314 



INJUmOUS INSECTS AND FUNGI. 



[March 1895. 



Bi-sulpliide of carbon, as used againsb the phylloxera, killed 

 wireworms, but it would require 1,000 lbs. of the liquid per 

 acre, so that it would only be practicable and profitable to 

 employ this on limited areas and for valuable crops. 



In extremely bad and persistent wireworm infestations of 

 hop land, it might be desirable to try bi-sulphide of carbon, but, 

 owing to its explosive nature, it must be very carefully handled. 

 This could be applied close to the " hills " or plant centres, 

 with the instrument known as the pal Gastine, resembling a 

 large auger, or borer, which is worked into the earth close to 

 the vine stocks. In the upper part of this instrument there 

 is a cylindrical case to contain the bi-sulphide of carbon. Upon 

 pressing a spring into this cylinder an exact dose of the insecticide 

 is injected into the hole made by the borer. In the vineyards 

 where this process is employed, the dose varies from one quarter 

 to half an ounce of bi-sulphide of carbon injected in two or 

 three places near each vine-stock. 



In order to destroy wireworms with salt, it would seem that 

 it must be applied at the rate of 10 tons per acre, and this 

 would be practically destructive to vegetation. Lime applied 

 at the rate of 200 bushels per acre, and gas lime at the rate 

 of 20,000 lbs. per acre, did not extirpate wireworms in the Cornell 

 experiments referred to above. 



Although " traps " were tried at Cornell without very con- 

 clusive results, it is to be noted that " traps " of rape cake^ 

 mangel-wurzel, potato, carrot, and turnip have been found of 

 great value in hop land, for instance, where almost the only 

 way to get rid of wireworms is by placing pieces of these 

 roots, or of rape cake, close round the hills or plant-centres. 



These traps of mangel, potato, or rape cake should be placed 

 close to the hills or plant-centres, about four or five inches 

 below the surface, and examined once or twice a week, and 

 the wireworms taken out and destroyed. The traps should 

 be continued during the spring and summer, and up to the 

 winter, in badly infested hop land, as the wireworms only go 

 down deep into the ground when frost comes, and the traps will 

 be more likely to be attractive when the hop plants are not 

 putting forth shoots. 



As it is rather difficult to find the " traps," white wooden^ 

 skewers with points and thick heads might be advantageously 

 used in the case of mangel, potato, turnip, and carrot traps, 

 to show where they are, and to enable them to be pulled easily 

 from the earth. 



There is no doubt that wireworms have been encouraged in 

 hop land by the quantities of rape ^«dust," or ground rape 

 cake, put on for manure, so that in infested fields it would be 

 well not to use rape cake as a manure for some time. 



Rape dust sown broadcast on wheat, oats, barlej^, and other 

 crops infested with wireworms, at the rate of from 5 to 7 cwt. 

 per acre, has frequently been the means of saving the crop, as 



