Dielectric heating with radio waves (RW) and microwaves is an alternative treatment to hazardous chemicals or hot air for pest control. RW can be used to heat large bulky materials homogeneously and smoothly to eliminate embedded pest organisms. Dielectric heating enables selective overheating of certain materials in a heterogeneous mixture. This feature of electromagnetic heating methods, in contrast to techniques based on thermal conduction, is caused by significant differences in the dielectric properties of pest organisms and matrix materials. This study proves unambiguously that selective heating of cylindrical pest organisms in wood matrices occurs under defined conditions. The selective heating effect strongly depends on the orientation of the pest organisms in the electric field.