Factors affecting efficiency in fumigation with hydrocyanic acid

Abstract does not appear. First page follows.

Introduction

In most of the previous efforts to determine gas concentration, rate of diffusion, leakage, etc., in fumigation with hydrocyanic acid the results have been expressed in terms of insect kill. This method is not entirely adequate inasmuch as it fails to provide any data as to the actual concentration of gas present under the tent at any given time during the exposure, the rate of leakage through the tent, or the effect of temperature.

In an effort to gain a more complete understanding of what actually occurs during fumigation the writer has attacked the problem from both the chemical and the entomological standpoint, with the following aims: (1) To ascertain the actual gas concentration necessary to kill coccinellid beetles (Hippodamia convergens Guer.) and red scale (Chrysomphalus aurantii Mask.); (2) to establish a standard of measurement by which the relative efficiency of different methods of fumigation might be determined; and (3) to apply the results thus obtained to the study of certain factors affecting killing efficiency under the conditions of orchard fumigation.