DISEASES OF CITRUS TREKS ] 95 



should be in the proportion of 5 litres of the concentrated 

 or condensed mixture to 100 litres of fresh water. For 

 winter use the proportion may be 8 or 10 litres of the 

 condensed mixture to 100 litres of water. 



Crude carbolic acid or oil of creosote dissolved in 

 strong alcalies or solutions of soap, make a good 

 emulsion which is a very efficient remedy against the 

 scale insects, but should be prepared and used with great 

 caution. If globules of either carbolic acid or of oil 

 of creosote are allowed to remain not emulsified they 

 will scorch the foliage and also the bark of the 

 green twigs. To prepare this emulsion dilute the oil of 

 creosote or the crude carbolic acid with twice its volume 

 of soap solution made by dissolving i kilog. of common 

 soap in 10 to 15 litres of hot water, and mix thoroughly 

 to dissolve the oil. When about to be used add 20 parts 

 of water to one part of this solution and apply in a fine 

 spray. The strength of this solution is one in sixty. 



Hubbard gives a good formula for kerosene emulsion 

 which he considers as the best for general use. It 

 consists of 2 gallons of kerosene, half a pound of common 

 soap and one gallon of water. The soap is dissolved 

 in the gallon of water, and added boiling hot to the 

 kerosene. The whole is thoroughly mixed for 10 minutes, 

 and a creamy emulsion is formed which thickens on 

 cooling. For use, dilute the emulsion with water in the 

 proportion of one to nine. This formula gives 3 gallons 

 of emulsion and makes, when diluted, 30 gallons of wash. 

 The application of this wash is said to be not injurious to 

 the tender growth of the tree, when applied in a cloudy 

 day or in the evening. It is much used in the United 

 States and is said to be very effective against most species 

 of scale. 



Pythelein, a soluble oil of tar, is readily mixable 

 with water in all proportions, forming a homogeneous 

 milky liquid of great stability which is said to be very 

 effective against the scale insects. The line of treat- 



