i':\ri':KiMi:N IS anp ()i5si':k\ a iions on riii': 



USl': Ol' CKini'. PKTROLia'M AND 



PURE Kl.ROSI'M'. lOR \\\\i 



SAN JOSl'. SCAl.h. 



At C\\k riiKxii.i.i-:, li.i.. 



For the purpose of contributing- to a knowledg-e of the val- 

 ues of these insecticides, anvl also as a basis for recommenda- 

 tions to Illinois fruit gTOwers, I provided early in l'H)2 for a 

 small series of careful experiments to be made at Carterville, on 

 trees infested by the San Jose scale. The insecticide sprays 

 were applied March \2 and 15 by the field entomologist of the 

 office, Mr. E. S. G. Titus, and the results were tested by in- 

 spections made by him April 29 and Juno Iv'^ of the same year. 

 It was a part of my object to show the best that these insecticides 

 could do under ordinarily favorable conditions, and I consequently 

 chose for the experiment a time commonly regarded as most favor- 

 able to their use, that during which ilanger of injury to the most 

 sensitive kinds of trees is at a minimum. The fruit-buds of all the 

 trees treated were much swollen at the date of the experiment in 

 southern Illinois, but neither these nor the leaf buds had as yet 

 beg"un to open. 



The materials used were crude petroleum (an Ohio oil of Mtyj"^ 

 specidc gravity by the Ueaumc test) and common kerosene bought 

 from the Standard Oil Company and flashing at 14.^^' to 145' . A 

 Morrill iV Morley pump was used in the experiment, with a heavy 

 -'^s-inch hose, a 12-foot bamboo rod^ and a Caswell nozxle. The 

 spraying was very carefully done under the immediate supervision 

 of Mr. Titus, and the smallest possible amount of the oils was used 

 that would thoroughly coat the tree. On one peach- and one pear- 

 tree, however, a heavy but very fine spray was applied. None of 

 the trees were sprayed sufficiently to cause them to drip. 



The weather of the time was fair and sunn}' throughout. 



Fifty-two trees were sprayed in all thirty-one with kerosene 

 and twenty-one with crude oil. They were in two orchards, one 



01 



