The sampling efficiency for Lycopodium and other spores of similar size is of the order of 99%. The sampled air is accelerated in a precision Jet and forced against the orifice of a tapered tube containing still air. This configuration is mounted above a hermetically sealed chamber in which the trapped particles fall under gravity and are evenly distributed on the base. The base of the chamber can hold an appropriate medium or detached leaf pieces of susceptible host plants.

After incubation, the colonies of the pathogen can be evaluated quantitatively. In this way, the aerial concentration of spores from cereal mildew, leaf rust and net blotch can be estimated, as well as the proportions coming from different varieties, and the frequency of particular races of each pathogen.