INSECTS INJURIOUS TO TREES 139 



cent of water should be insisted upon. This spray may 

 be used successfully against caterpillars and other leaf- 

 eating insects in the spring or summer. 



Whale-oil soap should be used at the rate of 1| pounds of 

 the soap to 1 gallon of hot water, if applied to the tree 

 in winter. As a spray in summer, use 1 pound of the 

 soap to 5 gallons of water. This treatment is useful 

 for most sucking insects. 



Lime-sulfur wash is an excellent material to use against 

 sucking insects, such as the San Jose" scale and other armored 

 scales. The application of a lime-sulfur wash when put on 

 during the dormant season is not likely to harm a tree 

 and has such an excellent cleansing effect that the benefits 

 to be derived in this direction alone are often sufficient to 

 meet the cost of the treatment. Lime-sulfur wash consists 

 of a mixture, boiled one hour, of 40 pounds of lime and 

 80 pounds of sulfur, in 50 gallons of water. It may be 

 had in prepared form and should then be used at the rate 

 of 1 gallon to about 9 gallons of water in winter or early 

 spring before the buds open. At other times of the year 

 and for the softer-bodied insects a more diluted mixture, 

 possibly 1 part to 30 or 40 parts of water, should be used, 

 varying with each case separately. 



Kerosene emulsion consists of one-half pound of hard 

 soap, 1 gallon of boiling water, and 2 gallons of kerosene. 

 It may be obtained in prepared form and is then to be used 

 at the rate of one part of the solution to nine parts of water 

 when applied in winter or to the bark only in summer. 

 Use 2 gallons of the solution to a 40-gallon barrel of water 

 when applying it to the leaves in the summer. Kerosene 

 emulsion is useful as a treatment for scale insects. . 



Tobacco water should be prepared by steeping one-half 

 pound of tobacco stems or leaves in a gallon of boiling water 



