THE EFFECT OF THERMAL AND CHILLING SEQUENCY ON THE MORTALITY OF TRIBOLIUM CONFUSUM (DUVAL) AND

Abstract

The result of studying the effect of two insects species Tribolium confusum ( Duval) and Rhizopertha dominica (F.) on responding to successive exposure periods of high and low temperature showed that the high temperature 45 , 50 and 55 0 C successive with -5 0 C reveled a significant effect on mean mortality percentage which reached 66.94 , 93.33 and 64.17 % respectively for T. confusum and 88.06 , 73.33 and 81.94 % respectively for R. dominica . The results also appear that the mean mortality percentage of the two insect species were increased as the exposer periods to successive temperatures increased and reached 5.93 , 16.67 , 34,34 and 35,56 % respectively for T. confusum at 45 0 C and 27.04 , 38.15 , 44.44 and 66.67 % respectively at 50 0 C and 11.11 , 47.41 , 74.82 and 100 % respectively at 55 0 C , while for R. dominica reached 28.15 , 39.26 ,43.33 and 45.15 % respectively at 45 0 C and 12.96 , 39.26 , 54.82 and 55.56 % respectively at 50 0 C and 22.96 , 44.44 , 55.56 and 100 % respectively at 55 0 C .