204 EXPERIMENTAL FARMS 



3-4 EDWARD VII., A. 1904 



caterpillars. This must, however, be done before the caterpillars reach full growth, or 

 the work is useless. I have known of one instance where a municipal body with all 

 good intentions employed a man to cut out all of the webs of this insect and those of 

 the Tent Caterpillar in winter time, under the supposition that by this means they 

 were controlling those enemies. It is true the trees were more sightly when these nests 

 had been removed; but the operation in no way affected the abundance of the species 

 the following summer, because the caterpillars only live in the nests until nearing full 

 growth, when they leave them and pupate or build their cocoons in other places. The 

 Tent Caterpillars pass the winter inside the eggs, which may be found on trees, and 

 the Fall Webworms as pupse buried in the ground. Prof. Lochhead reports ' that the 

 Fall Webworm was very abundant in western Ontario late in summer, not only on 

 shade trees, but on many kinds of fruit trees, and unquestionably did considerable 

 harm. On account of the scarcity of labour in rural sections, few attempts were made 

 to get rid of the ugly webs filled with caterpillars. Unless parasites thin them out very 

 much, there is every likelihood that the Fall Webworms will be very numerous next 

 season.' The Negundo Plant-louse (Chaitophorus negundinis, Thomas) was observed 

 as injuriously abundant in Wimiipeg, Kegina and Calgary, the shade trees, which are 

 largely Ash-leaved Maples, being much disfigured by the copious deposit of honey-dew 

 on the leaves, and the Sooty Fungus which grows upon it. These trees attracted swarms 

 of flies during the daytime and of moths at night. The remedy recommended for clear- 

 ing these trees was to spray them with kerosene emulsion, 1 to 9, or whale-oil soap, 

 1 pound in 6 gallons of water, with or without tobacco. The tobacco, however, adds 

 considerably to the killing value of the wash. The Spruce Gall-louse (Chermes abietis, 

 L.) has spread widely through the Dominion, and has been the cause of a good deal 

 of injury to spruce trees. In the forest, nothing can be done to check the spread of the 

 insect; but in the case of ornamental trees, good results have followed spraying with 

 a tobacco and soap wash. The Fall Cankerworm was very abundant and destructive 

 in the woods around Ottawa early last spring. The caterpillars were not quite full 

 grown on June 12 last, when the first heavy rains came, which broke the exceptional 

 drought which up to that time had prevailed throughout eastern Ontario. Previous 

 to that they had been literally swarming in many woods along the Ottawa river. After 

 the rains they suddenly disappeared, and the total absence of both male and female 

 moths in the woods in autumn was noticed by many. It is possible, therefore, that 

 there will not be a recurrence of this attack for some time. The Birch Skeletonizer 

 (Bucculatrix canadensisella, Cham.) did some harm to birch trees of all kinds again 

 last year in eastern Ontario. The attack, however, was not nearly so severe as in the 

 two previous years, nor was its work supplemented by that of the large aphis, 

 Callipterus mucidus, Fitch, and tie small green leaf-hopper, Empoasca smaragdula, 

 FalL, which for the last two years have perhaps done as much harm to trees on the 

 Central Experimental Farm as was done by the Bucculatrix caterpillars. On my 

 return to Ottawa on August 21 last I found the birch trees on the ornamental grounds 

 of the Central Experimental Farm attacked in some places by the Birch Skeletonizer 

 to such an extent that some trees looked about half clothed with foliage. These were 

 at once sprayed with a whale-oil soap and tobacco wash, which was quite effective, and 

 no further injury was done. Should this insect again occur, trees should be examined 

 in July and early August, and, if the small caterpillars or the round white pseudo- 

 cocoons in which the caterpillars pass their moults are seen in numbers, the trees should 

 at ouce be sprayed before the foliage is injured to a conspicuous extent. 



