370 Diseases of Truck Crops 



Potassium sulphide is effective only if used imme- 

 diately it is prepared. It loses its value by being 

 exposed for any length of time. 



Stickers 



It is well known that with some plants, such as 

 cabbage, spray mixtures cannot be made to stick. 

 The use of a sticker added to the spray mixture will 

 largely overcome this difficulty. A sticker may be 

 prepared as follows: 



Resin 2 pounds 



Sal Soda (crystals) . . . 1 pound 

 Water 1 gallon 



The resin and the sal soda should be added to one 

 gallon of water and boiled in an iron kettle for one 

 and a half hours until clear. For plants which are 

 hard to wet, such as cabbage, or onions, the amount 

 of the sticker given above should be used for each 

 fifty gallons of Bordeaux or ammoniacal copper car- 

 bonate. For other plants, this amount is added to 

 each one hundred gallons of the spray mixture. 



Principles Involved in Spraying 



It should be remembered that to destroy chewing 

 insects, such as caterpillars, etc., the stomach poison 

 must be evenly distributed all over the plant. This 

 thorough spraying should be done as soon as the 

 presence of the pest is suspected. Intelligent and 

 observant growers will remember the time of ap- 



