FIFTEENTH ANNUAL MEETING. 69 



San lose scale at Cornell and what are you goinj^ to do about 

 it? \\'e are g'oing- to spray, and we are goinc: to use one of 

 these soluble oils, and we are going to do it in the spring. 

 If I was only going to do it once. I would wait until ]\larch. 



Prof. Gulley : Is it possible to use the oils and then revert 

 again to the lime and sulphur ? 



Prof. Slingeri^nd: I don't know; that is a very serious 

 condition. If you put on the oil first and then put on the 

 lime and sulphur, I am afraid the latter would not stick as 

 well ; I don't think I would use that combination. 



A Member : How would it do to use the lime and sulphur 

 and then follow with the oil in the spring? 



Prof. Slingerland: I think that would be a better com- 

 bination. 



A Member: I would like to ask about these oils, as to 

 whether they show as well on the tree when applied as the lime 

 and sulphur? 



Prof. Slingerland: No; they do not as well as the lime- 

 sulphur sprays, though they do make the tree look oily. I 

 would spray the tree until the oil runs down pretty well; give 

 it a good drenching. 



A Member: Why wouldn't it do to mix a little lime in? 



Prof. Slingerland: I don't know whether you can put lime 

 in these oils. We have got to learn a good deal about these 

 oils ; they are simply in the experimental stage. 



A Member: I have used Reynolds' Paris green, but I don't 

 think it is pure, although they claim it is. 



Prof. Slingerland: I suppose our New York Paris green 

 is made by the same manufacturers you get it from, but I am 

 afraid the manufacturers sell very good Paris green in New 

 York and bad in the other states. I had a letter from a man- 

 ufacturer wdiich set me to thinking on this line. One of our 

 assistants was going to use several pounds of arsenate of 

 lead, and he wrote to the manufacturer asking him how much 

 free arsenic there w^as in it. Now free arsenic burns the foliage, 

 and the manufacturer replied, we try to make our arsenate of 

 lead so there is not more than four per cent, of free arsenic 

 in it. Now our New York state law says that all poison 

 insecticide shall not have more than 3>^ per cent of arsenic in 



