HOW TO CONTROL THE PEAR THRIPS, 9 



Have the water boiling hot when put into the spray tank and add 

 the soap immediately while the agitator is running at a good speed. 

 When the soap is all thoroughly dissolved, pour in the oil slowly, 

 keeping the mixture well agitated while the oil is going into the tank. 

 When all the oil is in and well mixed, pump out through the nozzles at 

 good pressure (not less than 175 pounds) into storage tanks. 



No one should attempt to make this stock emulsion without a 

 power spraying machine, as thorough agitation and high pressure are 

 important requisites. Also, care should be used in having measure- 

 ments reasonably exact, the water boiling hot, and soap thoroughly 

 dissolved, before any oil is put in. This stock emulsion contains 

 approximately 55 per cent oil, and to make a 3 per cent emulsion use 

 5^ gallons of this stock in each 100-gallon tank. To dilute, first put 

 the stock emulsion in spray tank (have the agitator going), and then 

 add the water, keeping the agitator running all the time. This is 

 important with the commercial preparations as well as with the home- 

 made emulsions. For the combination sprays of oil emulsions and 

 nicotine solutions, the nicotine should be added last, that is, after the 

 oil emulsion has been diluted to the desired strength. These solu- 

 tions should not be mixed together without first diluting one of them. 



This concentrated emulsion will cost the grower about 5 cents per 

 gallon, as most of the various distillates used for spraying cost from 

 5 to 10 cents a gallon in drum lots. 



In the spraying season of 1910 many growers of Contra Costa 

 County experienced great difficulty in making emulsions that would 

 remain emulsified when diluted. Part of this trouble was due to the 

 varying degrees of hardness in the water, but more to the composition 

 of the oil, especially where the treated oils and in some cases ordinary 

 stove distillates were used. Even after these treated oils were emul- 

 sified by changing the amount of soap used and treating the water 

 to " soften" it, the result was not satisfactory, as the diluted emulsion 

 from this lacked the essential penetrating quality and had a tendency 

 to collect in large drops rather than to spread out in a thin film. 



Experiments conducted thus far indicate that success is more 

 uniformly obtained by using an untreated raw distillate 32° to 34° 

 Baume with comparatively high flashing point. Some of the treated 

 oils have given good results, but as a whole the untreated raw, straight 

 distillates, comparatively free from naphtha and with a high flashing 

 point, have given far better and more general satisfaction. 



Some of the oil companies, particularly in the Bakersfield and 

 Coalinga districts, put out raw short-cut distillates — that is, the first 

 distillate after the naphtha, gasolines, etc., have been removed. 

 This kind of oil when running 32° to 34° Baum^ should under all cir- 

 cumstances be given preference. The ordinary stove distillates 

 have not, as a rule, given as good satisfaction, possibly because they 



