Dill (Anethum graveolens Lino.) and Cumin (Cumminum cyminum Linn.) seed extracts in petroleum ether alone and undermodified atmospheres (MAs) of 24 & 48% co? and 99.8% N2 were tested at 28±1°C and 55±5% RH. against the active and diapausd larvae of Trogoderma granarium in the laboratory. The results showed that larval mortality was concentration and exposure period- dependent. Both larval mortality increased with raising the period of exposure and concentration. Active larvae were niore sensitive to both extracts than diapausing one. Dill seed extract was more effective than Cumin extract against active and diapausing larvae of T. granarium. The combined action of the treatments of Dill and Cumin seed extracts under modified atmospheres of various carbon dioxide concentrations or MA of very high nitrogen content resulted in either synergistic or additive effects with both larvae at the different periods of exposure.