4o6 Diseases of Greenhouse Crops 



Bordeaux mixture must never be combined with 

 kerosene emulsion, carbolic acid emulsion, and mis- 

 cible oils. 



(d) Fotassium Sulphide. Like sulphur, this is 

 a valuable fungicide for the control of the powdery 

 mildew. The following strength is recommended: 



Fotassitim sulphide 4 ounces 



Water 10 gallons 



Potassium sulphide is effective only if used im- 

 mediately after 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 an adhesive added to the spray 

 mixture will largely overcome this difficulty. An 

 adhesive may be prepared as follows: 



Resin 2 pounds 



Sal soda (crystals) l pound 



Water i 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 solution given above should be 

 used for each fifty gallons of Bordeaux or ammonia- 

 cal copper carbonate. For other plants, this amount 

 is added to each one hundred gallons of the spray 

 mixture. 



