1896.] ENTOMOLOGICAL NEWS. 269 



DEPARTMENT OF EGONOMIG ENTOMOLOGY. 



Edited by Prof. JOHN B. SMITH, ScD., New Brunswick, N. J. 



Papers for this department are solicited. They should be sent to the editor. Prof. John 

 B. Smith, Sc.D., New Brunswick, N.J. 



(Continued from page 217.) 



Proceedings of the Association of Economic Entomologists.— Mr. A. H. 



Kirkland gave some " Notes Concerning Insecticide Experiments." He 

 spoke particularly of arsenate of barium, with which they had experi- 

 mented in Massachusetts for the first time this year, and m his opinion it 

 is the best arsenical compound that has been yet used against the Gypsy 

 moth. Some remarks were made upon this insect and the chemical and 

 other tests upon the nature of its digestive secretions, the obj'ect being to 

 ascertain, if possible, why arsenite in the ordinary forms exercised so 

 feeble an eflfect upon this insect. It was from the information thus ob- 

 tained that the arsenate of barium was tried, and it seems to have been 

 successful. The substance is not yet in shape for recommendation in 

 ordinary use, and the method of preparing it is somewhat complicated. 



Afternoon Session. — Mr. C. L. Marlatt spoke of " Comparative Tests 

 with new and old Arsenicals on Foliage and Larvae." As illustrating the 

 importance of the matter Mr. Marlatt stated that at the present time 2000 

 tons of Paris green per year were sold for insecticide purposes ! He de- 

 tailed a series of experiments with Scheeles' green, the plain arsenate of 

 copper, Paris or Schweinefurth's green, or aceto-arsenite of copper, with 

 London purple, with arsenate of lead and with arsenite of lead. The 

 effect of the addition of lime to these materials was discussed and was 

 generally found to be beneficial. Mr. Marlatt seems to favor the arseniie 

 of lead, a preparation not heretofore used as against insects and not 

 commercially manufactured on a large scale. He also urges the use of 

 the simple arsenite of copper or Scheeles' green in place of the ordi- 

 nary Paris green. It contains quite as much arsenic, but is very much 

 more finely divided, remains in suspension much better, can be more 

 completely distributed, and is more rapidly effective. Further, it is very 

 decidedly cheaper, and this is a matter of very considerable importance 

 to the farmer. Mr. Marlatt further suggested that it was not always pos- 

 sible to judge of injury caused by the arsenites immediately after their 

 apphcation. In some cases no immediate eflfect was perceptible, Jind it 

 was not until days or weeks afterward that evidence of the action of the 

 poison upon the leaves became obvious. It usually resulted in a prema- 

 ture maturing on ripening of the foliage. This paper was discussed by a 

 number of the members, principally in the direction of questioning Mr. 

 Marlatt and in recounting experiences bearing out or contradicting his 

 statements. The most interesting point was the assertion by Messrs. 

 Kirkland and Forbush, that the addition of lime rather increased injury 

 to foliage in their experiments, and certainly did not prevtnt it as com- 



