29 



wholly free from this pest. Nor is this an isolated case, since I saw 

 the same thing- in another pear orchard located several miles from this 

 one. Mr. Eichardson informs me, however, that the fruit of this tree 

 is almost worthless. 



Wishing to test the effects of the above wash on growing trees, I 

 sprayed a prune, peach, apricot, apple, and orange tree on the 12th day 

 of May, between the hours of 10 and 11 a. in., sun shining, light breeze. 

 I examined these on the 11th of June ; on the prune all of the fruit had 

 dropped off, and upon one- third of the leaves were dead brown spots, 

 these spots not exceeding one-sixth of the entire surface of any of the 

 leaves ; on the peach* all of the fruit was dead, but still clinging to the 

 tree, and half the leaves had brown spots in them, these leaves being 

 much more injured than were those on the prune tree ; on the apricot 

 the fruit was not injured in the least and three-fourths of the leaves 

 were uninjured, but the remaining leaves had small brown spots in 

 them, these spots not exceeding one-fifteenth of the surface on any of 

 the leaves ; on the apple all of the fruit had dropped off and half the 

 leaves had large brown spots in them, these spots sometimes exceeding 

 one-half of the entire surface of the leaf ; on the orange nearly all of 

 the fruit had dropped off (the young oranges being about half an inch 

 in diameter), but the leaves were uninjured. 



This indicates that of the different kinds of fruit thus experimented 

 upon the apricot was the hardiest and was the least affected by the 

 wash j next to the apricot is the orange, then the prune, after this the 

 peach, the apple having suffered most from the effect of the wash. 



The orange tree experimented upon was infested with the Yellow 

 scale (Aspidiotiis citrinus), and also with the Black scale (Lecanium olecv 

 Bernard), and all of these, as well as the eggs of the Black scale, were 

 destroyed by the wash. 



According to the scale of prices furnished me by the Los Angeles 

 Soap Company of this city, the material for making 100 gallons of the 

 above wash, when purchased in large quantities, would amount to $1.14, 

 being but a trifle over 1 cent a gallon for the diluted wash. 



The materials used in preparing the above wash are the same as 

 those I used in spraying orange trees last season for the destruction of 

 the Eed scale (Aspidiotus aurantii Maskell), an account of which is 

 given in my report to Professor Biley for last year, published in Bulle- 

 tin No. 22 of the Division of Entomology (pp. 10-14) ; but the spray I 

 then used was only three-fifths as strong as the one I used for the de- 

 struction of the San Jose scale as above described. On the 19th of 

 December I tested the spray of the same strength that I had used 

 for the Eed scale on orange trees, but it did not prove fatal to all of 

 the San Jose scales that it came in contact with. 



The question as to the manner in which the above resin spray proves 

 fatal to the scale insects—whether the caustic property imparted by the 

 caustic soda is the destructive agent, or whether it is the suffocating 



