SwAiNE (J. M.). Forest Insect Conditions in British Columbia — Dmnin. 

 Dept. Agric, Div. Entom., Ottawa, Bull. no. 7, 40 pp., 1 map., 22 figs. 



This is a detailed account of the chief damage to timber due to 

 insects in British Columbia. Pinus ponderosa, Laws., which occurs 

 in the southern part of the interior, is seriously attacked by Dendroc- 

 tonus brevicomis, Lee, D. monticolae, Hopk., and D. valens, Lee. 

 [see this Review, Ser. A, i, pp. 406-407]. D. brevicomis passes the 

 winter in the middle layers of the bark of recently infested trees and 

 the adults appear in large numbers from June onwards. When green 

 trees are attacked the exuding resin forms gum-tubes about the mouths 

 of the entrance-holes, the presence of which indicates infestation before 

 it is otherwise recognizable ; yellowing and, later, reddening of the 

 foliage takes place from the middle of August onwards. Before the 

 foliage becomes red, the beetles will already have left the trees. 

 D. monticolae, Ho^\., IS found injuring the same trees as D .brevicomis ; 

 the broods are found in the inner bark and are exposed when the bark 

 is removed. D. valens, Lee, is found in stumps and dying trees of bull- 

 pine (P. ponderosa), Engelmann's spruce, and probably other pines and 

 spruces ; it is less destructive than the two former species and commonly 

 breeds in the bark of stumps and in the bases of trees dying from other 

 injuries, though it is known to attack and kill apparently healthy 

 trees. It occurs in Canada from the Yukon and British Columbia 

 to Newfoundland and Nova Scotia, throughout the eastern and western 

 United States and the West of Mexico. The number of infested trees 

 in Princeton increased from 10 in 1911 to 139 in 1913, in five isolated 

 areas where counts were made ; there appeared to be no effective 

 natural controls present, though bark-beetles are preyed upon by 

 various parasitic and predaceous insects, as well as fungi and insect- 

 feeding birds. When a serious bark-beetle outbreak is indicated, 

 before control measures are adopted, an exact determination of the 

 species concerned should be made by a forest entomologist. The 

 infested trees should be marked for cutting and a rough map made 

 to locate the badly infested parts. If mills are not available for the 

 profitable use of the timber, or if it is impossible to saw all the infested 

 logs within the time limit, i.e., before the 1st of June, a sufficient 

 number should be cut and barked and the bark burned before this 

 date. Infested timber which cannot be Hsed for lumber should be 

 cut and barked or burned in winter. The object should be to destroy 

 the broods in as many of the infested trees as possible, and if over 

 three-fourths of the infested trees of a district can be handled in winter, 

 the outbreak will be checked for several years, and further work on 

 the same lines the following winter should bring it under control. 

 When D. valens occurs, the infested stumps should be barked before 

 spring, but if D. monticolae only is involved, the removal of the bark 

 from infested trees in winter and spring is sufficient. The following 

 are minor enemies of P. ponderosa : Ips integer, I. emarginatus, 

 I. inter punctus, and I. oregonis. 



Pinus monticola, which occurs from the valley of the R.. Columbia 

 to Vancouver Island, is attacked by various bark-beetles, particularly 

 D. monticolae, in the interior and on Vancouver Island. There has 

 been an outbreak of this in Vernon District for about eight years, 

 resulting in the destruction of much of the timber, the infested trees 



