FORTY-FIRST ANNUAL REPORT. I75 



spray. The pails or crocks can be used one at a time and refilled occa- 

 sionally so tliat the stock is always on hand ready for use. 



ARSENATE OP SODA — KEDZIE FORMULA. 



This form of poison was originated at this Station by the late Dr. 

 R. C. Kedzie. 



This is a cheap effective poison that can be prepared at home. It 

 is used by many of the grape growers of Michigan in combination with 

 the bordeaux mixture. It cannot be used in the lime-sulphur sprays. 

 If used alone — as is sometimes done for potato bugs — slaked lime must 

 be added or the foliage will be burned. 



The formula is : 



White arsenic 2 pounds. 



Sal Soda (commonly called washing soda) 8 pounds. 



Water 2 gallons. 



Boil these materials in any iron pot or kettle not used for other pur- 

 poses for about 15 minutes or until the arsenic dissolves, leaving only 

 a small muddy sediment. Put this solution into a jug or other vessel 

 that cau be closed tightly and label "Poison." 



One quart of this solution is equal to Y2 pound of Paris Green, For 

 most spraying one quart in 50 gallons of water (with some lime) or bord- 

 eaux mixture will be sufficient. 



CONTACT INSECTICIDES, FOB INSECTS THAT SUCK. 



KEROSENE EMULSION. 



Place two gallons of ordinary kerosene in a warm place, either in 

 a warm room or in the sun, and allow to become as warm as possible 

 without danger from fire. Boil one pound of lauudrj' soap or whale-oil 

 soap in a gallon of soft water until completely dissolved. Eemove tlie 

 soap solution from the fire, and while still boiling hot, add the kerosene 

 and agitate vigorously for ten minutes, or until the oil is emulsified, 

 with a spraying pump by forcing the liquid back into the vessel from 

 which it was pumped. When the liquid is perfectly emulsified it will 

 appear creamy in color and will flow evenly down the side of the vessel 

 when allowed to do so. Care should be taken to completely emulsify the 

 oil and this is accomplished much more easily when the mixture is hot. 

 This strong emulsion may now be readily diluted with water and used, 

 or it may be stored away for future use. When cold it becomes like 

 sour milk in appearance and should be dissolved in three or four times 

 its bulk of hot water before diluting with cold water. If the water 

 is at all hard, "break" it by adding a little sal-soda before putting in the 

 soap. 



Small amounts of this emulsion may be made by using the ingredients 

 in small quantities but in the same relative proportion. It is used at 

 the rate of eight or ten parts of water to one part of emulsion. 



