STATE rOMOLOGICAL SOCIETY. "J^ 



plete solutions are mixed, arsenate of lead is formed as a curdy, 

 white precipitate. The receptacles should be wooden, as the 

 chemicals act upon metal. The total weights of ingredients will 

 give about one-half that weight of arsenate of lead. Thus, if 

 eleven pounds sugar of lead and four pounds arsenate of soda 

 are used, the resulting amount of arsenate of lead will be seven 

 and one-half pounds, a quantity of poison sufficient for 400-500 

 gallons of water. 



The cost of arsenate of lead thus prepared is somewhat greater 

 than that of Paris green, but since when thoroughly applied no 

 respraving is necessary, in the course of the season the actual 

 expense generally will be less than when Paris green is used. 

 In all cases one may use arsenate of lead, properly prepared, 

 without fear of injury to foliage. I might add in passing that 

 the itse of arsenate of lead as an insecticide was first proposed 

 by a native of this State. ]\Ir. F. C. Aloulton. a former cheinist 

 to our gypsy moth committee. 



Contact insecticides are used generally against plant lice and 

 scales. As these insects do not take solid food but depend for 

 nourishment upon plant juices which they obtain by means of 

 their slender beaks, they are not susceptible to the remedies used 

 against leaf-eaters : hence, in these cases we make use of oily or 

 soapy washes that close the breathing pores of the insects. 



The contact insecticides most generally used are kerosene 

 emulsion and whale oil soap. Kerosene emulsion is made by 

 dissolving one-fourth pound hard soap, cut fine, in two quarts 

 of hot water and adding to the soap suds while still hot. one 

 gallon kerosene oil. The whole mixture is churned or stirred 

 until cool, when a thick, white emulsion is formed. This emul- 

 sion can be kept indefinitely and for use on plants should be 

 diluted at the rate of one part to nine of water. Whale oil soap 

 is a heavy, dark colored soap, made from fish oil and is used for 

 the same purpose as kerosene emulsion. It also has an especial 

 importance as a means of treating the San Jose scale, a matter 

 to be referred to later. 



