Forest Insect Investigation in British Columbia 



In response to a request for information 

 in regard to the work during the past sum- 

 mer in British Columbia Dr. C. Gordon 

 Hewitt, Dominion Entomologist, sends the 

 following: — 



' The forest insect survey in British Col- 

 umbia which was undertaken last year in 

 co-operation with the Provincial Forest 

 Branch, has been continued during the past 

 summer. Mr. J. M. Swaine, in charge of 

 Forest Insect Investigations, spent June and 

 July in continuing this work, and Mr. E. 

 N. Chrystal, Field Officer for Forest In- 

 sects, has been stationed in British Columbia 

 throughout the season. Our knowledge of 

 the districts infested and the extent of the 

 more serious outbreaks has been greatly 

 extended and valuable additional informa- 

 tion has been obtained in regard to the 

 habits of some of the destructive species 

 involved. We have also been making de- 

 tailed studies of the injurious insects which 

 have brought about the present unfortunate 

 conditions in Stanley Park, Vancouver. 



' It is found that the amount of dead 

 hemlock in Stanley Park is now much 

 greater than in September of last year, 

 many trees having died during the fall and 

 winter. The spruce trees along the drive- 

 ways are now so badly injured by the 

 Spruce Gall Aphid that few of them are 

 worth saving. Fortunately the greater part 

 of this foliage is hemlock and Douglas fir 

 and is still (August 1st) in fair condition. 

 The large spruce in the interior of the Park 

 are now attacked by the Sitka Spruce Bark- 

 beetle. This infestation is serious and con- 

 trol measures will be necessary this winter 

 if the remaining large spruces are to be 

 saved. 



' The dead timber in the interior of the 

 Park is chiefly hemlock and of this there are 

 large areas. The trees have been killed by 

 repeated defoliation by Therina caterpillars, 

 assisted by woolly aphides during the early 

 season. The caterpillars are not so numerous 

 this season and there is as yet little de- 

 foliation. It is possible that their parasites 

 have already obtained control and that the 

 worst of the outbreak is now over. If this 

 proves to be true the spraying which has 

 been recommended will not be so necessary 

 for the present. The dying and recently 

 killed trees are serving as breeding places 

 for injurious insects and fungi that will 

 later help to weaken and kill the healthy 

 trees. The Western Hemlock Bark-beetle, 

 a destructive species, is already established 

 in these dying trees. It will, therefore, be 

 necessary to remove and properly dispose 



of this dying and dead hemlock during the 

 coming fall and winter; and if the areas 

 thus denuded are reforested to Douglas fir, 

 the most healthy timber tree of the pro- 

 vince, such portions of the Park will be put 

 in perfect condition for all time. It should 

 be made a settled policy to replace the hem- 

 lock_ as it gradually dies, by the much more 

 healthy Douglas fir. 



' The Bark-beetle infestation in yellow 

 pine in the Okanagan district is more ex- 

 tensive than at this time last year and ap- 

 pears to be spreading rapidly. The amount 

 of new infestation for the present season 

 will 1)0 estimated later. The infested area 

 surrounds Okanagan Lake and extends as far 

 west as Princeton and Nicola. In the dis- 

 tricts which have been infested longest the 

 destruction is enormous. Above Peachland, 

 on Okanagan Lake, the yellow pine and 

 the black pine have been practically killed 

 ofl' l)y the beetles, and the hillsides appear 

 as though swept by a great fire, only the 

 islands and strips of Douglas fir remaining 

 green. This infestation of the yellow pine 

 and the black or 'jack' pine is a very 

 serious matter and timber owners in the in- 

 fested region and about its extending mar- 

 gin should take due precautions to check its 

 spread. Fortunately, such outbreaks can be 

 controlled, if taken in time, and under 

 favourable conditions in districts which can 

 lie lumbered profitably the control measures 

 do not involve much expense. 



' The infestation of Western white pine 

 by the Western White Pine Bark-beetle is 

 reported from additional localities this sea- 

 son. If present conditions continue the 

 white pine in many parts of British Colum- 

 bia will soon be entirely killed off. The 

 owners of any valuable stands of Western 

 Avhite pine should be on their guard against 

 this most destructive enemy. 



' The great loss already caused by the 

 Bark-beetle outbreaks and the apparent cer- 

 tainty of still greater destruction, demand 

 vigorous control measures in many districts. 

 The proper disposal of pine slash is a very 

 important factor, for the beetles frequently 

 breed to immense numbers in such abundant 

 supplies of breeding material and spread 

 thence into the green timber. It should be 

 a settled policy in British Columbia to burn 

 all pine slash each season 'between October 

 and May, as an aid to Bark-beetle control. 

 The activity of other species of Bark- 

 beetles in Spruce and Douglas fir will ap- 

 parently soon render the burning of spruce 

 and fir slash equally necessary. 



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