EXPERIMENT STATION BULLETINS. 291 



Kerosene and Water Mixture. 



Fully as good results have been secured when the kerosene has been 

 formed into a mechanical mixture with the water, as when it is emulsified. 

 Within the last three or four years pumps for forming this mixture have 

 l)een made by The Deming Co., Salem, O., and The Goulds Co., Seneca 

 Falls, N. Y. They can be regulated to supply any proportion of oil that 

 is desired, and do good work. The amount of oil is practically the same 

 as w^hen an emulsion is made, i. e., one part of oil to three of water for 

 scale insects when the trees are dormant, seven parts of water to one of 

 oil for the same insects when the trees are growing, and fifteen parts of 

 water to one of oil for most of the soft-bodied, sucking insects. When 

 applied in this way, the cost of the materials and labor of preparing them 

 is much reduced, and, in addition to securing as good if not better results, 

 it has been found that the danger of injuring tender foliage is lessened. 



Pure kerosene and crude petroleum are also recommended for the de- 

 struction of scale insects; but as both of them, and the former par- 

 ticularly, require great care in their application, it is better to rely upon 

 the mechanical mixture with water. Kerosene should not be used upon 

 peach trees. 



Paris Green. 



Paris green 1 pound 



Water 100-200 gallons 



For the destruction of insects that eat the foliage or fruit, Paris Green 

 is a valuable remedy. It can be used in water in the above proportions, 

 the stronger mixture being used for potatoes, while for fruits it is seldom 

 advisable to use more than one pound in 200 gallons of water, unless 

 in connection with lime water or Bordeaux mixture. It is always advis- 

 able to first form a paste with a small amount of water when preparing 

 it for spraying. For low plants Paris green may be used in a powder 

 form either alone or with one hundred times its weight of plaster. Lon- 

 don purple is sometimes used in place of Paris green, but it is more apt 

 to injure the foliage. Green arsenoid and arsenate of lead are valuable 

 substitutes for Paris green. 



White Arsenic. 



As Paris green is quite expensive and is sometimes adulterated, white 

 arsenic is frequently used in its place. Its cost is about one-third that 

 of Paris green, and, as it is nearly twice as effective, the expense is only 

 one-sixth as much as when Paris Green is used. To prepare arsenic for 

 use the following treatment is necessary : In two gallons of water place 

 two pounds of freshly slaked lime and one pound of arsenic ; after boiling 

 thirty to forty minutes the arsenic will have dissolved and united with 

 the lime, so as to form an insoluble compound. When desired for use 

 the arsenic should be diluted, and one pound prepared as above will suffice 

 for two to three hundred gallons when used upon fruit trees, or one hun- 

 dred fifty gallons for spraying potatoes. That there may be no injury to 

 the foliage, it is desirable to use the arsenic thus prepared either with 

 Bordeaux mixture or lime water. When lime water is used, one pound of 

 lime will be sufficient for twenty gallons of water. Although the spray- 

 ing calendar does not refer to arsenic, it can be substituted for Paris 

 green, if desired. 



