JOURNAL 



OF 



ECONOMIC ENTOMOLOGY 



OFFICIAL ORGAN AMERICAN ASSOCIATION OF ECONOMIC ENTOMOLOGISTS 



Vol. 6 APRIL, 1913 No. 2 



Proceedings of the T\venty-fifth Annual Meeting 



of the American Association of Economic 



Entomologists 



{Continued from page 112) 



President W. D. Hunter: The next paper will be by Mr. W. J. 

 Schoene on "Notes on Comparative Tests with Zinc Arsenite and 

 Arsenate of Lead." 



NOTES ON COMPARATIVE TESTS WITH ZINC ARSENITE 

 AND ARSENATE OF LEAD 



By W. J. Schoene 



The statement has been made that in proportion to its arsenical 

 content zinc arsenite is more toxic to insects than arsenate of lead. 

 In order to determine this point feeding tests were arranged to secure 

 more data regarding the comparative efficiency of these poisons. At 

 the same time experiments were made to determine the effect of zinc 

 arsenite on foliage. 



Most of the feeding tests were made in the laboratory, the foliage 

 being usually sprayed with an aspirator. Sometimes leaves were 

 .taken from especially treated trees in the field. Arsenate of lead and 

 zinc arsenite were used singly and in combination with bordeaux, 

 lime-sulphur, molasses, glucose, soap, glue and lime. One sample 

 of lead arsenate paste was taken as a standard for comparison and the 

 poisons were used at the rate of 3 pounds of lead or 1 pound of zinc 

 to 50 gallons of spray. The lead contained 17.75 per cent arsenic 

 oxide and the zinc 40.28 per cent arsenious oxide. To ascertain its 

 safeness to fohage zinc arsenite was applied to apple, pear, peach, 

 elm, willow, cabbage and potato. The insects employed in the feeding 

 tests were the spiny-elm caterpillar {Euvanessa antiopa L.), fall web- 



