A method and apparatus for capacitively sensing one or more pests is disclosed. The detector may be employed as either a passive detector and/or as a part of a combined detector and trap. The sensor system includes at least two sensor electrodes and a capacitance sensing circuit. When a non-capacitive object, such as a pest, approaches the sensor electrodes, the capacitance of the sensor electrodes increases due to the object having a higher dielectric constant than air. A capacitance sensing circuit detects the increased capacitance and provides an output signal that a pest has entered the area being monitored. The capacitance sensing circuit may also be constructed to measure the change in the electrode in order to determine the size and/or type of pest based on a characteristic change.