JOURNAL 



OF 



ECONOMIC ENTOMOLOGY 



OFFICIAL ORGAN AMERICAN ASSOCIATION OF ECONOMIC ENTOMOLOGISTS 



Vol. 12 OCTOBER, 1919 No. 5 



A DOSAGE SCHEDULE FOR CITRUS FUMIGATION WITH 

 LIQUID HYDROCYANIC ACID^ 



By R. S. WoGLUM, Bureau of Entomology, United States Department of Agriculture, 



Alhambra, Cat. 



The advent of liquid hydrocyanic acid into the field of fumigation 

 has brought about radical changes in appHcation and presented prob- 

 lems whose solutions appear necessary before the use of this recently 

 introduced material is placed on the stable basis required for effective 

 orchard treatment. In an effort to develop further information on 

 this subject the writer carried on, throughout the fumigation season 

 of 1918, extensive experiments, which included operations covering 

 several hundred acres of orange and lemon trees, both large and small, 

 infested with the black, purple or red scales. In this work liquid 

 hydrocyanic acid, 95 to 98 per cent pujre, was used, the application 

 being made in the form of a spray by special machines designed for 

 this purpose. Many parallel experiments with pot- and machine- 

 generated gas were performed. One outcome of this study has been 

 the accumulation of data showing that the dosage schedule originally 

 prepared for pot-generation of gas is not fully satisfactory' in its present 

 form for use with hquid hydrocyanic acid. This paper attempts to 

 show the comparative efficacy of liquid hydrocyanic acid and pot- 

 generated gas, and presents a new dosage schedule adapted to citrus 

 fumigation with liquid hydrocyanic acid, 95 to 98 per cent pure. 



>The writer wishes to acknowledge the a.ssistance given by Mr. ^^. H. Rounds who 

 performed an active part in much of tlie experimental work on which this paper is 

 based . 



This paper was not received in time for inclusion in the Proceedings of the Pacific 

 Slope Meeting, publishcil in tiu> ()ctol)cr issue. [Kd.] 



