Use of reactive chemical methods to control insect degradation of cultural property poses significant risk of collateral damage to the object. Safer methods using inert gases such as argon have been implemented at the Metropolitan Museum of Art. A significant gap in knowlegde exists between the applicability of treatment times as derived from studies on insects in vitro to actual treatment time lengths for insects in vivo. Insects in vivo or in objects are acclimated to their envirlnment and may be in a number of different physiologically susceptible states (more than may be represented in vitro studies). A technique utilizing Fourier transform infrared spectroscopy has been used to measure insect gas by-products. The method shows promise for non-destructively assessing insect activity before and after treatment and for establishing necessary length of treatment times for objects. -- CAL