of the work. If the work of 

 felling and barking the trees is done at direct expense, the cost will average 

 10 to 30 cents per tree. 



(h) The cost of protecting the living timber of any locality with average in- 

 festation should not exceed an average of from 1 to 5 cents per acre for the 

 total area of pine-covered land, and if estimated on a basis of volume it should 

 not cost over 2 cents per cord of the living timber protected. 



(i) The best time to conduct control operations against the southern pine 

 beetle is during the period between November 1 and March 1. 



(/) If a pine tree standing among or near a grove or woods of living pine is 

 either struck by lightning or felled and barked or split into cordwood during 

 the summer and early fall, it will, as a rule, attract the beetles within a radius 

 of 3 or 4 miles and result in the starting of a new center of infestation and in 

 the death of a large number of trees. 



(7c) The principal owners of pine in each community should cooperate in the 

 disposal of the required infestation, but should not undertake the work until 

 some one or more of the owners is sufficiently familiar with the essential details 

 of the proper methods. 



The pine tip moth {Retinia frustrana Scud.) attacks and deforms 

 the growing tips of branches. In some localities this is the most 

 noticeable cause of injury and is sometimes very abundant for several 

 successive years. There is no practical means of controlling the insect 

 under forest conditions. The injury is least in suppressed parts of 

 trees, or trees growing beneath older forest stands and greatest in 

 thrifty stands of reproduction from 4 to 10 years old growing in old 



