reported that during heat treatment of mills using gas heaters to 50-60o C, old instars and pupae appeared relatively heat tolerant compared to other life stages. Mahroof et al. (2003 b) conducted experiments to study time-mortality relationships for life stages of T. castaneum exposed to elevated temperature of 50-60oC. They concluded that young larvae were the most heat–tolerant stage. Hamid and Boulanger (1969) concluded that the mortality of larvae was the same as the adult T. confusum at different temperatures