UNITED STATES DEPARTMENT OF AGRICULTURE 

 BULLETIN No. 907 



Contribution from the Bureau of Entomology 

 L. O. HOWARD, Chief 



Washington, D. C. PROFESSIONAL PAPER October 20, 1920 



FUMIGATION OF CITRUS PLANTS WITH 



HYDROCYANIC ACID: 



CONDITIONS INFLUENCING INJURY 



By 



R. S. WOGLUM, Entomologist, Tropical and Subtropical 

 Fruit Insect Investigations 



CONTENTS 



Introduction 1 



The Effect of Hydrocyanic Acid on Plants 2 



Details of Experiments 3 



The Effect on Plant Injury of Temperature, Light, and Moisture before Fumigation . 4 



The Effect on Plant Injury of Temperature, Light, and Moisture after Fumigation . 10 



The Effect on Plant Injury of Temperature, Light, and Moisture during Fumigation . 22 



General Discussion of Factors which Influence Fumigation Injury . . . . 27 



The Concentration of the Gas ...28 



The Length of Exposure . . .. . . 29 



The Physiological Condition of the Plant 30 



Atmospheric and Light Conditions '. . . 33 



Summary 41 



Literature Cited ' 42 



WASHINGTON 

 GOVERNMENT PRINTING OFFICE 



1920 



