Notes on Effects of Kerosene. 171 



the foliage and branches are merely moistened. In the latter case 

 the evaporation is rapid, and this seems to be one of the essential 

 features in avoiding the injurious effects of kerosene. 



The results of our experience in the use of kerosene are not 

 unlike those of others. Experimenters have recorded very con- 

 flicting results in their experience with pure oil, in some 

 instances very little harm coming from its use, while in other 

 and similar cases, without apparent cause or reason, very serious 

 results have occurred. 



Why such conflicting results should occur is difiicult to 

 explain, but it seems not unlikely that it may be due to the 

 individual variation of the trees or plants treated. 



From our study of the subject we draw the following 



Summary. 



1. Pure kerosene is likely to seriously injure peach trees even 

 when they are perfectly dormant. 



2. A 20 per cent mixture of kerosene can probably be safely 

 used on the peach at any time, but a stronger mixture cannot 

 always be so applied. 



3. Apple trees do not appear to be as susceptible to the action 

 of kerosene as peaches. In some instances clear kerosene did not 

 harm them. 



4. There seems to be little, if any danger, to apple trees from 

 a mixture containing 50 per cent or less of kerosene. 



5. Very conflicting results are often obtained from the use of 

 kerosene. 



6. Kerosene is especially likely to cause injury if applied on 

 other than a bright sunny day. 



7. In our experience, a 20 per cent solution (i part oil to 4 

 parts water) is harmless to plants and destructive to insects, even 

 to the San Jose scale. H. P. Gould. 



