The Use of Carbon Dioxide Production as a Measure of Infestation of Grain by Insects

Abstract

1. A detailed technique is described for the routine determination of the carbon dioxide output of samples of grain. The concentration of carbon dioxide produced in the intergranular air during incubation for 24 hours at 25°C. is known as the “carbon dioxide figure” of the sample. 2. Suggestions for relating the carbon dioxide figure to potentialities for future storage are given. A high carbon dioxide figure indicates that the grain is unsuitable for storage. 3. The carbon dioxide figure is largely a measure of insect infestation of the sample and a table is given by which the numbers of various species of insects common in grain may be estimated from the carbon dioxide figure. 4. Theoretical considerations affecting the carbon dioxide figure are discussed as far as available knowledge permits. 5. Data obtained in the laboratory during development of the method are presented, and show it to give a useful measure of the amount of infestation. This work forms part of the programme of the Pest Infestation Laboratory. Thanks are due to Dr. Lucas for making an independent test of the method and for allowing us to use his data.