176 MASS. EXPERIMENT STATION BULLETIN 179. 



(c) Steps in the preparation of stock solution follow: — 



1. Put the required amount of hot water in the container. 



2. Shave the Ivory soap into this and stir until completely dissolved. 



3. If at this time the temperature of the soap solution is too hot for 

 the hand to bear, dilute with 1 gallon of cold water and let it stand until 

 about body temperature or lukewarm. The cooling of this solution is 

 necessary in order to prepare a permanent emulsion; otherwise the oil 

 will come to the surface on standing (see No. 6). It also prevents the 

 chemical and physical killing properties of the linseed oil from being 

 changed by heat. 



4. Add slowly, whUe stirring vigorously, 1 gallon of linseed oil. 



5. Completely emulsify by using the bucket pump. Pump the emulsion 

 from the container through the pump and back into the container again, 

 keeping the nozzle below the surface of liquid. Five minutes' vigorous 

 pumping should completely emulsify this solution. 



6. Set aside for a few minutes while preparing spray tank in order to 

 see that oil does not come to the surface. 



[d) The following are directions for the preparation of spray tank and 

 spray: — 



1. Fill the 100-gallon spray tank about one-half full of water. If the 

 water used is too cold, upon the addition of the stock solution the soap 

 will solidify into small lumps, thus spoiling the emulsion. This may occur 

 early in the spring, when the water is very cold, but later in the season 

 ordinary tap water may be used without danger of the soap solidifying 

 on the addition of the stock solution. 



2. Add stock solution made above. (See (c) 1, 2, 3, 4, 5, 6.) 



3. Agitate. (If lumping occurs, the addition of a few pails of hot 

 water will remedy this.) 



4. Fill the 100-gallon spray tank. 



Application of the Spray. 



Outfits and Methods of Spraying. — In commercial greenhouse spraying 

 either a barrel pump or power sprayer should be employed, the latter 

 being the more economical, provided it is available and the size of the 

 establishment warrants its use. For spraying a few plants, or in a very 

 small greenhouse, perhaps the most satisfactory outfit consists of a com- 

 pressed air sprayer. 



The length of hose necessary in spraying cucumber houses depends 

 upon the size of the house and the method of growing cucumbers. If 

 the vertical trellis system is used, in most cases it is best to have the 

 hose of sufficient length to reach from the sprayer down the middle aisle 

 and across the opposite end of the house, thus eliminating the necessity 

 of changing the sprayer during the spraying operations. By passing in a 

 zigzag manner across the house and gradually working backward the 

 house may be thoroughly covered in the least amount of time. If cucum- 

 bers are grown on the "A" trellis sj'^stem the man spraying should travel 



