154 MINNESOTA STATE HORTICULTURAL SOCIETY. 



strainer into the pump barrel containing twenty gallons of water. 

 Stir constantly and for a few minutes after the materials are all in. 

 It is not safe to use this unless it has been tested to see if there is an 

 excess of lime. A convenient way and one that is fairly accurate 

 is to take a small amount of the mixture in a saucer, hold it up 

 near the mouth and blow into it. If a thin coating (scum-like) forms 

 on the surface it shows that the lime is in excess, and it is then 

 safe to use. 



Copper Sulphate Solution. — Copper sulphate (blue vitriol), i lb.; 

 water, 15 to 25 gallons. 



Dissolve the copper sulphate as described under Bordeaux mix- 

 ture. This is only used on dormant plants, as before the buds start 

 in the spring. Use the weaker solution on the plum. 



Potassium Sulphide Solution. — Potassium sulphide, 1 oz.; wa- 

 ter, 1 to 3 gallons. 



For mildews on gooseberry, currant, and for chrysanthemum 

 rust. This is easier to use than Bordeaux and for mildews works 

 very well. 



Paris Green; London Purple. Paris green or London purple, 

 1 lb. ; water, 75 to 200 gallons. 



It is advisable to add a little milk of lime to prevent the injury 

 from any free arsenic which may be present in the poisons. It is 

 dangerous to use these poisons on the plum. 



Hellebore. — Hellebore (fresh white), 1 ounce; water, 5 gallons; 

 or, hellebore, 1 pound; flour, dust, etc., 1 pound. 



Flour helps to hold the hellebore or Paris green on the foliage. 

 This should be used when the dew is on the plants. 



Kerosene Emulsion — Formula: y 2 lb. common bar soap, 2 gal- 

 lons common kerosene. 



Cut the soap into small pieces or shavings and dissolve in about 

 two gallons of hot water. While still hot, pour in the kerosene and 

 with the hand pump or syringe pump it back and forth until a thick 

 butter-like substance is formed. In this condition the kerosene is 

 divided into very minute globules and will be readily diluted <or 

 suspended in water. 



Before using, add water enough to make (A) 10 gallons of 

 emulsion or (B) 20 gallons of emulsion. 



(A) is to be used when the insects are in large numbers and the 

 foliage is known not to be easily injured by it. 



The potato scab may be largely prevented by planting clean 

 seed, and even diseased seed may be used provided it is treated as 

 indicated herein. When the seed and soil is free from the scab 

 germs, the crop will be free from scab. 



