87 



27. Cyanide of Potassium : 



One ounce to one gallon of water poured into a trench sur- 

 rounding a tree affected with Woolly Aphis or Black Peach Aphis 

 is an excellent remedy. Use two to five gallons of the mixture 

 according to the size of the tree to be treated. Too strong a 

 dose is apt to injure the tree. 



28. Hydrocyanic Acid Gas : 



Potassium cyanide (98%) 1 ounce 



Sulphuric acid (93%) 1 fluid oz. 



Water 3 fluid oz. 



Or 



Sodium cyanide (129%) 4 ounce 



Sulphuric acid (93%) 1# fluid oz. 



Water ; \ l / 2 fluid oz. 



Place water and acid in earthenware vessel and add cyanide. To 

 be used under tents or in tight rooms or boxes. This formula 

 is a standard dose for 100 cubic feet of space within a tent stretched 

 over a tree or nursery stock to be fumigated for Red or Purple 

 Scale. Three-fourths of this amount is right for Black Scale in 

 the fall months. In a tight building or tight box, one-half of 

 this dose is enough. In all cases leave exposed for one hour. 



For scale insects on citrus trees, maximum or Purple and Red 

 Scale dosage can be found by multiplying distance around by 

 distance over the top of tented tree and pointing off two places. 

 Example : 



Distance around Distance over 



40 feet x 20 feet 8 ounces cyanide 



For Black Scale reduce one-quarter. 



29. Resin Dipping Solution : 



Resin 20 pounds 



Caustic soda or lye 8 pounds 



Fish oil : 3 pints 



Water 100 gallons 



Boil resin and caustic soda in 50 gallons of water for one hour. 

 Dilute to 100 gallons. In use for dipping citrus nursery stock for 

 scale insects and Red Spiders. Kerosene emulsion and lime sulphur 

 also used for dipping deciduous nursery stock. 



