318 Report of the Department of Entomology op the 



reliable results. The treating of a large number of trees was 

 purposely avoided in order to give an oppor-tunitj of making the 

 treatment thorough and accurate. 



OBJECTS OP the experiments. 



The principal objects of these experiments were: To determine 

 the effects of winter applications of kerosene oil (1) on healthy 

 nursery trees and (2) on healthy bearing trees; (3) to determine 

 the percentage of oil required to kill the scale during the winter; 

 and (4) to determine the effects of summer applications upon 

 healthy bearing trees. 



conditions. 



Unless otherwise stated only 150° fire test oil was used. In 

 all cases the oil was applied in the form of a spray, the machine 

 being frequently tested to ascertain whether the right propor- 

 tions of oil and water were being maintained. Much care was 

 also taken to make the applications even, each tree being wet to 

 the same degree. 



EXPERIMENTS TO DETEPtMINE THE EFFECTS OP WINTER APPLICATIONS 

 OP KEROSENE OIL ON HEALTHY NURSERY TREES. 



These experiments were divided into two series, the first receiv- 

 ing one application and the second two applications.^ 



Series I. — Sprayed November 22; temperature 49°, high wind, 

 cloudy. Weather during the week following alternately cloudy 

 and bright, with average temperature of 27°. 



'Unless otherwise stated, the trees in Series I and II liave received one 

 and two applications of oil, respectively. 



