INSECTS AFFECTING OHIO SHADE TREES 199 



The kerosene and lime are mixed in the proportion of one gal. 

 kerosene to 41bs. lime, or in other words, the lime is added to the 

 kerosene until all the kerosene is absorbed. It requires from 3 to 5 

 minutes to thoroughly mix the mass. When the emulsion is 

 complete, it is diluted with water and applied. For scale insects, 

 upon which the mixture is most commonly used, the following- are 

 the proportions: kerosene 12/^ gal., lime 50 lb., water 34 /^ gal. 



Materials of this class require dilution with water 

 S:alectae ana only; usually 5 percent mixtures are recommended 

 ot/ier so-called . ,+ f f , *':* 



Soluble Oils y manufactures for scale applications. 



In the experience of Prof. P. J. Parrott of the . 



New York Experiment Station, mixtures containing 7 to 10 percent 

 of oil applied to trees infested with the San Jose scale, gave results 

 slightly inferior to those obtained from the use of boiled lime- 

 sulfur sprays. 



POISON SPRAYS. 



The poison sprays in most general use at the present time 

 are Arsenate of Lead and Paris Green. Of the two, the lead is the 

 mcst expensive but the extra expense is usually justified by reason 

 of its superior adhesive qualities and consequently longer period 

 of efficiency after the application. The Paris green is more quickly 

 effective than the lead. 



r r j This material is manufactured by a number of 

 Arsenate of Lead . . . . 



companies and is placed on the market under 



varying trade names. It is paste-like in consistency, requiring only 

 the addition of water before use. Some brands are with difficulty 

 dissolved, and for these the author has found the work of the 

 process of preparation much lessened by placing the paste in a 

 small burlap sack and, with frequent dippings in the spraying 

 mixtures, work the materials through the cloth. 



For most leaf-eating insects three pounds of material to 50 gal. 

 is sufficient, while for others 5 to 7 Ibs. to the same amount of water 

 is more desirable. 



Where it is impossible to obtain the manufactured article or 

 for any reason undesirable to do so, arsenate of lead may be 

 prepared after the following formula: 



Acetate of lead 11 oz. 



Arsenate of soda 4 oz. 



Water 50 gal. 



Dissolve the acetate of lead and arsenate of soda separately in 

 2 quarts of water each. Pour the two together and add the desired 

 amount of water. 



*Bulletin 28, New York Agricultural Experiment Station. 



