April, ’20] 
PETERSON: PEACH-TREE BORER 
207 
The granular or dry sodium cyanide is just as efficient as the liquid 
(one ounce to one gallon of water) and much easier to apply. One 
half ounce and in many cases three fourths ounce treatments for five- 
to ten-year-old trees will not kill a sufficient number of larvae to 
constitute a practical control. 
Vigorously growing peach trees five to ten years of age have not been 
injured by one ounce treatments when the applications were made in 
May, June, September, or October. Also healthy trees two to four 
years of age have not been injured by one half ounce treatments. 
Acknowledgments 
I am indebted to Mr. C. H. Connors and Mr. M. A. Blake for 
valuable information concerning their results with sodium cyanide. 
I wish to thank Dr. T. J. Headlee for many important suggestions 
received. I am also indebted to a number of peach tree growers in 
New Jersey who have permitted me to carry on investigations in their 
orchards. 
Mr. 0. I. Snapp: I would like to ask Mr. Peterson how close to 
the tree trunk the material was placed? 
Mr. Alvah Peterson: In the liquid treatments, a trough was 
dug about the tree two to four inches deep; the liquid was poured 
into the trough so that it came in contact with the tree. In the dry 
treatment fine, granular sodium cyanide was used. This was sprinkled 
in the trough about the tree. The majority of the sodium cyanide 
would be an inch or two away from the tree. 
Mr. G. G. Becker: In order to get a little more definitely at the 
direct state of application, I would like Mr. Peterson to tell us about 
the time of emergence of the moth in New Jersey, and whether the 
applications were used then or not. 
Mr. Alvah Peterson: For three seasons we have been studying 
the peach-tree borer; the first year was devoted largely to a life his¬ 
tory study in New Jersey and also a preliminary study of various 
methods of control. We find that the majority of adults emerge in 
August. They start to come out about June 15 and some may be 
found as late as September 15th, but the greatest number come out 
the first two weeks in August. I have found eggs on the trees as 
late as September 20th. 
We made applications in May, June, September, October and 
November. I am of the opinion that in using a toxic gas for killing 
the peach-tree borer, it would be advisable to make the application 
late in September or early in October. I would not put it off too late 
in the season due to the fact that the soil becomes cold and the larvae 
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