46 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 



fruit trees are used, but it is advisable in most cases to reduce their 

 strength about one-fourth to one-third, especially if the fruit is well 

 matured on the trees. The materials used are chiefly oil emulsions, 

 miscible oils and soap powders, although the rosin wash and the 

 distillate-caustic soda-water mixture have also been used with success. 

 The oil emulsions may be prepared at home or purchased from reliable 

 manufacturers. Many growers, realizing the difficulty of securing 

 proper materials for home preparations and the variability of the 

 homemade mixtures, even under the best conditions, prefer to buy 

 manufactured products, especially when only small quantities are 

 needed. For those who desire a homemade product the following 

 formula may be followed for a crude oil emulsion i 1 



Crude oil (21 to 24 Baume) 15 gallons 



Liquid soap (or 20 Ibs. hard fish oil soap) 3 



Water 175 



Place the required amount of water in the spray tank and add the liquid soap ; 

 agitate thoroughly and pour in the crude oil, continuing the agitation until the 

 mixing is complete and no free oil remains on the surface and also during the 

 application to the trees. 



The distillate-caustic soda-water mixture is easily prepared as 

 follows : 



Distillate (28 Baume) 7 gallons 



Caustic soda (95%) 5 to 7 pounds 



Water to make 200 gallons 



First dissolve the caustic soda in a small amount of water and add to the 

 water in the spray tank; begin the agitation and slowly add the distillate, con- 

 tinuing the agitation during the application. This spray will also remove the 

 lichens or moss from the trees. 



The rosin wash is chiefly used for young and tender nursery stock, 

 because it does not cause the injury often following the application 

 of the previously named materials in such cases. The preparation is : 



Eosin 10 pounds 



Caustic soda (76% to 95%) 3 to 2% 



Fish oil 1% 



Water to make 50 gallons 



To a gallon of hot water in an iron kettle add the fish oil and the rosin and 

 heat until the latter is softened; after first dissolving the caustic soda in a small 

 quantity of water add it and stir the mixture thoroughly, after which pour in 

 enough water to make fifty gallons of spray material. 



i All of the spray formulae are reduced to meet the average needs for olive 

 trees. They may be strengthened by one-fourth to meet extraordinary conditions. 



