REPORT OF EXPERIMENTS WITH RESIN COMPOUNDS ON 

 PHYLLOXERA, AND GENERAL NOTES ON CALIFORNIA 



INSECTS. 



By Albert Koebele. 



LETTER OF SUBMITTAL. 



Alameda, Cal., October 20, 1890. 

 Sir: I herewith submit report upon experiments, chiefly with resin compounds, on 

 Phy'loxera vastatrix, and observations made during the year. 

 Very respectfully, 



Albert Koebele, 



Field Agent. 

 Prof. C. V. Eiley, 



TJ. S. Entomologist. 



By your direction a series of experiments was carried on , chiefly with 

 resin compounds, upon the Phylloxera in Sonoma Valley during Septem- 

 ber and the beginning of October. 



In preparing the compounds the following were used : Bicarbonate 

 of soda, sal soda, and Greenbank's caustic soda, 98 per cent. Three 

 pounds are required of the former to dissolve 1 pounds of resin prop- 

 erly, or, in other words, to make a resin soap ; 1 pound of the latter is 

 sufficient to dissolve 10 pounds of resin or even 11, but I did not suc- 

 ceed in dissolving 12 pounds, as parts of the resin would always re- 

 main. In repeated and careful trials this could not be overcome. 



The results showed somewhat in favor of the bicarbonate of soda as 

 far as to destruction of the insects, but the price has to be considered. 

 Next to this seems to be the emulsion prepared with caustic soda, but 

 it is a difficult matter to decide which will work best without carrying 

 on an extensive series of trials. It is safe to say, however, that the 

 results will not vary greatly. 



One pound of resin was used to each 10 pints of compound, and 

 this again was diluted with water at a strength of 1 pound of resin in 

 2| gallons of water, up to 1 pound in 37 1 gallons of water— one part of 

 compound in thirty parts of water. This compound will, as has been 

 previously stated, do effective work on unprotected Aphids, i. e., such 

 as are not covered with cottony or mealy exudations, at one part in 



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