EXPERIMENT STATION BULLETINS. 397 



The commercial brands of arseuate of lead noAv on the market contain 

 from thirteen to twenty per cent of arsenious oxide and hence when 

 used at the rate of one pound to fifty gallons of Avater furnish about 

 the same amount as when Paris green is used at the rate of five ounces 

 in fifty gallons. It is moi-e effectual, however, when two pounds to the 

 same quantity are used, and when the cliewing insects are very large 

 and quite numerous, it is often advisable to use three pounds in fifty 

 gallons. For some insects like the rose chafer, which often appear in 

 great numbers and die slowly, tlie use of five pounds, or more of 

 arsenate of lead is recommended. 



Arsenate of lead has the advantage over other arsenicals of having 

 gi'eater adhesive properties so tliat it is not as readily washed off by 

 rains, and it can be used upon the most tender foliage without injuring 

 i1 even though no lime is added. 



Although the cost when two or three pounds are used in fifty gallons 

 is somewhat more than that of Paris green, when the amount of arsenic 

 contained is considered, the expense is little, if any, more. 



^ 



WHITE ARSENIC. 



As Paris green is quite expensive and is sometimes adulterated, 

 white arsenic is frequently used in its place. Its cost is about one- 

 third that of Paris green, and, as it is nearly twice as effective, tJie 

 expense is only one-sixth as much as when Paris green is used. To 

 ])repare arsenic for use the following treatment is necessary : In two 

 gallons of water place two pounds of freshly slaked lime and one pound 

 of arsenic; after boiling thirty to forty minutes the arsenic will have 

 dissolved and united with the lime, so as to form an insoluble com- 

 ])ouud. When desired for use the arsenic should be diluted, and one 

 jjouud prepared as above will suffice for two to three hundred gallons 

 when used upon fruit trees, or one hundred fifty gallons for spraying 

 potatoes. That there may be no injury to tlie foliage, it is desirable to 

 use the arsenic thus prepared either with Bordeaux mixture or lime 

 water. When lime water is used, one })ound of lime Avill be sufficient 

 for twenty gallons of water. 



LIME AND SULPHUR MIXTURE. 



(For San Jose Scale.) 



Lime (unslaked) 15 to 25 pounds 



Flour of Suli)liur 15 pounds 



Water 15 gallons 



Boiled one hour and diluted to fifty gallons. 



The best remedy that has been found for the San Jose Scale is su]])liur 

 and lime prepared after the above formula. Where one has only a few 

 acres of orchard to spray a jacketed iron kettle will answer for cook- 

 ing the spray mixture. Place ten or (if teen gallons of water in a kettle 

 and as soon as it boils add the lime. Fifteen |)ounds will answer if 

 unslaked but the amount should be increased if much of it has become 

 air-slaked. The maxinuim amount given above will not \>e excessive 

 and as it will serve to whilcMi the trees and show the thoroughness of 

 the spraying, it is often advisable. Make a paste of the sulphur and 

 turn it into the kettle or sift it in slowly. The sulphur and lime should 

 be thoroughly stirred Avhile the lime is slaking, and occasionally until 



