230 Report of the Horticulturist. 



When applying the mixture with pumps that have rubber balls 

 for valves, it must not be forgotten to replace the balls with 

 marbles as the kerosene soon destroys rubber. There is a large 

 amount of whale oil soap of poor quality on the market which 

 accounts for trouble that some people experience in forming 

 the emulsion. Only the better grades of whale oil soap should 

 be used. 



Paris green. — Paris green is used to poison insects that have 

 biting mouth parts. It may be applied either in the dry form 

 or in a spray. When the spray is used the Paris green may be 

 combined with Bordeaux mixture, or it may be applied mixed 

 with water. In either cases the same amount of poison is used. 

 For pomaceous fruits, such as apple and pears, one pound of 

 Paris green to one hundred and fifty or two hundred gallons is 

 commonly used. For stone fruits the mixture should be weaker, 

 using one pound of Paris green to two hundred and fifty or three 

 hundred gallons. When used with water, two pounds of fresh 

 slaked lime must be added for each pound of Paris green, to 

 prevent injury to the foliage. 



The adulteration of Paris green has come to be a great source 

 of annoyance and loss to the farmer and fruit grower. There 

 should be but one grade of Paris green and that the pure article, 

 yet many dealers have different grades for sale. The cheaper 

 goods must necessarily be adulterated. Where adulteration is 

 suspected, if some of the poison is crushed between two pieces 

 of window glass or between the thumb and finger, oftentimes 

 the small lumps will be found to be white inside, showing that 

 some adulterant has been used. The ammonia test which is very 

 simple though not infallible may also be used. Pure Paris green 

 will readily dissolve in ammonia and the solution will be of a 

 deep blue color. If there is any residue, or if the solution does 

 not become blue at once, adulteration may be suspected. 



