154 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 14 



FUMIGATION WITH HYDROGEN CYANIDE FOR THE CONTROL 

 OF THE PEAR PSYLLA 



By R. L. Webster, Ithaca, N. Y. 

 (Paper withdrawn for publication elsewhere) 



Mr. H. a. Gossard : I would like to know if fumigation is a possible 

 method for eradication in small areas ? We have, so far as I know, only 

 one center of psylla infestation in the state of Ohio, and this is very small 

 "With sufficient equipment, the work might be done in, say one night. 



Would there be any possibility of exterminating the psylla by this 

 method ? 



Mr. R. L. Webster: I think you can very nearly do that. In the 

 first orchard I fumigated in the spring of 1919, the psylla has not come 

 back to be of any importance. That has not been true of other orchards, 

 however, where there has been reinfestation from the outside. In one 

 case there was considerable infestation from the timber adjacent. In 

 some experiments which Professor Parrott made about three years ago, 

 the psylla has not come back in sufficient numbers to require further 

 treatment. 



Mr. H. a. Gossard : I would like to ask if any one can report on the 

 success that the California people have had from using balloons for the 

 purpose of dropping these tents over large trees ? 



Mr. E. R. Sasscer: While on my way to California last spring, my 

 attention was drawn to an article in, I think. Popular Science Monthly, 

 to the effect that balloons were to be employed in placing tents over 

 trees for fvimigation. On my arrival in Alhambra, I asked Mr. Woglum 

 if balloons were being used for the purpose stated, and he replied that 

 some one had suggested their use, but so far as he knows, little progress 

 has been made. It is safe to say that they are not at the present time 

 being used in commercial groves. 



President Wilmon Newell: The next paper is by Alvah Peterson. 



SOME EXPERIMENTS WITH PARADICHLOROBENZENE AND 



OTHER CHEMICALS FOR THE CONTROL OF THE PEACH TREE 



BORER, SAXXiyOIDEA EXITIOSA SAY 



By Alvah Peterson, New Brunswick, N. J. 



(Withdrawn for publication elsewhere) 



Mr. George A. Dean: At what maximimi depth were the larvae 

 killed? 



