New York Agricultural Experiment Station. 21D 



plum trees and in February to other varieties of fruit trees are 

 considered as sliowing that undiluted petroleum does not injure 

 fruit trees, although it may remain upon them for six mouihs; 

 also that it kills the scales when coming in contact with thorn 

 and that it has given the most promising results of any of the 

 insecticides that had come into use at that time. 



The experiments in this State by the State Entomologist, Ur. 

 E. P. Felt, furnished one of the first published records of results 

 with the insecticide in the north.^ A number of fruit and orna- 

 mental trees were included in these experiments. The former 

 consisted principally of wild cherry, peach, plum, pear, quince 

 and crab apple. Twenty and twenty-five per ct. emulsions of 

 crude petroleum and water were used as well as undiluted petro- 

 leum. All of the trees were sprayed in April. From these ex- 

 periments Dr. Felt concludes that " the trees appeared to be 

 uninjured by the insecticide* though possibly a little retarded, 

 while a large proportion of the scales are killed and on some 

 trees it would appear as though every one had been annihi- 

 lated; " also that the results with the 25 per ct. emulsion were 

 not enough better to warrant the use of the higher percentage 

 of oil and that owing to the serious injury to the trees treated 

 with the undiluted petroleum its use cannot be recommended. 



THE PRESENT STATUS OF CRUDE PETROLEUM AS AN INSECTICIDE. 



The above review, which includes the principal experiments 

 with crude petroleum yet published, brings out some points in 

 which the results as reported do not agree. It will be noticed 

 that Dr. Smith concludes that " straight " crude petroleum, of 

 the right character and specific gravity, if properly handled, is 

 harmless to the most tender varieties of fruit trees even when 

 applied undiluted, and that it may be depended upon to kill the 

 dormant scales when used undiluted or diluted with GO or 75 

 per ct. of water. 



While these experiments were supported in the main by those 

 of Prof. Corbett, the experiments by Dr. Felt, although agreeing 



^J<ew York State Museum Bui. 3G (Vol. 7). 

 'Refers to the 20 per ct. emulsion. 



