Air-tight storage of grain; its effects on insect pests. I. Calandra granaria L.(Coleoptera, Curculionidae).

Abstract

The responses of adult and immature Calandra granaria L. to high concentrations of carbon dioxide and low concentrations of oxygen have been determined. To bring about 100 per cent. mortality of all stages requires an increase of carbon dioxide to 40 per cent. or a decrease of oxygen to 2 per cent. The respiratory quotient of the species has been measured and it is shown that the death of the insects, under air-tight grain storage conditions, is due to the depletion of oxygen caused by the respiration of the insects and the grain and not to the accumulation of carbon dioxide. The adult insects are the most resistant stage and the first insects larvae the most susceptible. Estimates for the time required for the insects to die and for the amount of damage they cause before death are given.