ENTOMOLOGICAL SOCIETY OF ONTARIO. 6? 



It has been unusually dry with us, and in consequence our field is free from fungus 

 troubles, yet the contrast between the sprayed and unsprayed rows is most striking. On 

 the unsprayed rows every leaflet has from 50 to 500 flea beetle punctures, the plants are 

 pale and sickly, and are already beginning to shrivel trom the drought. The rows 

 sprayed with Bordeaux mixture are practically free from the flea beetle mutilations, vigor- 

 ous and thriftv. I have brought for your examination two entire potato plants taken from 

 adjoining rows, the one sprayed with Bordeaux mixture, the other not, which fairly repre- 

 sents these difierences. A few days ago two leaves were taken from each hill of these 

 two rows and carefully examined. An average of twelve flea beetle punctures per leaflet 

 was found on the row sprayed with Bordeaux mixture. On the adjoining row which had 

 received no Bordeaux mixture, but had been freely dusted with Paris green (1 pound 

 Paris green in 50 pounds land plaster) there was an average of 262 holes per leaflet. 



We therefore feel justified in advising the use of Bordeaux mixture on potatoes for 

 a neiv purpose, namely : As a deterrent against flea beetles. The use of Bordeaux mix- 

 ture as a fungicide has proved especially profitable with us during wet seasons. This 

 newly discovered virtue will warrant its use during the dryest seasons also, since the flea 

 beetles are most troublesome then. Judging from our experience this season, in Vermont 

 two applications of the mixture will sufiice to hold these beetles in check, and upon late, 

 potatoes one application will probably prove suflicient The first application should be 

 made upon early potatoes during the first week of June, and another about July loth. 

 This latter application is also well timed for the prevention of the fungus diseases of the 

 potato. Upon later potatoes the earlier application just mentioned is not necessary. We 

 may, therefore, say that practical immunity from flea beetle injuries to potatoes may be 

 secured at the cost of but a single application of Bordeaux mixture in addition to those 

 already recommended for the fungus diseases. 



Regarding the value of other fungicides tested, modified Eau Celeste has proved 

 nearly as efltecfcive a deterrent against these beetles as has Birdeaux mixture. All of the 

 other copper solutions tested have had similar deterrent eflfects roughly in proportion to 

 the amounts of copper contained. The inference, therefore, is that the copper salt is the 

 element especially distasteful to the beetles. Soap, when mixed with these fungicides 

 adds slightly to their value as deterrents, but not enough to justify its addition for 

 general use. 



THE GYPSY MOTH {Ocneria dispar, L.). 



By James Fletcher, Ottawa. 



Of the many injurious insects introduced at various times from the old world, not 

 one has, in as short a time, attracted so much attention, been so great a cause of anxiety, 

 or been so systematically fought as the Gypsy moth, since it appeared in vast numbers in 

 the State of Massachusetts in 1889. As a practical object lesson of the value of scientifi- 

 cally directed effort to overcome an insect enemy which had been allowed to increase 

 unnoticed until it had assumed almost overwhelming proportions, the campaign which has 

 been so successfully carried on for the last four years by the Gypsy Moth Department of 

 the State Board of Agriculture of Massachusetts is of very great interest to all economic 

 entomologists. 



Having recently passed through part of the infested region, my attention was 

 attracted to the trees bearing bands of burlap or marked with the various signs used by 

 the inspectors to denote that they had examined the trees. Since my return to Canada, 

 I have been favoured with a full series oE the excellent rep3rts of the Commission, together 

 with much other information as to the methods of work, which have been kindly fur- 

 nished by Prof. E. H. Forbush, the director of field work. On the whole, I think all 

 must acknowledge that, up to the present time, the efforts of the Commission have been 

 very successful ; but whether the enemy is entirely exterminated must depend upon 

 whether the work is continued in the same careful manner for at least a few years longer. 



fFor further details see Vt. Exp. Sta., Bui. 40, p. 25. 



