THE CANADIAN HORTICULTURIST. 



gists. A short account of this destruc- 

 tive pest, as then known in Ontario, ap- 

 peared in the annual report of the 

 Clerk of Forestry for the Province of 

 Ontario for 1897. Since then it has 

 spread with astonishing rapidity and has 

 been detected at many points, from 

 Peterborough to the county of Bruce, 

 where it_ was lately detected by Dr. 

 Hunter on native spruce trees in a 

 swamp in the township of Culross. It 

 has also been found on native spruces 

 in Muskoka, near Utterson Station. So 

 far it would appear that unless this in- 

 sect is checked by some artificial means 

 it will soon destroy our ornaniental 

 spruce trees and hedges and, extending 

 northwards, do immense injury to our 

 spruce forests. 



The trees already attacked by this 

 spruce gall-louse in Ontario are the 

 European spruce, Picea excels a, the 

 double spruce or black spruce, Picea 

 nigra, the white spruce, Picea alba, and 

 the balsam fir, Abies balsamea, and it 

 may also be found on the hemlock, 

 Tsuga Canadensis. This insect is native 

 to Northern Europe and was introduced 

 into the United States on imported 

 spruce trees and thence into Ontario, 

 or it may have been introduced 

 here direct from Europe, as for many 

 years there has been an annual importa- 

 tion of young European spruce trees 

 into Ontario 



At Toronto the full grown insects — 

 the producers — emerge from the galls, 

 the scales of which open to give them 

 exit, about August ist. On emerging 

 they are slightly imperfect, but in one 

 day ample wings are developed which 

 enable them to fly long distances. 

 After distribution the female settles on 

 a spruce leaf and lays — under herself — 

 about thirty five eggs and then dies, 

 resting on the eggs. In about a week 

 the young six-footed larvae are hatched. 

 They crawl about and find immature 

 buds into which they burrow and of 



course remain quiescent during the 

 winter. But in the following spring 

 their presence in the bud causes it to 

 develop into a " gall " instead of a 

 normal twig. The lice in the galls give 

 birth to other living lice so that about 

 thirty individuals are found under each 

 scale of the gall. The galls are usually 

 irregularly spherical and often more 

 than a half inch in diameter. When 

 growing they are of a yellowish green 

 color, but during the winter they assume 

 a reddish brown tint, which they retain 

 until the end of May, when they usually 

 fall from the tree. This is the usual 

 form of this gall but there is another 

 form, not a gall, in which the injury is 

 done in the leaf axils. As these insects 

 in the feeding stage are within the gall, 

 and the gall is perfectly water-tight, so 

 that no fluid can penetrate, poisoning is 

 out of the question, and as in the 

 migrating larval stage, they do not eat, 

 poison is equally useless. Of course in 

 this larval stage soap emulsions might 

 be of some use if applied abundantly at 

 the proper time. But without any 

 doubt the cheapest and best plan as yet 

 tried in Ontario is to clip off the galls as 

 soon as they are noticed — say in June — 

 and always before the first of August, 

 while the producers are in the galls, and 

 immediately burn them up. When a tree 

 is too much infested to be dealt with in 

 this way it should be cut down and 

 burnt at once. Of course there is no 

 use in doing this after the producers are 

 out of the galls. Several cases aie 

 known where this plan was carried out 

 with very satisfactory results, and it is 

 respectfully recommended that all those 

 having spruce trees in charge should 

 carefully see to the clearing of their 

 trees and the extermination of this for- 

 midable insect pest. As some of our 

 nurseries are affected, buyers of ever- 

 green nursery stock should be very care- 

 ful to see that the young trees are per- 

 fectly free from this insect pest. 

 70 



