New Yoek Agricultural Experiment Station. 



323 



Summary. — Three different kinds of fruit trees and one variety 

 of currants were used in these experiments, including 15 pears, 

 17 plums, 1 crabapple and 2 currants, making a total of 35. In 

 all cases there was no injury to pears except where pure oil was 

 used in both Series I and II. Plums. were not injured by one 

 application at 40 per ct.; but seriously injured by two appli- 

 cations, and also by one application of 100 per ot. 



SPRAYING EXPERIMENTS TO DETERMINE THE PERCENTAGE OF KERO- 

 SENE OIL REQUIRED TO KILL THE SAN JOSE iJGALB WHILE 

 HIBERNATING. 



Seii£s I. — The trees were sprayed November 21. Weather 

 cloudy and windy, temperature 42°. During the following week 

 the weather varied from cloudy to clear with an average tem- 

 perature of 28°. 



Table V. — Percentage of Kerosene Required to Kill Hibernating 



Trees, 



Kind. 



Pear: 



Per- 



•— ^ cent- 



Ko. Age. age 



Trs. 



3 14 



San Jose Scale: Series I. 



oil. 

 20 



Bartlett, 41 10 20 



Bartlett, 4 10 



Degree of 

 infestation. 



Results. 



Badly infested; Scales appar 

 incrusted on ently not a£- 

 some parts. fected by the 



oil, May 31 and 



later. 



Checks. 



Scales but 

 little affected 

 by winter. 

 Larvae a- 

 bundant dur- 

 ing follow- 

 ing season. 



Majority o f No effect upon Same, 

 trees badly in- tbe scales, 

 fested, others 

 moderately. 



40 All badly infest- May 31. Scales Same, 

 ed; incrusted in dead; three 



places. 



Bartlett, 1 10 100 Well infested. 



trees not in- 

 jured; one tree 

 slight yellowing 

 of leaves. 



May 31. Scales Same, 

 dead. No injury 

 to tx*ee except 

 bark on lower 

 limbs and upper 

 part of trunk 

 slightly injured, 

 but not serious- 

 ly. 



