250 Report op the Department of Extomodogy of the 



with the Virginia results in that the 20 per ct. mixture kiUcd 

 the scales, gave very different results with undiluted petroleum. 

 In this case, although the petroleum was of the required char- 

 acter, testing 43°, it seriously injured or killed all the trees to 

 which it was applied. 



From the above review and summary it ai)pears that the exact 

 effect of crude petroleum of the proper standard upon both 

 scales and trees is not yet fully determined; hence further 

 investigation is desirable. 



objects of the experiments. 



The experiments with crude petroleum reported in this bul- 

 letin were undertaken principally with a view to adding further 

 data as to its effect upon both scales and trees. Conflicting 

 results with this insecticide in the hands of Western New York 

 orchardists have also made a series of experiments in this sec- 

 tion of the State desirable. 



C0:>JDITI0N AND CLASSIFICATION. 



The experiments were conducted in a number of different 

 orchards, all of them in western New York. In each case .the 

 condition of the trees was carefully noted. 



The crude petroleum used was purchased of the Standard Oil 

 Company. It was dark green in color and had a specific gravity 

 of 44°. 



An emulsifying pump of the type that emulsifies the oil and 

 water at the nozzles was used in all of the experiments. The 

 spray was very fine and the emulsion thus made was excellent, 

 the oil being so thoroughly broken up that it did not wholly 

 separate from the water in the 1,000 cc. graduate in which the 

 tests were made for over two days. 



To avoid error in the amount of oil applied the pump was 

 frequently tested. These tests showed only very slight varia- 

 tions in the percentages. 



Much pains was also taken to make the applications thorough 

 and uniform. The spray was directed upon the tree until it 



