lyo Bulletin 155. 



to use it with impunity that a series of experiments was 

 begun during the winter of 1897-8. Tlie trees used for this 

 work were young peaches and apples. 



Kerosene in four strengths was used ; pure, 50, 40 and 20 per 

 cent. 



The first series of trees was sprayed February 7, and others 

 March 7, April 13, May 3 ; and the final notes were made 

 May 20 and July 8. The character of the weather was 

 carefully noted at each treatment. In applying the kerosene to 

 the trees, a Stott's nozzle, which makesa very fine spray, was used, 

 and while the trees were thoroughly sprayed, care was taken not 

 to apply more of the various strengths of kerosene than was 

 required to thoroughly moisten the surfaces. 



It is not necessary to repeat all the details of the experiment, 

 but to give only the summary conclusions. 



From the results of the experiment, it was evident that kero- 

 sene should be used with caution, especially on peach trees. 

 While in no case were any apple trees greatly injured, several 

 peaches suffered very serious injury. Any mixture of kerosene 

 stronger than 20 per cent, applied to peach trees, even when 

 dormant, is likely to affect the tree injuriously. In some cases 

 under observation, it was noted that a 50 per cent mixture was 

 more disastrous than when used undiluted. 



It seems probable that clear keiosene may be used on apple 

 trees without serious results, although it is not unlikely that 

 trees so treated are in some instances more or less weakened. 

 Any strengths weaker than 50 per cent seem to have little, if any, 

 injurious effect on apple trees. 



Again, in the light of the data at hand, the commonly accepted 

 notion that kerosene applied on a cloudy day is more likely to 

 injure the plant than if applied on a clear sunshin}^ day, is 

 corrobrated. With only one exception in the case at hand, did 

 this result otherwise. 



It is not unlikely that the manner in which the kerosene is 

 applied may have material effect upon the results. If the spray 

 is coarse, so that in applying it the trees become drenched with 

 oil and it forms in drops on the tips of the leaves, the danger is 

 doubtless much greater than when a very fine spray is used and 



