The aim of this study was to investigatethe efficacy of some plant dusts i.e. black pepper seeds dust (Piper nigrum L.); Cloves flowering buds (Syzegium aromaticum); Chili fruits dust (Capsicum frutescens); Cinnamon dust (Cinnamonum zeylanicum); Diatomaceous earth (DE) dust in comparison with katel-sous dust against Rhizopertha dominica (F.) at 30+1oC and 65+5% RH, also the efficacy of two organophosphorus insecticides namely malathion and piromiphos –methyl (Actellic) and one botanical insecticide (Neemazal T/S 1% Azadirachtin) was evaluated. The results indicated that adult mortality was concentration and exposure period dependent. Adult mortality was increased with increasing the dust concentration and exposure period. The results of the various dusts against Rhizopertha dominica adults indicated that DE was the most effective followed by black pepper dust, cloves flowering dust, katel-sous dust and chili dust which was the least effective one. On the other hand the highest tested cinnamon dust concentration (6% w/w) resulted a lower mortality (less than 40%) even after two weeks from treatment. Results of the toxicity index of the various tested insecticides against Rhizopertha dominica (F.), revealed that Actellic was the most effective followed by Malathion and Neemazal which was the least effective one.