I 1 



INSECTS AFFECTING OHIO SHADE TREES 199 



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



kerosene to 4 lbs. 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 



Ci^aiectae ana „„i, . , „. n c ^ • , 



other so-called ^' "^"^.lly 5 percent mixtures are recommended 



Soluble Oils ^^ ^^^ manufactifres 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 ParisiGreen. Of the two, the lead is the 



most 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. 



, ' J- r J This material is manufactured by a number of 



Arsenate of J^ead . , . , , , , 



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 SO gaf. 



is sufficient, while for others S to 7 lbs. 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 SO 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. 



*Bulletiii 28, New York Agricultural Experiment Station. 



