1913 ENTOMOLOGICAL SOCIETY. Ill 



In connection with Potato insects I would like to draw attention to the ap- 

 proach of the Colorado Potato Beetle {Leptinotarsa decemlirieata) to the boun- 

 daries of British Columhia. Some ten years ago this heetle became imported and 

 localized near a place called Nez Perce, in Idaho. It has now extended its territory 

 into Washington, so much so that the south-east corner of the state is generally 

 affected. An isolated report was received by Professor Melander, of Pullman, by 

 correspondence this summer describing an insect which left little doubt of its nature 

 on the presence of this 'beetle at a place called Metaline Falls, a point some ten odd 

 miles south of the British Columbia border line, in the Columbia River Valley, 

 opening into the Lower Kootenay country. If this report is correct we may expect 

 to receive reports of its presence in British Columbia in the near future, at any 

 rate it is in the same class as the Codling Moth and the San Jose Scale and may 

 be expected in the course of years under natural conditions. 



Except for another outbreak of the Californian Tortoiseshell butterfly ( Vanessa 

 calif ornica), in the Kootenay country, confining its depredations to the bush and cul- 

 tivated places, this about completes the record of my British Columbia notes on in- 

 sects occurring during the past six months. I hope in a few days to make out my 

 report on these same insects as mentioned much more fully and explanatory. 



AESENITE OF ZINC AS A SUBSTITUTE FOR, ARSENATE OF LEAD. 

 L. Caesae, B.A., B.S.A., Guelph. 



Arsenite of Zinc is a very fine whitish, fluffy powder, much lighter than Paris 

 Green. It contains approximately forty per cent, of arsenious acid, which is about 

 three times as much as Arsenate of Lead contains. It costs twenty cents a pound 

 f.o.b. and is manufactured by the California Chemical Spray Co., Watsonville, Cali- 

 fornia. For some years this company has heen testing the value of Arsenite of 

 Zinc, and claims that the results have been highly satisfactoTy. Prof. Melander, of 

 Pullman, Washington, in limited tests states that it gave excellent results against 

 Codling Mothf. Prof. Cooley, of Montana Agricultural Experiment Station, says 

 that in his experiments it controlled Potato Beetles as well as Paris Green did, and 

 that it is a very stable compound, no arsenical injury taking place to the crown or 

 bark of trees, even when wounds were made and bandages kept moist with the 

 mixture were applied. Arsenate of Lead and all other arsenicals tested caused more 

 or less injury when thus used.* 



Statements like these led me to make some tests at Guelph this year, and to 

 urge other parties in various parts of the province to co-operate so that a com- 

 parison of results might give some valuable information. 



The first test was for Codling Moth. Alternate trees in two old orchards were 

 sprayed with Arsenite of Zinc and Arsenate of Lead. A little over 1 lb. of the 

 the former to 40 gallons of dilute lime-sulphur (1.008 sp. gr.) was used and 3 lbs. 

 of the latter to the same amount and strength of lime-sulphur. In my absence my 

 colleague, Mr. A. W. Baker, did the spraying and took the necessary pains to see 

 that it was thorough. Examinations of the trees at various times throughout the 

 season showed that while both mixtures gave excellent results the trees sprayed 

 with Arsenite of Zinc were a little cleaner than the others, only very rarely an 

 apple being wormy. Unsprayed trees had much wormy fruit. 



Mr. Beckett, an extensive grower of apples at Hamilton, and Mr. J. E. Smith, 

 of Simcoe, co-operated in tests against the Codling Moth with Arsenite of Zinc. The 



i^lfetin No. 103, Agr. Expt. Sta. Pullman, Washington. 

 ♦Journal of Econ. Ent., Vol. 5, No. 2. 



