194 STATE BOARD OF AGRICULTURE. 



PBEPABATION OF INSECTICIDES. 



Any one of a number of arsenical sprays may be used in connection with 

 bordeaux mixture for the codling-moth, but paris-green is rather a favorite with 

 the writer because of its cheapness and because its color does not permit It to 

 be mistaken for flour, baking-powder or any other common household commodity. 

 In the case of large growers, the cost of paris-green would be considerably more 

 than Kedzie mixture or of white arsenic and lime. Directions for making these 

 insecticides can be found in special bulletin 24, which is to be had for the asking. 

 Disparene is purchased ready prepared and is said to have a great advantage in 

 that it sticks longer than paris-green or any of the other arsenicals. Its cost is, 

 however, somewhat greater. 



The writer makes bordeaux and paris-green as follows: Four pounds of copper 

 sulphate (blue vitrol) are dissolved in a wooden pail filled with hot water, and 

 six pounds of stone lime (quick-lime) are slaked as finely as possible in a metal 

 pail, with hot water. When ready stir the contents of each pail in a separate 

 barrel containing twenty gallons of water. Now pour one pailful at a time, into 

 a spraying barrel, taking alternately from these two half filled barrels, stirring 

 well all the time. In this way a bordeaux of fine quality is made. To prepare the 

 paris-green, place one-fourth to one-half pound of the unslaked lime in a small 

 pail or crook and slake it with hot water. When reduced to the consistency 

 of cream, add one-fourth pound of paris-green and stir with care, while the lime 

 is hot. Add this to the forty gallons of bordeaux, stir in well and spray. 



The copper sulphate should always be kept in wood as it quickly spoils if it 

 comes in contact with metal. The easiest way to dissolve it is to suspend the 

 crystals in a cloth bag just under the surface of the water. It dissolves much 

 faster than if placed on the bottom of the vessel. When large quantities are 

 to be made, it is well to make up a stock solution, dissolving a pound of the 

 sulphate in each gallon of water in a separate barrel, so that a gallon of the 

 liquid contains a pound of the crystals, in each case. This saves time, for we 

 simply have to dip out four gallons of the stock solution, dilute to twenty gal- 

 lons, and proceed as before. Several crocks or small pails may be kept going 

 all the time, so as always to have a prepared stock on hand. 



When large tanks are used of course larger amounts must be used, in the same 

 proportion. 



Use a fairly fine nozzle like a Vermorel, and stop spraying just before the tree 

 commences to drip. When using the paris-green alone, mix with freshly slaked 

 hot lime as described, only put it directly into forty-two or three gallons of water 

 i^istead of forty gallons of bordeaux. 



