95 



KEROSENE. 



The first essays with pure kerosene against scale insects were con- 

 ducted in the winter of 1893-94:, when a number of peach trees on the 

 grounds of the U. S. Department of Agriculture infested with the new 

 peach scale, Diaspis lanatus, were treated with the undiluted oil as one 

 of a series of experiments with var ; ous substances against this insect. 

 Applications were made during January and February and later, early 

 in March. The results were very successful so far as the test with 

 pure kerosene was concerned, the scales having been killed and the 

 trees remaining uninjured, blooming abundantly the following spring, 

 and showing no damage later. As this scale is confined to the trunk 

 aud larger limbs of the trees, the application of oil was not general, 

 but was limited to the parts named, and deductions could not, there- 

 fore, be drawn as to the effect of the treatment of trees in toto. A 

 resume of the results was presented in August, 1894, at the sixth 

 annual meeting of this association. 1 



In the active experimental work undertaken against the San Jose 

 scale during the following winter (1894-95) the results with pure kero- 

 sene against the peach Diaspis were considered of sufficient significance 

 to lead to the repetition of the tests on San Jose scale infested peach 

 trees at Eiverside, Md., and in January, 1895, applications of pure coal 

 oil were made to two trees, one badly incrusted with scale, and the 

 other very slightly infested. The scales in this instance were all killed, 

 as had been the case with the Diaspis, but the trees unfortunately tailed 

 to survive the treatment. 2 



The outcome of this preliminary experiment with kerosene against the 

 San Jose scale, while demonstrating that the pure oil will kill the scales 

 perhaps more effectively than any other application known, and at very 

 slight cost, was yet accompanied with such disastrous results to the 

 plants themselves that further tests were not made until the subject 

 was again given prominence by the report, in discussion of the use of 

 pure oil, in Ohio, by Mr. Webster, at the eighth annual meeting of this 

 association, in 1896. 3 



Following up this new suggestion of the possible value of undiluted 

 kerosene as a means of controlling the San Jose scale, a series of tests 

 were made during the winter of 1896-97, and reported last year at the 

 ninth annual meeting of this association. 



The outcome of these experiments seems to contradict the earlier 

 tests, although the latter were carefully conducted, and much more 

 so undoubtedly than would be the case in normal orchard work. 



As noted in the paper cited, the experiments of the winter of 1896-97 

 were not followed by any real or permanent injury to any of the trees 



i Insect Life, Vol. VII, pp. 118 and 119. 



2 Insect Life, Vol. VII, pp. 365-374. 



3 Bull. No. 6, n. s., Div. Ent., Dept. Agric, p. 42. 



