20 THE MONTHLY BULLETIN. 



PRELIMINARY REPORT ON SPRAYING OF EGGS FOR 



THE CONTROL OF THE PURPLE AND GREEN 



APPLE APHIDES OF CALIFORNIA. 



By Paul R. Jones, San Francisco, Cal. 

 INTRODUCTION. 



A large number of nursery trees, heavily infested with the eggs of 

 the green apple aphis, Aphis pomi, and purple apple aphis, Aphis sorli, 

 were used for experimental purposes during the season of 1914. Inas- 

 much as the owner of these trees, Mr. George M. Brown of San Jose. 

 California, did not care what became of them, and was desirous of 

 obtaining some information leading to the control of these aphides, it was 

 decided to try out a large list of contact insecticides with the view 

 toward controlling these insects during the egg stage. In connection 

 with this experiment, Mr. E. II. Siegler, of the United States Bureau 

 of Entomology, rendered assistance. 



Aldrich in Bulletin No. 40, Idaho Experiment Station, 1904, was one 

 of the first to report success from a winter treatment against the over- 

 wintering eggs of plant lice. He obtained satisfactory results from the 

 use of homemade Lime-Sulphur sprays, but was not successful with 

 kerosene emulsion. 



Gillette and Taylor in Colorado Experiment Station Bulletins Nos. 

 133 and 134 found homemade Lime-Sulphur specific gravity 1.065 and 

 homemade Lime-Sulphur 1.045, commercial Lime-Sulphur specific grav- 

 ity 1.055, and commercial Lime-Sulphur specific gravity 1.080, effec- 

 tive; also Black Leaf 4 per cent and 3 per cent in strength, effective. 

 Kerosene Emulsion proved useless except when applied so strong as 

 to make it impracticable for use. 



Later, in the Journal of Economic Entomology, Vol. HI, No. 2, 

 April, 1910, pp. 207 to 210, Gillette reported Kerosene Emulsion of no 

 avail against several species of aphis eggs where less than 25 per cent 

 oil was used. 



Several eastern soluble or miscible oils which were used from 5 per 

 cent to 25 per cent in strength gave varying results, but eggs hatched 

 from all the strengths used. He also obtained good results with strong 

 whale oil soap against the eggs when used at the strength of one pound 

 and also two pounds to the gallon of water. Both homemade and com- 

 mercial Lime-Sulphur solutions gave fair results, the eggs hatching in 

 many instances, but the young dying while trying to extricate them- 

 selves from the eggshell or before taking food. 



He reported the best results from the various tobacco extracts. Black 

 Leaf 1 to 20 and 1 to 40 doing good work ; Nikoteen at strengths from 

 1 to 100 and 1 to 500 as effective; and with Sulphate of Nicotine at 

 strengths from 1 to 50 to 1 to 500 he had perfect results. Several 

 experiments of this product at 1 to 750 resulted in a few hatching. 



Nico-Fume at strengths from 1 to 50 to 1 to 1000 killed all the eggs 

 Avhile at 1 to 1200, 1 to 1500 and 1 to 1800 some hatched, more in the 

 cases of the weaker strengths. 



