190 



JOURNAL OF ECONOAIIC ENTOMOLOGY 



\yo\. 8 



conducted primarily to ascertain whether the 6 per cent emulsion would 

 kill the greatest part of the aphids, and to determine the effect of the 

 insectide on the vegetative state of the tree. Ample infested checks 

 were retained. 



Examination July, 1914, showed that while onl}^ two trees were en- 

 tirely free from aphis, the balance with the exception of two trees were 

 free from aphis where the spray influence must have been greatest, 

 I. e., near the crow^n. The other trees showed one or two isolated clus- 

 ters of aphids far out from the base of the trees. 



The application was repeated two days after the above examina- 

 tion and in addition eight other trees in this block were similarly 

 treated, leaving two trees as checks. 



In addition to the effect on the aphids, a most excellent effect on- 

 the vegetative state of the trees was apparent. New roots were- 

 very num^erous and the old bark was replaced by new tissue. Appar- 

 entty, the spray was just sufficient^ injurious to the tissues to stimu-^ 

 late the tree to grow new^ roots and bark. 



Kerosene Emulsion 



Nine trees were sprayed July 6, 1912, with 4 gallons each of 10 per 

 cent kerosene emulsion. The earth was removed and not replaced 

 until July 8 owing to threatening showers, which however did not 

 materialize. These trees were all infested. Examination Julj^, 1913, 

 showed every tree badh^ injured by the kerosene. The small roots 

 were dead and partially decayed and the outside bark around the 

 crowns entirely killed. 



Summary 



1. Of all the insecticides used Electro Pine Tar Creosote holds the 

 greatest promise due to, first, its power to kill the aphids; second, its 

 strong repellant action and its retention of the penetrating odor after 

 at least twenty-one months in the soil; third, its stimulative effect on 

 diseased tissues, and fourth, the possibility of emulsifying it readily. 



2. There is a symbiotic relationship between the aphids and Lasius 

 {Acantliomyo'ps) inter jectus Mayr. 



There appears to be a congregating habit in L. interjedus Mayr., of 

 which it may be possible to take advantage in controlling the ant. 

 Creosote is an effective repellant for this ant. 



3. Paradise stocks show some degree of immunity to attack bv the 

 root forms of the woolly aphis. 



President H. T. Fernald: The next paper on the program will, 

 be read by W. C. O'Kane. 



