DIPPING AND FUMIGATION OF NURSERY STOCK 29 



kerosene. For a dormant spray one part of mixture is used to five or seven 

 parts of water. 



DISTILATE EMULSION 



Distillate (28 Baume) 20 gallons 



Whale oil soap 20 pounds 



Water 12 gallons 



Dissolve the whale oil soap in the water, which should be heated to the 

 boiling point, add the distillate and agitate thoroly while the solution is 

 hot. For dormant use, add 20 gallons of water to each gallon of stock 

 emulsion. 



Method of using. The miscible oils may be used upon all types of 

 sucking insects and also upon the chewing Insects where it is desirable to 

 kill them with a contact spray. The best results are obtained by using a 

 spraying machine when treating trees in the field, either a power or hand 

 pump, and give the trees a thoro spraying. When used for scale insects 

 it must be applied during the dormant season. It may be used as a dor- 

 mant spray upon nursery stock, but more generally when nursery stock is 

 treated for scale with a miscible oil, a tank is constructed, the tank filled 

 with the oil at the desired strength, and the trees dipped. It is the general 

 belief that the oil is not good for the roots of a plant and the tops only 

 are dipped. 



Chemical composition of miscible oil. The alkali in the soap or other 

 emulsifier reacts upon the oil in such a way as to cause it to break up and 

 become miscible in water. The commercial preparations are presumably 

 composed of different types of oils treated in different ways and are pro- 

 tected by United States patents. 



RESULTS OF EXPERIMENTS WITH MISCIBLE OIL 



Owing to the fact that miscible oils are used to some extent in con- 

 trolling San Jose scale 'upon fruit trees and, that in some states nursery- 

 men are allowed to use it instead of hydrocyanic-acid gas upon nursery 

 stock, an effort was made to determine its efficiency for controlling the 

 scale, Some of the nurserymen who use a miscible oil to dip their stock 

 say that it controls the scale just as well, if not better, than hydrocyanic- 

 acid gas; that it is not so costly, and that there is less danger of injury 

 to the tree. Also, like lime-sulphur, it is non-poisonous. 



Procedure. The larger nurserymen who make a practice of dipping 

 their stock, usually construct a large cistern-shaped vat of concrete or use 

 a large tank which they fill with the solution and in which very large trees 

 can be dipped. In this work the same trough was used as with the lime- 

 sulphur and in every detail the methods of procedure were the same with 

 the exception of the solution. With the first two sets of trees treated, 

 1 gallon of oil was used to 15 gallons of water; with the third and fourth 

 sets, 1 gallon of oil to 13 gallons of water was used. 



Effect of miscible oil upon San Jose scale on apple. The following 



