36 Second Annual Report 



mont the kerosene-limoid emulsion should prove particularly 

 effective against the oyster shell-bark louse and the aphides. 



Arsenites are employed in combating the codling moth. 

 These are usually applied in connection with the Bordeaux 

 shortly after the blossoms have fallen. Success in combat- 

 ing the codling moth depends very largely, if not wholly, upon 

 the purity of the arsenical poison used, and the ability of the 

 operator to apply the spray so thoroughly that the calyx end 

 of every fruit shall receive some of the poison. It is needless 

 to say that spraying for the codling moth must be done after 

 the fruit has set and before it has begun to turn downward. 

 Generally speaking, the trade paris green of today is variable 

 in its arsenical content,, and is not considered as reliable an 

 insecticide as some of the newer preparations now being man- 

 ufactured. In the writer's judgment the arsenate and arsenite 

 of lead are the best arsenical poisons now in the trade. The 

 arsenate of lead, which is considered the best, is formed by 

 combining lead acetate and arsenate of soda. Various prepara- 

 tions of these substances are now on the market and are known 

 to the trade as Disparene, "Pink" and "White Arsenoid," etc. 

 The prepared forms are considerably more expensive than the 

 raw materials which are its essential insecticidal components. 



Station trials of arsenites during the past season. — The 

 horticultural department wishing to give the arsenate of lead 

 a thorough trial ordered a supply of lead acetate and arsenate 

 of soda from one of the leading New York chemical supply 

 houses, and in due time received packages supposedly contain- 

 ing what had been ordered, the accompanying bill being made 

 out according to the order' sent in. On opening the boxes it 

 was found that the arsenate of soda was labelled arsenite of 

 soda. Inquiry of the firm elicited the information that only 

 one commercial article was carried, which was a mixture of 

 arsenate and arsenite. and that it went under the name of arsen- 

 ate or arsenite of soda and was always given when either of the 

 two were ordered. The reply also conveyed the information 

 that true arsenate of soda was only handled by the firm as 

 a pure articlq. put up in one and five pound bottles at cost of 

 thirty cents per pound, as against nine cents for the technical 

 mixed article. If this illustration is an example of the trade 

 in general, then it is questionable if there is any genuine com- 

 mercial arsenate or arsenite of soda, and arsenate or arsen- 

 ite of lead spray mixtures. At any rate the indications are that 

 in some cases at least it is open to question. In making up 

 fifty gallons of the arsenical solution, 21 ounces of lead acetate 

 and 4 ounces of arsenite of soda (?) were used. The lead 



