Hidden insect infestations can be detected by means of a system that provides a readily identifiable signal from insect-produced carbon dioxide (CO₂), even in the presence of normal atmospheric CO₂. Our system is unique in that it uses an intermittent flow of a carrier gas with alternating intervals for sample collection and sample readout in conjunction with a bolus-activated infrared CO₂ analyzer. Testing is nondestructive, produces no byproducts, and has no effect on the insects. The method is applicable to a wide variety of materials, either packaged or bulk. Examples of detection capability are discussed. -- CCI