96 



treated, and the tests extended to young peach trees and old trees, and 

 also young apple, pear, cherry, and quince trees, and several ornamental 

 shrubs. 



In the meantime the experiments of others had given a variety of 

 results, in some cases the plants being killed or much injured, in others 

 no deleterious results following the treatment. 



Our conclusions, as expressed at the time, were that spraying with 

 pure oil will often kill trees, and that kerosene as an insecticide is to be 

 used with caution and with the full appreciation of the fact that the 

 death of the plant may result. 



In the winter of 1897-98 the tests made with young trees of the 

 previous winter were repeated, the applications being made under 

 different weather conditions; in some instances during cloudy or 

 moist weather, and in others on bright, warm, and dry days. The 

 results duplicated in the main those of the previous year, with the 

 exception of certain peach trees, included in one of the first tests, 

 which were killed to the ground. Peach trees subjected to treatment 

 later were uninjured. The trees killed were sprayed on a still day, with 

 a very moist atmosphere, the sun occasionally breaking through the 

 light fog, and it was noticed that the kerosene remained in evidence on 

 the trees for some time; it seemed in fact to have soaked into the bark 

 during the moist period, and in the bright weather following was not 

 readily given up. Apple, pear, cherry, and quince trees, however, 

 treated at the same time developed no appreciable injury. 



The tests, therefore, up to the present time made with this oil indicate 

 that it may often be used with little if any danger to the plant and 

 with perfectly satisfactory results so far as killing scale insects is con- 

 cerned, but that the peach tree under unfavorable weather conditions, 

 or such as lead to the slow evaporation (and these conditions are not 

 always easily recognizable), is very apt to be killed or badly damaged, 

 and that corresponding damage to other trees is possible, though less 

 likely to result. The general ground taken in 1897, therefore, is 

 adhered to, namely, that the treatment with oil is dangerous and 

 may kill the trees, and its use should never be recommended without 

 calling attention to this possibility, leaving the grower to determine 

 for himself whether he wishes to take the risk or not. 



FISH-OIL SOAPS. 



The writer has made reports on these soaps at various times, more 

 particularly detailing the results of experiments undertaken to deter- 

 mine the characteristics of the best soap for insecticide purposes, and 

 to detect the deleterious substances or qualities which render many of 

 these soaps unfit for use. The determination of the water constituent 

 of soap, and of the bearing of the latter on the value of the article for 

 insecticide purposes, was one of the first things investigated, and it 

 was demonstrated in the report before the seventh and eighth annual 



