An extermination apparatus for extermination of insect pests is disclosed herein, In various aspects, the apparatus includes a housing that defines a chamber within. The chamber has a mouth that may be interposed over a surface to be treated, in various aspects. The housing, in various aspects, is, adapted to admit steam from a steam supply into the chamber. A bonnet may be removably disposed over the mouth of the chamber, with the bonnet being permeable to steam to allow the steam to flow from the chamber through the mouth and through the bonnet disposed over the mouth. Related methods of use of the extermination apparatus are also disclosed herein. This Abstract is presented to meet requirements of 37 C.F.R. §1.72(b) only. This Abstract is not intended to identify key elements of the apparatus and methods disclosed herein or to delineate the scope thereof.