26 



iug to notes made up to June 12. Until that date the sprayed trees 

 remained oil}' and the odor of the crude petroleum could j^et be 

 detected. It is a reasonable conclusion, then, that the scale can not 

 live so long under such a coating of oil. He had concluded that the 

 25 per cent crude petroleum in mechanical mixture was better than 

 refined kerosene of the same strength. 



Mr. Woodworth said that when the bulletin from the New Jersey 

 Station came out it was heralded all over California, and he had to 

 write more letters in regard to the kerosene and crude-petroleum treat- 

 ment than about any other insecticide. Crude petroleum in California 

 is a very indefinite term, since there is a crude petroleum from Ven- 

 tura which is as thick and black as molasses, and from that it varies 

 to crude petroleum which is almost as thin as gasoline. Even in a 

 single well the product varies according to depth and age, and distilla- 

 tions show that it varies greatly in composition. He had been assured 

 that the Eastern product varied also, and was of opinion that before w^e 

 can recommend any percentages of crude petroleum we will have to 

 establish a criterion of excellence. The different kinds of crude 

 petroleum he had experimented with in California produced very dif- 

 ferent results — strikingh" difierent. There is also a very decided dif- 

 ference in results according to time of spraying with the same oil. 

 Thus spraying before rain and after rain may produce entirely different 

 results. He had sprayed with some forms of crude petroleum without 

 injury which would have thoroughly destroyed the foliage at another 

 time of day. The amount of water in the leaf may determine to a 

 certain extent the damage by the oil. It seemed to him, therefore, that 

 another thing that must be done before we can really properly under- 

 stand the action of the oil will be to study the effect of the oil upon 

 the vegetable tissue. Perhaps this had already been done, but it was 

 still in large part a mystery to him. 



Mr. Webster said he had used oil from two wells located in differ- 

 ent parts of Ohio this year, and although the analysis ran almost 

 exactly the same in each case the effect has been different. In the one 

 case he had not seen the orchard for several weeks, but when he last 

 saw it the peach trees seemed to have been in many instances killed 

 b}'^ the use of crude petroleum. He could not say whether the oil had 

 been applied just before or just after a rain. In the other case the 

 trees sprayed were seedling apples on the experiment farm, the experi- 

 ment being made to determine if possible the effect upon the trees and 

 not against insects. Some of the trees leaved out at the proper time 

 about as freely as usual, while others had no leaves at all. At the 

 present time, however, there was no apparent difference whatever in 

 them, all having finally leaved out precisely the same. It was evi- 

 dently nothing l)ut a tcnnporary injury. His experiments had pro- 

 duced such varied results that he was biidly mixed up and did not favor 



