THE EUROPEAN ELM SCALE I3ST THE WEST. 



15 



The results of these washing experiments have been previously re- 

 ported in considerable detail (9). 



SPRAYING EXPERIMENTS. 



Sprays consisting of distillate emulsion, kerosene emulsion, or 

 crude-oil emulsion at strengths varying from 3 to 5 parts water to 

 1 part emulsion proved entirely unsatisfactory for the control of the 

 European elm scale, only 20 to 60 per cent of them being killed. A 

 solution of 1 pound of fish-oil soap and 7 gallons of water was used 

 upon some molting females but was completely unsuccessful. Al- 

 though other experimenters have reported fair results from the use 

 of lime-sulphur, the writer's results with it were unsatisfactory, 

 practically none of the insects being killed. This material can not 

 be used in shade-tree work to any great extent because the sulphur 

 in it combines with the paint on buildings and turns it black. 



Fig. 5. — Washing 



large elm trees with water from fire engine to remove the European 

 elm scale. 



The best results were obtained from miscible-oil sprays. Those 

 containing 28° Baume oil were found to be very satisfactory, whereas 

 those containing 33° gave very poor results. The former were 

 efficient at the proportions of 1 part oil to 9 and 12 parts water, and 

 certain brands of them at the greater dilution of 1 to 15 parts water. 

 Miscible oil 28°, 1 part to 12 parts water, is the material to be re- 

 commended. 



RECOMMENDATIONS FOR CONTROL. 



Either of two materials is recommended for the control of this 

 insect, a solid stream of water or a miscible oil spray. The garden 

 hose and nozzle may be used to good advantage where a few small 



