43 



lent opportunit}" was thus ati'orded for testinof the influence of the 

 weatlier upon the effect of the oil sprays. Applications were made 

 on fair and cloiid}^ daj'S, immediately before and after rains, early 

 mornings, and late afternoons. Peculiarly enough, however, the dif- 

 ferent conditions attending* the various applications made no apparent 

 difference in the effect of the oil upon the trees or scale insects; like- 

 wise no appreciable difference in the results could be detected between 

 early and late applications. This was rather surprising, as it was 

 expected that applications followed within a few hours bv clouds and 

 rain would result in damage to the treated trees. 



No attempt is made to record the details of these experiments here. 

 Below some of the tests are summarized in a general way. Applica- 

 tions having been made at different seasons and under different 

 weather conditions, a large number of plots were required and many 

 of these could not be included in the tables. 



Crude ])etroleuin. — A summary of the applications and results in the 

 Frederick orchard is given in Table I. It is not deemed necessary to 

 give a similar table of the work in the Rumph orchard which, though 

 on a much more extensive scale, does not give results materially 

 different from those contained in this table. It is worthy of note, 

 however, that the trees in the Humph orchard received no apparent 

 damage from any strength of oil applied, while some injury was noted 

 in the Frederick orchard, attributable in part to defects in the pump 

 and possibly to some extent to the condition of the trees, the Rumph 

 orchard not having yet come into full bearing. 



