REPORT OF TEE ENTOMOLOGIST AND BOTANIST 189 



SESSIONAL PAPER No. 16 



FOREST AND SHADE TREES. 



No extensive injury to forest or shade trees by insects lias come under my notice 

 during 1905, but there have been local outbreaks of some importance. In Alberta the 

 Forest Tent Caterpillar has again stripped aspen poplars, and mention has been made 

 of its work on maples and in orchards in Nova Scotia. There are also indications that 

 Tent Caterpillars are again on the increase in Ontario and Quebec. The Larch Sawfly 

 (Nematus ericlisonii, Hartig), which appeared in a few places last year upon the native 

 tamaracks and imported European larches, was this year much more abundant, and for 

 some hundreds of miles along the Canadian Pacific Railway between Ottawa and Lake 

 Superior had stripped the young tamaracks growing in the swamps along the railway. 

 Occasional mention was also made by correspondents of the work of this insect in the 

 Maritime Provinces. An insect which has not previously been recorded as doing harm 

 in Canada, the Larch Case-bearer, has this year been found in considerable numbers 

 at Ottawa on the European larch. The Negundo Plant-louse which has occasionally 

 been so numerous upon the cultivated and wild Ash-leaved Maples in Manitoba and 

 the North-west Territories, was again extremely abundant in some places this year. 

 The Cottony Maple Scale (Pulvinaria innumcrabilis, E-athvon), which for several 

 years has been abundant on the shade trees in some of the cities of western Ontario, 

 was during 1905 even more so than in previous years. The outbreaks of the White- 

 marked Tussock-moth, which in previous reports have been referred to in some On- 

 tario cities, and in Montreal, have attracted much public attention, and at last efforts 

 are being put forth by the municipal authorities in various cities to control these 

 destroyers of the public shade trees. In Vancouver Island, the oak-looi>er Therina 

 somniaria, Hulst, which was complained of as being abundant last year, during 1905 

 swarmed in countless numbers over the oak trees in the vicinity of Victoria, B.C., 

 and stripped them of their leaves. The Spruce Gall-louse was exceptionally abundant 

 in 1905, and requests for information as to its life habits and the possibility of its 

 becoming a desti'uctive enemy of Canadian spruces, came in from many correspondents 

 in all parts of the country. The ornamental cedars on the Central Experimental Farm 

 were very much disfigured by the mining larvse of a very small moth belonging to the 

 genus Argyresthia. The moths appeared at the end of June and were found flying in 

 clouds around all varieties of the American Arbor-vitse, or so-called Wliite Cedar. The 

 full life history and the exact identity of the species are not yet worked out ; but young 

 larvas were found in the twigs early in spring, the moths emerged in the latter half of 

 June, and the young larvse are at present in enormous numbers passing the winter 

 inside the small twigs. As yet, no parasites have been bred. What was apparently 

 thi,'- same species, was sent to me in 1899 by Mr. Thos. Ware, from Plattsville, Ont.^ 

 Writing of this occurrence, Mr. Ware says : ' The insects did my cedars considerable 

 damage in 1899 ;. and not only mine, but whole cedar swamps lost their green and looked 

 quite brown. The trees have since been slightly affected each year, but not to any 

 great extent. I saw a few of the insects this summer but the hedge has not suffered.' 

 The injury to ornamental shrubs, and there are many varieties of the white cedar 

 grown as such, has certainly been serious this year at Ottawa. So far, no remedies 

 have been tried. The Fir Sawfly, Lophyrus abietis, Harr., appeared upon cultivated 

 White Spruces in two or three places in Manitoba. Mr, T, C, Court sent specimens from 

 Petrel, Manitoba, and their work v/as noticed upon cultivated spruces around the gov- 

 ernm.ent ofiices in Winnipeg as well as in the sand hills south of Douglas, Man. This 

 insect occurs in troublesome numbers from time to time in Manitoba, but is easily 

 controlled by poisonous sprays if promptly applied as soon as the larvse are noticed. 

 A very similar larva, but probably of another species of sawfly, was sent to me by Mr. 

 n. H. Miller, M.P., from Hanover, Out., where it had been found in destructive 

 numbers upon a cedar (arbor-vitse) hedge which was much valued by its owner. 



